From willamette-fcst at listsmart.osl.state.or.us Mon Aug 2 08:58:27 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Mon, 2 Aug 2010 08:58:27 -0700 Subject: [willamette-fcst] Silverton Hills Forecast - Mon, August 2 2010 Message-ID: <8CD18C5BD70D6F4BB2B636295905299C8A2FF588@WPODFEXCL01.ODF.STATE.OR.US> SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT MON AUG 2 2010 BURN ADVISORY: Agricultural burning burning is not recommended. Prep burning is allowed from 12:00pm to 2:00pm with a 50 acre limit. Propane flaming is allowed from 12:00pm to 5:00pm. WEATHER DISCUSSION: A weak upper-level trough remains over the Pacific Northwest this morning. Visible satellite imagery shows a band of what appears to be elevated wild fire smoke extending from eastern and central Washington back across northwestern Oregon, in association with an upper-level disturbance moving through the region. Marine low clouds were blanketing the coast, but inland penetration was limited to the extreme northern Willamette Valley, near Portland. There were also patches of light fog in the extreme south valley, near Eugene. Skies were mostly sunny over the remainder of the state. The Salem sounding showed several degrees of warming aloft, since Sunday morning. The marine air was very shallow with quite dry conditions above 2500 feet. The low-level temperature profile is stable, with a temperature inversion at about 4700 feet that should cap maximum mixing heights this afternoon. The weak upper-level disturbance that is over northwestern Oregon this morning is forecast to continue eastward into central Oregon this afternoon. Northwesterly flow aloft should promote an afternoon sea breeze. Transport winds and pressure gradients will need to be monitored for the possibility of limited open burning later this afternoon. TODAY'S FORECAST: Smoke and haze aloft this morning, otherwise mostly sunny. After reaching 80 degrees on Sunday, Salem's high temperature today will be near 84 degrees. The mixing height will climb to 3000 feet about noon and likely top out at around 4700 feet later this afternoon. A cooling sea breeze will drop the mixing height to 1500 feet by shortly before sunset. Surface and transport winds will be N 3-6 this morning and back to NW 6-10 this afternoon. Relative humidity will drop to 50% by 1 p.m. and to near 36% by late this afternoon. The ventilation index will climb to about 36 late this afternoon. Silverton area sunset tonight: 8:32 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 71 79 84 75 Relative Humidity: 57% 44% 36% 50% Surface Wind Direction: 350 320 310 280 Surface Wind Speed: 4 5 7 7 Transport Wind Direction: 360 310 330 290 Transport Wind Speed: 5 6 8 15 Estimated Mixing Height: 2400 3800 4700 1500 Ventilation Index: 12 23 38 22 EXTENDED DISCUSSION: Little change to the overall weather pattern is expected through Friday, with a weak upper-level trough remaining over the Pacific Northwest. Varying degrees of onshore flow will maintain at least a chance of open burning each afternoon. The onshore flow may weaken a bit on Wednesday, as the upper-level flow turns southwesterly, and then strengthen again late Thursday and Friday. The best chances for open burning opportunities appear to be Tuesday and Thursday afternoons, but that is certainly subject to change. EXTENDED FORECAST: Tuesday: Patchy morning clouds, then mostly sunny. Wind: NW 5-12 mph. 55/84 Wednesday: Mostly Sunny. Wind: NNW 5-12 mph. 55/86 Thursday: Mostly sunny. Wind: NW 5-15 mph. 56/84 Friday: Morning clouds, then mostly sunny. 55/79 Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Mon Aug 2 11:58:41 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Mon, 2 Aug 2010 11:58:41 -0700 Subject: [willamette-fcst] Silverton Hills Forecast - Mon, August 2 2010 Message-ID: <8CD18C5BD70D6F4BB2B636295905299C8A35F79B@WPODFEXCL01.ODF.STATE.OR.US> SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT MON AUG 2 2010 BURN ADVISORY: Agricultural burning burning is not recommended. Prep burning is allowed from now to 2:00pm with a 50 acre limit. Propane flaming is allowed from now to 5:00pm. WEATHER DISCUSSION: Visible satellite imagery shows marine low clouds still covering much of western Washington and extending along the Washington coast and most of the northern and central Oregon coast. Patches of low clouds made it inland into the extreme northern Willamette Valley this morning but were evaporating at midday. Satellite imagery also shows elevated wildfire smoke continuing to cover much of central and eastern Washington. Some of that smoke got rotated south and west, to over northwestern and north-central Oregon, by the upper-level trough over the region. Skies were mostly sunny over the remainder of the state, at midday. Temperatures in the Willamette Valley are generally running 5-8 degrees warmer than 24 hours ago. The morning sounding over Salem showed several degrees of warming aloft, since Sunday morning. The marine air is very shallow with quite dry conditions above 2500 feet. The low-level temperature profile is stable, with a temperature inversion at about 4700 feet that should cap maximum mixing heights this afternoon. A weak upper-level disturbance that was over northwestern Oregon this morning is forecast to continue eastward into central Oregon this afternoon. Daytime heating is already triggering some minor cumulus cloud development over the southern Cascades and over central Oregon, but the very dry air mass will limit afternoon thunderstorm development. Northwesterly flow aloft should promote an afternoon sea breeze into the Willamette Valley. Transport winds and pressure gradients will need to be monitored for the possibility of limited open burning later this afternoon. TODAY'S FORECAST: Smoke and haze aloft, otherwise mostly sunny. Salem's high temperature today will be near 84 degrees. The mixing height will climb to around 4700 feet later this afternoon. A cooling sea breeze will drop the mixing height to 1500 feet by shortly before sunset. Surface and transport winds become NW 6-10 this afternoon. Relative humidity will drop to 50% by 1 p.m. and to near 36% by late this afternoon. The ventilation index will climb to about 36 late this afternoon. Silverton area sunset tonight: 8:32 pm EXTENDED DISCUSSION: Little change to the overall weather pattern is expected through Friday, with a weak upper-level trough remaining over the Pacific Northwest. Varying degrees of onshore flow will maintain at least a chance of open burning each afternoon. The onshore flow may weaken a bit on Wednesday, as the upper-level flow turns southwesterly, and then strengthen late Thursday and Friday. The best chances for open burning opportunities later this week appear to be Tuesday and Thursday afternoons, but that may change. EXTENDED FORECAST: Tuesday: Patchy morning clouds, then mostly sunny. Wind: NW 5-12 mph. 55/84 Wednesday: Mostly Sunny. Wind: NNW 5-12 mph. 55/86 Thursday: Mostly sunny. Wind: NW 5-15 mph. 56/84 Friday: Morning clouds, then mostly sunny. 55/79 Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Tue Aug 3 08:58:20 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Tue, 3 Aug 2010 08:58:20 -0700 Subject: [willamette-fcst] Silverton Hills Forecast - Tue, August 3 2010 Message-ID: <8CD18C5BD70D6F4BB2B636295905299C8A35F91D@WPODFEXCL01.ODF.STATE.OR.US> SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT TUE AUG 3 2010 BURN ADVISORY: Agricultural burning burning is not recommended. Prep burning is not allowed. Propane flaming is allowed from 2:00pm to 5:00pm. WEATHER DISCUSSION: A broad upper-level trough remains over the Pacific Northwest this morning with smaller scale disturbances rotating through it. One system moved across western Oregon Monday morning and brought scattered thunderstorms to eastern Oregon Monday afternoon. In its wake, weak ridging quickly stabilized the atmosphere across western Oregon Monday evening. Onshore flow increased overnight with visible satellite imagery showing marine low clouds penetrating into most of the Willamette Valley this morning. The Salem sounding this morning was similar to Monday morning with a mixing cap at about 4800 feet. The low-level moisture is a bit deeper this morning, but the low clouds should give way to sunshine by midday. Another weak system is over Vancouver Island, British Columbia this morning and is forecast to drop southward into western Washington later this afternoon. It may produce a few showers across western Washington but not likely as far south as western Oregon. Increasing westerly flow aloft will act to increase the onshore flow this afternoon, which may create an open burning opportunity. TODAY'S FORECAST: Morning clouds, then sunny and warm. After reaching 85 degrees on Monday, Salem's high temperature today will be near 84 degrees. The mixing height will not climb to 3000 feet until about 2 p.m. and likely top out at around 4800 feet around 5 p.m. A cooling sea breeze will drop the mixing height to 1500 feet by shortly before sunset. Surface and transport winds will be NW 3-6 this morning and increase to NW 5-12 this afternoon. Relative humidity will drop to 50% by 1 p.m. and to near 36% by late this afternoon. The ventilation index will climb to about 38 late this afternoon. Silverton area sunset tonight: 8:30 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 69 78 84 76 Relative Humidity: 59% 43% 36% 45% Surface Wind Direction: 330 310 300 300 Surface Wind Speed: 3 5 6 7 Transport Wind Direction: 300 310 300 300 Transport Wind Speed: 3 5 8 12 Estimated Mixing Height: 2200 3000 4800 1500 Ventilation Index: 7 15 38 18 EXTENDED DISCUSSION: Little change to the overall weather pattern is expected through Friday, with a weak upper-level trough remaining over the Pacific Northwest. Varying degrees of onshore flow will maintain at least a chance of open burning each afternoon. The onshore flow may weaken a bit on Wednesday, and then strengthen again late Thursday and Friday, which could lead to marginal open burning opportunities. EXTENDED FORECAST: Wednesday: Morning clouds, then mostly sunny. Wind: NNW 5-12 mph. 55/84 Thursday: Morning clouds, then mostly sunny. Wind: NW 5-15 mph. 56/83 Friday: Morning clouds, then sunny. 55/82 Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Tue Aug 3 11:58:58 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Tue, 3 Aug 2010 11:58:58 -0700 Subject: [willamette-fcst] Silverton Hills Forecast - Tue, August 3 2010 Message-ID: <8CD18C5BD70D6F4BB2B636295905299C8A35F9E4@WPODFEXCL01.ODF.STATE.OR.US> SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT TUE AUG 3 2010 BURN ADVISORY: Agricultural burning burning is not recommended. Prep burning is not allowed. Propane flaming is allowed from 2:00pm to 5:00pm. WEATHER DISCUSSION: A broad upper-level trough remains over the Pacific Northwest with smaller scale disturbances rotating through it. visible satellite imagery showed marine low clouds giving way to sunshine across the Willamette Valley at midday with temperature running about 5 degrees cooler than 24 hours ago. There is mild gradient-stacking at midday, which should be overcome by daytime heating. Another upper-level disturbance will drop into western Washington later this afternoon. It may produce a few showers across western Washington but not likely as far south as western Oregon. Increasing west-southwesterly flow aloft will increase the onshore flow this afternoon. Transport winds will need to be monitored for the possibility of open burning this afternoon. TODAY'S FORECAST: Becoming mostly sunny and warm. Salem's high temperature today will be near 84 degrees. The mixing height will not climb to 3000 feet until about 2 p.m. and likely top out at around 4800 feet around 5 p.m. A cooling sea breeze will drop the mixing height to 1500 feet by shortly before sunset. Surface and transport winds will be NW 3-6 this morning and increase to NW 5-12 this afternoon. Relative humidity will drop to 50% by 1 p.m. and to near 36% by late this afternoon. The ventilation index will climb to about 38 late this afternoon. Silverton area sunset tonight: 8:30 pm EXTENDED DISCUSSION: Little change to the overall weather pattern is expected through Friday, with a weak upper-level trough remaining over the Pacific Northwest. Varying degrees of onshore flow will maintain at least a chance of open burning each afternoon. The onshore flow may weaken a bit on Wednesday, and then strengthen again late Thursday and Friday, which could lead to marginal open burning opportunities. EXTENDED FORECAST: Wednesday: Morning clouds, then mostly sunny. Wind: NNW 5-12 mph. 55/84 Thursday: Morning clouds, then mostly sunny. Wind: NW 5-15 mph. 56/83 Friday: Morning clouds, then sunny. 55/82 Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Wed Aug 4 08:57:04 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Wed, 4 Aug 2010 08:57:04 -0700 Subject: [willamette-fcst] Silverton Hills Forecast - Wed, August 4 2010 Message-ID: <8CD18C5BD70D6F4BB2B636295905299C8A35FB44@WPODFEXCL01.ODF.STATE.OR.US> SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT WED AUG 4 2010 BURN ADVISORY: Recommended burn times for agricultural burning are from noon to 6:30pm. Prep burning is not allowed. Propane flaming is allowed from 2:00pm to 5:00pm. WEATHER DISCUSSION: A broad upper-level trough remains over the Pacific Northwest. An upper-level disturbance is triggering thundershowers over the northern Washington Cascades this morning with a more stable west-southwesterly flow aloft over Oregon. Little change in the upper-level weather pattern is forecast today with shower and thundershower activity possibly sagging southward to near the Washington/Oregon border this afternoon. Onshore flow brought a fresh surge of cool marine air inland last night. Visible satellite imagery showed marine low clouds extending from the coast to the crest of the Cascades this morning and extending southward across the entire Willamette Valley and into Douglas County. The Salem sounding this morning showed a stable atmosphere with the moist marine layer extending from the surface up to about 3500 feet. Morning low clouds should give way to mostly sunny skies by early afternoon. The onshore flow is forecast to be slightly weaker today, so even though the morning clouds will burn off later, afternoon temperatures should recover to about where they were on Tuesday. Once again, transport winds may turn just enough onshore to allow for limited open burning later this afternoon. TODAY'S FORECAST: Morning clouds, then sunny and warm. After reaching 82 degrees on Tuesday, Salem's high temperature today will be near 82 degrees again today. The mixing height will not climb to 3000 feet until about 2 p.m. and will likely top out at around 3800 feet around 5 p.m. A cooling sea breeze will drop the mixing height to 2000 feet by shortly before sunset. Surface and transport winds will be light NW to N this morning, then increase to NNW 5-10 this afternoon and become WNW near 10 mph this evening. Relative humidity will drop to 50% by 2 p.m. and to near 40% by late this afternoon. The ventilation index will climb to about 30 late this afternoon. Silverton area sunset tonight: 8:29 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 67 76 82 76 Relative Humidity: 63% 48% 40% 48% Surface Wind Direction: 360 340 330 280 Surface Wind Speed: 4 5 7 7 Transport Wind Direction: 340 350 340 300 Transport Wind Speed: 4 6 8 10 Estimated Mixing Height: 2000 2800 3800 2000 Ventilation Index: 8 17 30 20 EXTENDED DISCUSSION: Little change to the overall weather pattern is expected through Friday, with a weak upper-level trough remaining over the Pacific Northwest. Weak onshore flow will maintain the pattern of morning clouds with afternoon sunshine. Ventilation conditions may allow for limited afternoon open burning each day. Even cooler temperatures are forecast for this weekend, with a weak cold front likely making it onshore late Saturday and early Sunday. Moisture with this system is very limited, but it may bring some drizzle to the coast and possibly the Willamette Valley Sunday morning. EXTENDED FORECAST: Thursday: Morning clouds, then partly cloudy. Wind: NW 5-15 mph. 55/83 Friday: Morning clouds, then partly cloudy. Wind: NW 5-15 mph. 55/82 Saturday: Morning clouds, then partly cloudy. 55/77 Sunday: Chance of morning drizzle. Partly sunny in the afternoon. 54/75 Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Wed Aug 4 11:57:30 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Wed, 4 Aug 2010 11:57:30 -0700 Subject: [willamette-fcst] Silverton Hills Forecast - Wed, August 4 2010 Message-ID: <8CD18C5BD70D6F4BB2B636295905299C8A35FC15@WPODFEXCL01.ODF.STATE.OR.US> SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT WED AUG 4 2010 BURN ADVISORY: Recommended burn times for agricultural burning are from now to 6:30pm. Prep burning is not allowed. Propane flaming is allowed from 2:00pm to 5:00pm. WEATHER DISCUSSION: An upper-level disturbance triggered thundershowers over the northern Washington Cascades early this morning, while a more stable west-southwesterly flow aloft kept conditions dry over Oregon, except for a few patches of drizzle. Little change in the upper-level weather pattern is forecast today with a few afternoon showers and thundershowers likely developing over the Washington Cascades and possibly as far south as extreme northern Oregon. Marine low clouds continued to blanket much of the Willamette Valley at midday but were breaking up over the coast range. Skies were generally sunny over the remainder of the state. Over in central Oregon, smoke from a wildfire, just south of Sisters Oregon, was covering much of northern Deschutes County and streaming northward over southern Jefferson County. It is unlikely that any smoke from that fire will push west of the Cascades today. Skies should soon begin clearing over the Willamette Valley with considerable sunshine likely after about 2 p.m. The late-morning ODA surface analysis showed only minor gradient-stacking of the onshore flow across western Oregon, which could be overcome by afternoon heating. However, a thermal trough over extreme southwestern Oregon was helping to create a strong northerly gradient, known as the "Medford Draw," across western Oregon. That will likely keep surface and transport winds too northerly for open burning this afternoon. However, direct monitoring of the transport winds, via pibals, will begin at 1 p.m. TODAY'S FORECAST: Mostly cloudy early this afternoon with clearing skies in the mid-to-late afternoon. Salem's high temperature today will be near 80 degrees. The mixing height will not climb to 3000 feet until about 2 p.m. and will likely peak near 3800 feet around 5 p.m. A cooling sea breeze will drop the mixing height to 2000 feet by shortly before sunset. Surface and transport winds will be light NW to NE through early this afternoon, then become mostly northerly and increase to 5-12 mph in the mid-to-late afternoon. Surface and transport winds will become NW 5-12 mph this evening. Relative humidity will drop to 50% by 3 p.m. and to near 42% by late this afternoon. The ventilation index will climb to about 30 late this afternoon. Silverton area sunset tonight: 8:29 pm EXTENDED DISCUSSION: Little change to the overall weather pattern is expected through Friday, with a weak upper-level trough remaining over the Pacific Northwest. The onshore flow is forecast to increase, which may give afternoon transport winds more of a westerly component both Thursday and Friday. That increases the chances for open burning opportunities. Slightly cooler temperatures are forecast for this weekend, as the upper-level trough strengthens and swings a weak cold front onshore. Moisture with this system is very limited, but it may bring some drizzle to the coast and possibly the Willamette Valley Sunday morning. A dry and mild northwesterly flow aloft is forecast for early next week with continued onshore flow possibly providing enough ventilation for open burning. EXTENDED FORECAST: Thursday: Morning clouds, then partly cloudy. Wind: NW 5-15 mph. 55/83 Friday: Morning clouds, then partly cloudy. Wind: NW 5-15 mph. 55/82 Saturday: Morning clouds, then partly cloudy. 55/77 Sunday: Chance of morning drizzle. Partly sunny in the afternoon. 54/75 Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Thu Aug 5 08:58:36 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Thu, 5 Aug 2010 08:58:36 -0700 Subject: [willamette-fcst] Silverton Hills Forecast - Thu, August 5 2010 Message-ID: <8CD18C5BD70D6F4BB2B636295905299C8A35FDFA@WPODFEXCL01.ODF.STATE.OR.US> SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT THU AUG 5 2010 BURN ADVISORY: Recommended burn times for agricultural burning are from 1:00pm to 6:30pm. Prep burning is allowed from 1:00pm to 2:00pm with a 50 acre limit. Propane flaming is allowed from 1:00pm to 5:00pm. WEATHER DISCUSSION: An upper-level trough remains over the Pacific Northwest. The main circulation center is over western Washington, with a few showers falling over the northern Washington Cascades this morning. A weaker mid-level circulation center is over southwestern Oregon, and that is having a significant impact on air quality across western Oregon. The Salem sounding this morning showed easterly winds from 5000 feet up to about 8000 feet, which circulated some wildfire smoke, from the Rooster Rock Fire in central Oregon, over the Cascades and across the Willamette Valley during the night. Nephelometer readings in the northern Cascades and in the Willamette Valley are slightly elevated this morning, and skies appear hazy. Onshore flow is weak this morning. Visible satellite imagery shows low clouds along the coast with only minor penetration into the western valleys. Increased sunshine will result in valley temperatures climbing into the mid 80s this afternoon. Air quality should begin improving this afternoon, as both upper-level disturbances slowly drift eastward. Winds will shift to northwesterly, below about 5000 feet, as onshore flow increases across westerly Oregon. However, the winds above 5000 feet may continue to circulate some elevated wildfire smoke over the region through this evening, before turning onshore tonight and Friday. Transport winds will need to be monitored for the possibility of open burning this afternoon. TODAY'S FORECAST: Mostly sunny, hazy, and warmer. After reaching 81 degrees on Wednesday, Salem's high temperature today will be near 86 degrees. The mixing height will climb to 3000 feet about 1 p.m. and will likely top out near 4500 feet around 5 p.m. A stronger evening sea breeze is expected today with the mixing height dropping to near 2000 feet by sunset. Surface and transport winds will be NW 3-6 mph this morning, then increase to NW 5-10 this afternoon and NW 7-12 this evening. Relative humidity is forecast to drop to 50% by 2 p.m. and to near 36% by 5 p.m. The ventilation index will climb to about 45 late this afternoon. Silverton area sunset tonight: 8:28 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 74 82 86 77 Relative Humidity: 57% 43% 36% 47% Surface Wind Direction: 340 310 310 270 Surface Wind Speed: 3 5 7 7 Transport Wind Direction: 320 330 320 310 Transport Wind Speed: 4 6 10 12 Estimated Mixing Height: 2000 3700 4500 2000 Ventilation Index: 8 22 45 24 EXTENDED DISCUSSION: The upper-level troughs are both forecast to finally shift east of the Cascades Friday with the winds at transport level and aloft turning onshore. That should clear the skies of wildfire smoke and may provide an open burning opportunity Friday afternoon. Morning clouds will likely penetrate inland to the Cascade crest with high temperatures cooling back into the low 80s across the Willamette valley. Stronger onshore flow will bring further cooling over the weekend, with a weak cold front forecast to come onshore Saturday evening. Marine clouds will be extensive by Sunday morning with local drizzle possible. High temperatures should fall to about 10 degrees below normal by Sunday. Another upper-level trough is forecast to drop into the region early next week for continued cooler than normal conditions and strong onshore flow. Open burning opportunities may be possible, if the deep marine layer does not create too much gradient-stacking. EXTENDED FORECAST: Friday: Morning clouds, then partly cloudy. Wind: NW 5-15 mph. 55/82 Saturday: Morning clouds, then partly cloudy. 55/77 Sunday: Chance of morning drizzle. Partly sunny in the afternoon. 54/75 Monday: Morning clouds. Afternoon clearing. 54/78 Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Thu Aug 5 11:58:47 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Thu, 5 Aug 2010 11:58:47 -0700 Subject: [willamette-fcst] Silverton Hills Forecast Thu August 5, 2010 Message-ID: <8CD18C5BD70D6F4BB2B636295905299C8A35FEAA@WPODFEXCL01.ODF.STATE.OR.US> SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT THU AUG 5 2010 BURN ADVISORY: Recommended burn times for agricultural burning are from 1:00pm to 6:30pm. Prep burning is allowed from 1:00pm to 3:00pm with a 50 acre limit. Propane flaming is allowed from 1:00pm to 5:00pm. WEATHER DISCUSSION: An upper-level trough remains over the Pacific Northwest. The main circulation center is over western Washington. A weaker mid-level circulation center is over southwestern Oregon. The Salem sounding this morning showed easterly winds from 5000 feet up to about 8000 feet, which circulated some wildfire smoke, from the Rooster Rock Fire in central Oregon, over the Cascades and across the Willamette Valley during the night. Nephelometer readings in the northern Cascades and in the Willamette Valley remain slightly elevated late this morning, and skies are still a bit hazy. The surface flow is onshore with 2.7 mb from Newport to Salem and 1.4 mb from Salem to Redmond. Visible satellite imagery shows low clouds have retreated to just along the coast with sunny skies over the interior of the state. Temperatures in the Willamette Valley are running as much as 10 degrees warmer than 24 hours ago. Increased sunshine will result in valley temperatures climbing into the mid 80s this afternoon. Air quality should begin improving this afternoon, as both upper-level disturbances slowly drift eastward. Winds will shift to northwesterly, below about 5000 feet, as onshore flow increases across westerly Oregon. However, the winds above 5000 feet may continue to circulate some elevated wildfire smoke over the region through this evening, before turning onshore tonight and Friday. Transport winds will need to be monitored for the possibility of open burning this afternoon. TODAY'S FORECAST: Mostly sunny, hazy, and warmer. Salem's high temperature today will be near 86 degrees. The mixing height will climb to 3000 feet about 1 p.m. and will likely top out near 4500 feet around 5 p.m. A stronger evening sea breeze is expected today with the mixing height dropping to near 2000 feet by sunset. Surface and transport winds will increase to NW 5-10 this afternoon and NW 7-12 this evening. Relative humidity is forecast to drop to 50% by 2 p.m. and to near 36% by 5 p.m. The ventilation index will climb to about 45 late this afternoon. Silverton area sunset tonight: 8:28 pm EXTENDED DISCUSSION: The upper-level troughs are both forecast to finally shift east of the Cascades Friday with the winds at transport level and aloft turning onshore. That should clear the skies of wildfire smoke and may provide an open burning opportunity Friday afternoon. Morning clouds will likely penetrate inland to the Cascade crest with high temperatures cooling back into the low 80s across the Willamette valley. Stronger onshore flow will bring further cooling over the weekend, with a weak cold front forecast to come onshore Saturday evening. Marine clouds will be extensive by Sunday morning with local drizzle possible. High temperatures should fall to about 10 degrees below normal by Sunday. Another upper-level trough is forecast to drop into the region early next week for continued cooler than normal conditions and strong onshore flow. Open burning opportunities may be possible, if the deep marine layer does not create too much gradient-stacking. EXTENDED FORECAST: Friday: Morning clouds, then partly cloudy. Wind: NW 5-15 mph. 55/82 Saturday: Morning clouds, then partly cloudy. 55/77 Sunday: Chance of morning drizzle. Partly sunny in the afternoon. 54/75 Monday: Morning clouds. Afternoon clearing. 54/78 Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Fri Aug 6 08:54:33 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Fri, 6 Aug 2010 08:54:33 -0700 Subject: [willamette-fcst] Silverton Hills Forecast - Fri, August 6 2010 Message-ID: <8CD18C5BD70D6F4BB2B636295905299C8A35FFB7@WPODFEXCL01.ODF.STATE.OR.US> SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT FRI AUG 6 2010 BURN ADVISORY: Recommended burn times for agricultural burning are from 1:00pm to 6:30pm. Prep burning is allowed from 1:00pm to 3:00pm with a 50 acre limit. Propane flaming is allowed from 1:00pm to 5:00pm. WEATHER DISCUSSION: An upper-level trough stretches from western Washington, across western Oregon, to northern California this morning. Wildfire smoke from both the Rooster Rock Fire, in central Oregon, and from fires in southern British Columbia is still making skies hazy over western Oregon. Nephelometer readings remain slightly elevated this morning in the northern Cascades and in the Willamette Valley. Some improvement in air quality is likely today, as the upper-level trough slowly migrates eastward and the winds aloft turn onshore. The Salem sounding this morning still showed easterly winds between 2000 and 3000 feet, but all other levels had turned onshore. However, the onshore flow is still fairly weak this morning with just 1.6 mb from Newport to salem and 1.6 mb from Salem to Redmond. Visible satellite imagery shows low clouds along the coast with some inland penetration up the Columbia River into the extreme northern Willamette Valley. The remainder of the valley had hazy sunshine. Temperatures were generally running only a degree or two cooler than 24 hours ago. The flow aloft is forecast to turn onshore, at all levels, by this afternoon with very slight cooling aloft likely taking a few degrees off of valley high temperatures. Since the smoke plumes from area wildfire extend close to 100 miles offshore, expect the increasing westerly flow aloft to only slowly clear the hazy conditions across western Oregon. Transport winds will need monitoring this afternoon for the possibility of ventilation conditions improving enough for limited open burning. TODAY'S FORECAST: Mostly sunny and hazy. A touch cooler. After reaching 88 degrees on Thursday, Salem's high temperature today will be near 84 degrees. The mixing height will climb to 3000 feet about 2 p.m. and likely top out near 4000 feet around 5 p.m. An evening sea breeze should drop the mixing height to near 2000 feet by 8 p.m. Surface and transport winds will be NW 3-6 mph this morning, then increase to NW 5-10 this afternoon and NW 7-12 this evening. Relative humidity is forecast to drop to 50% by 1 p.m. and to near 34% by 5 p.m. The ventilation index will climb to about 32 late this afternoon. Silverton area sunset tonight: 8:26 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 71 80 84 75 Relative Humidity: 55% 41% 34% 48% Surface Wind Direction: 320 310 320 290 Surface Wind Speed: 5 6 8 9 Transport Wind Direction: 310 320 320 310 Transport Wind Speed: 4 6 8 10 Estimated Mixing Height: 2200 3000 4000 2000 Ventilation Index: 9 18 32 20 EXTENDED DISCUSSION: Stronger onshore flow will bring further cooling over the weekend, with a weak cold front forecast to come onshore Saturday evening. Marine clouds will be extensive by Sunday morning with local drizzle possible. High temperatures should fall to about 10 degrees below normal by Sunday. Another upper-level trough is forecast to drop into the region Monday for continued cooler than normal conditions and moderate to strong onshore flow. That may create an open burning opportunity and will need to be monitored closely. The trough is forecast to weaken on Tuesday with decreasing onshore flow leading warmer temperatures and decreasing the chances for open burning opportunities. Long-range computer models are inconsistent. Some are showing a cool northwesterly flow aloft for later next week, while others have temperatures warming to above normal. EXTENDED FORECAST: Saturday: Morning clouds, then partly cloudy. 55/79 Sunday: Chance of morning drizzle. Partly sunny in the afternoon. 54/75 Monday: Morning clouds, then mostly sunny. 54/79 Tuesday: Morning clouds, then mostly sunny. 53/84 Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Fri Aug 6 09:23:57 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Fri, 6 Aug 2010 09:23:57 -0700 Subject: [willamette-fcst] Corrected Silverton Hills Forecast Fri August 6 2010 Message-ID: <8CD18C5BD70D6F4BB2B636295905299C8A35FFC8@WPODFEXCL01.ODF.STATE.OR.US> SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT FRI AUG 6 2010 ...Corrected for prep burning (not allowed)... BURN ADVISORY: Recommended burn times for agricultural burning are from 1:00pm to 6:30pm. Prep burning is not allowed. Propane flaming is allowed from 1:00pm to 5:00pm. WEATHER DISCUSSION: An upper-level trough stretches from western Washington, across western Oregon, to northern California this morning. Wildfire smoke from both the Rooster Rock Fire, in central Oregon, and from fires in southern British Columbia is still making skies hazy over western Oregon. Nephelometer readings remain slightly elevated this morning in the northern Cascades and in the Willamette Valley. Some improvement in air quality is likely today, as the upper-level trough slowly migrates eastward and the winds aloft turn onshore. The Salem sounding this morning still showed easterly winds between 2000 and 3000 feet, but all other levels had turned onshore. However, the onshore flow is still fairly weak this morning with just 1.6 mb from Newport to salem and 1.6 mb from Salem to Redmond. Visible satellite imagery shows low clouds along the coast with some inland penetration up the Columbia River into the extreme northern Willamette Valley. The remainder of the valley had hazy sunshine. Temperatures were generally running only a degree or two cooler than 24 hours ago. The flow aloft is forecast to turn onshore, at all levels, by this afternoon with very slight cooling aloft likely taking a few degrees off of valley high temperatures. Since the smoke plumes from area wildfire extend close to 100 miles offshore, expect the increasing westerly flow aloft to only slowly clear the hazy conditions across western Oregon. Transport winds will need monitoring this afternoon for the possibility of ventilation conditions improving enough for limited open burning. TODAY'S FORECAST: Mostly sunny and hazy. A touch cooler. After reaching 88 degrees on Thursday, Salem's high temperature today will be near 84 degrees. The mixing height will climb to 3000 feet about 2 p.m. and likely top out near 4000 feet around 5 p.m. An evening sea breeze should drop the mixing height to near 2000 feet by 8 p.m. Surface and transport winds will be NW 3-6 mph this morning, then increase to NW 5-10 this afternoon and NW 7-12 this evening. Relative humidity is forecast to drop to 50% by 1 p.m. and to near 34% by 5 p.m. The ventilation index will climb to about 32 late this afternoon. Silverton area sunset tonight: 8:26 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 71 80 84 75 Relative Humidity: 55% 41% 34% 48% Surface Wind Direction: 320 310 320 290 Surface Wind Speed: 5 6 8 9 Transport Wind Direction: 310 320 320 310 Transport Wind Speed: 4 6 8 10 Estimated Mixing Height: 2200 3000 4000 2000 Ventilation Index: 9 18 32 20 EXTENDED DISCUSSION: Stronger onshore flow will bring further cooling over the weekend, with a weak cold front forecast to come onshore Saturday evening. Marine clouds will be extensive by Sunday morning with local drizzle possible. High temperatures should fall to about 10 degrees below normal by Sunday. Another upper-level trough is forecast to drop into the region Monday for continued cooler than normal conditions and moderate to strong onshore flow. That may create an open burning opportunity and will need to be monitored closely. The trough is forecast to weaken on Tuesday with decreasing onshore flow leading warmer temperatures and decreasing the chances for open burning opportunities. Long-range computer models are inconsistent. Some are showing a cool northwesterly flow aloft for later next week, while others have temperatures warming to above normal. EXTENDED FORECAST: Saturday: Morning clouds, then partly cloudy. 55/79 Sunday: Chance of morning drizzle. Partly sunny in the afternoon. 54/75 Monday: Morning clouds, then mostly sunny. 54/79 Tuesday: Morning clouds, then mostly sunny. 53/84 Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Fri Aug 6 11:58:47 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Fri, 6 Aug 2010 11:58:47 -0700 Subject: [willamette-fcst] Silverton Hills Forecast Fri August 6 2010 Message-ID: <8CD18C5BD70D6F4BB2B636295905299C8A36001D@WPODFEXCL01.ODF.STATE.OR.US> SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT FRI AUG 6 2010 BURN ADVISORY: Recommended burn times for agricultural burning are from 1:00pm to 6:30pm. Prep burning is not allowed. Propane flaming is allowed from 1:00pm to 5:00pm. WEATHER DISCUSSION: An upper-level trough stretches from western Washington, across western Oregon, to northern California at midday. Wildfire smoke from both the Rooster Rock Fire, in central Oregon, and from fires in southern British Columbia is still making skies hazy over western Oregon. Nephelometer readings remain slightly elevated this morning in the northern Cascades and in the Willamette Valley. Some improvement in air quality is likely today, as the upper-level trough slowly migrates eastward and the winds aloft turn onshore. Onshore flow is slowly increasing with just 2.2 mb from Newport to Salem and 2.4 mb from Salem to Redmond. Visible satellite imagery shows low clouds mostly just along the coast with sunny skies over the interior of Oregon. Valley temperatures are running a few degrees cooler than 24 hours ago. The flow aloft is also forecast to turn onshore by this afternoon. Since the smoke plumes from area wildfire extend offshore, expect the increasing westerly flow aloft to only slowly clear the hazy conditions across western Oregon. Transport winds will need monitoring this afternoon for the possibility of limited open burning. TODAY'S FORECAST: Mostly sunny and hazy. A touch cooler. Salem's high temperature today will be near 84 degrees. The mixing height will climb to 3000 feet about 2 p.m. and likely top out near 4000 feet around 5 p.m. An evening sea breeze should drop the mixing height to near 2000 feet by 8 p.m. Surface and transport winds will increase to NW 5-10 this afternoon and NW 7-12 this evening. Relative humidity is forecast to drop to 50% by 1 p.m. and to near 34% by 5 p.m. The ventilation index will climb to about 32 late this afternoon. Silverton area sunset tonight: 8:26 pm EXTENDED DISCUSSION: Stronger onshore flow will bring further cooling over the weekend, with a weak cold front forecast to come onshore Saturday evening. Marine clouds will be extensive by Sunday morning with local drizzle possible. High temperatures should fall to about 10 degrees below normal by Sunday. Another upper-level trough is forecast to drop into the region Monday for continued cooler than normal conditions and moderate to strong onshore flow. That may create an open burning opportunity and will need to be monitored closely. The trough is forecast to weaken on Tuesday with decreasing onshore flow leading warmer temperatures and decreasing the chances for open burning opportunities. Long-range computer models are inconsistent. Some are showing a cool northwesterly flow aloft for later next week, while others have temperatures warming to above normal. EXTENDED FORECAST: Saturday: Morning clouds, then partly cloudy. 55/79 Sunday: Chance of morning drizzle. Partly sunny in the afternoon. 54/75 Monday: Morning clouds, then mostly sunny. 54/79 Tuesday: Morning clouds, then mostly sunny. 53/84 Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Sun Aug 8 09:47:24 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Sun, 08 Aug 2010 11:47:24 -0500 Subject: [willamette-fcst] Silverton Hills Forecast - Sun, Aug 08 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT SUN AUG 08 2010 Test of mail system... Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. From willamette-fcst at listsmart.osl.state.or.us Sun Aug 8 09:47:32 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Sun, 08 Aug 2010 11:47:32 -0500 Subject: [willamette-fcst] Silverton Hills Forecast - Sun, Aug 08 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT SUN AUG 08 2010 Test of mail system... Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. From willamette-fcst at listsmart.osl.state.or.us Mon Aug 9 08:38:20 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Mon, 09 Aug 2010 10:38:20 -0500 Subject: [willamette-fcst] Silverton Hills Forecast - Mon, Aug 09 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT MON AUG 09 2010 BURN ADVISORY: Agricultural burning burning is not recommended. Prep burning is allowed from 12:00pm to 2:00pm with a 50 acre limit. Propane flaming is allowed from 12:00pm to 5:00pm. WEATHER DISCUSSION: A persistant broad upper trough remains over the Pacific Northwest this morning. Computer models indicate a disturbance now over British Columbia will drop southward during the day today to deepen the trough. Cooler air aloft witht his disturbance will allow mixing heights to approach 5000 feet by this afternoon. The morning ODF surface analysis shows high pressure offshore and low pressure centered in eastern Washington with a trough extending into north-central Oregon. The California thermal trough appears quite week this morning. Pressure gradients as of 8:00am incluced: Newport to Salem, 1.1 mb onshore and Salem to Redmond, 3.5 mb onshore. Thus there is gradient stacking to the east. However, any clearing in the Willamette Valley will warm temperatures and lower pressures evening out the pressure gradients. We will monitor pressure gradients through the day. Computer model forecasts indicate a northwesterly transport wind this afternoon, likely coming around enough to allow smoke evacuation to the east of the valley. The wind pattern is such that the Santiam River Canyon will be vulnerable to smoke, however. Models also indicate that winds will become more northerly during the early evening hours suggesting that the window of opportunity will close by about 5:00pm. Expect clouds this morning, partial clearing this afternoon. Salem's high temperature today will be near 79. Relative humidity drops to 50% by 11am. Minimum relative humidity 35%. Sunset tonight: 8:22 pm. THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 66 76 79 71 Relative Humidity: 58% 39% 35% 46% Surface Wind Direction: 360 320 310 290 Surface Wind Speed: 6 7 9 8 Transport Wind Direction: 350 320 310 300 Transport Wind Speed: 3 5 7 10 Estimated Mixing Height: 2900 4100 4900 1000 Ventilation Index: 9 20 34 10 EXTENDED DISCUSSION: The upper level disturbance dropping southward from BC today will carve out an upper level low over the Pacific Northwest by tonight. This low could produce some showers on Tuesday, wetting fields and eleminating any burn opportunity. Wednesday, however, the low should drift east and there is potential for some burning during the afternoon. As the low continues to drift eastward a strong upper high noses in from the Pacific Ocean and into southern BC giving northeasterly flow aloft and much warmer temperatures for the end of the week and the weekend. EXTENDED FORECAST: Tuesday: Partly sunny but a chance for showers. High 73. Wind NNW 5-8. Wednesday: Partly sunny, high 79. Afternoon winds NW 4-7. Possible burn opportunity. Thursday: Mostly sunny, with a high near 87. Friday: Mostly sunny, with a high near 89. Saturday: Sunny, with a high near 92. Sunday: Sunny, with a high near 95. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. From willamette-fcst at listsmart.osl.state.or.us Mon Aug 9 11:50:49 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Mon, 09 Aug 2010 13:50:49 -0500 Subject: [willamette-fcst] Silverton Hills Forecast - Mon, Aug 09 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PDT MON AUG 09 2010 BURN ADVISORY: Agricultural burning burning is not recommended. Prep burning is allowed from 12:00pm to 2:00pm with a 50 acre limit. Propane flaming is allowed up until 5:00pm. WEATHER DISCUSSION: A persistant broad upper trough remains over the Pacific Northwest this morning. Computer models indicate a disturbance now over British Columbia will drop southward during the day today to deepen the trough. Cooler air aloft witht his disturbance will allow mixing heights to approach 5000 feet by this afternoon. Our latest surface analysis shows high pressure offshore and a low in central Washington. Unfortunately the gradient stacking to the east has increased. Central Oregon pressures have fallen late morning and central Willamette Valley pressures have risin slightly. With some sunshine this afternoon temperatures in the valley should increase and pressures drop to help smooth the pressure gradient from coast to central Oregon. We will monitor gradients throughout the afternoon. Computer model forecasts indicate a northwesterly transport wind this afternoon, likely coming around enough to allow smoke evacuation to the east of the valley. The wind pattern is such that the Santiam River Canyon will be vulnerable to smoke, however. Models also indicate that winds will become more northerly during the early evening hours suggesting that the window of opportunity will close by about 5:00pm. Expect partial clearing this afternoon. Salem's high temperature today will be near 79. Relative humidity drops to 50% by 11am. Minimum relative humidity 35%. Sunset tonight: 8:22 pm. THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 66 76 79 71 Relative Humidity: 58% 39% 35% 46% Surface Wind Direction: 360 320 310 290 Surface Wind Speed: 6 7 9 8 Transport Wind Direction: 350 320 310 300 Transport Wind Speed: 3 5 7 10 Estimated Mixing Height: 2900 4100 4900 1000 Ventilation Index: 9 20 34 10 EXTENDED DISCUSSION: The upper level disturbance dropping southward from BC today will carve out an upper level low over the Pacific Northwest by tonight. This low could produce some showers on Tuesday, wetting fields and eleminating any burn opportunity. Wednesday, however, the low should drift east and there is potential for some burning during the afternoon. As the low continues to drift eastward a strong upper high noses in from the Pacific Ocean and into southern BC giving northeasterly flow aloft and much warmer temperatures for the end of the week and the weekend. EXTENDED FORECAST: Tuesday: Partly sunny but a chance for showers. High 73. Wind NNW 5-8. Wednesday: Partly sunny, high 79. Afternoon winds NW 4-7. Possible burn opportunity. Thursday: Mostly sunny, with a high near 87. Friday: Mostly sunny, with a high near 89. Saturday: Sunny, with a high near 92. Sunday: Sunny, with a high near 95. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. From willamette-fcst at listsmart.osl.state.or.us Tue Aug 10 08:35:00 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Tue, 10 Aug 2010 10:35:00 -0500 Subject: [willamette-fcst] Silverton Hills Forecast - Tue, Aug 10 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT TUE AUG 10 2010 BURN ADVISORY: Agricultural burning burning is not recommended. Prep burning is allowed from 12:00pm to 2:00pm with a 50 acre limit. Propane flaming is allowed from 12:00pm to 5:00pm. WEATHER DISCUSSION: Satellite pictures show clouds covering virtually all of the Willamette Valley again this morning. The clouds do not appear to be quite as thick as yesterday, however the top of the moist layer is at about 4100 feet so the clouds will be slow to burn off again today. In the upper atmosphere a trough extends from central British Columbia to northwestern California. This will develop into a cut-off low aloft that will drift across eastern Washington today. Moisture is limited with this feature, however as impulses rotate around the low across western Washington and northwest Oregon there could be some light showers. The morning Salem sounding showed two inversions in the lower atmosphere, one between about 1900 and 2500 feet and another between about 3900 and 4800 ft. The higher inversion will likely not mix out and will be the limit on maximum mixing heights today. Onshore gradients have weakened since yesterday. The 8:00am Newport to Redmond pressure difference was 3.5mb onshore. 2.6mb of that was from Salem to Redmond, so gradient stacking to the east continues. Forecast models indicate that transport winds in the Valley today will remain north-northwesterly, never getting more westerly than about 340 degrees. This should be confirmed with pibal soundings this afternoon, but the possibility of open field burning today looks low. Expect cloudy skies this morning and mostly cloudy skies this afternoon. Salem's high temperature today will be near 74. Relative humidity drops to 50% by 1pm. Minimum relative humidity today will be near 41%. Sunset tonight: 8:20 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 65 71 74 69 Relative Humidity: 60% 47% 41% 51% Surface Wind Direction: 340 280 310 290 Surface Wind Speed: 2 5 8 7 Transport Wind Direction: 340 340 340 320 Transport Wind Speed: 3 5 5 3 Estimated Mixing Height: 2100 4000 4500 1000 Ventilation Index: 6 20 22 3 EXTENDED DISCUSSION: The upper level low will drift across eastern Washington today and into Idaho by Thursday. A ridge of high pressure now in the eastern Pacific will intensify and move closer to the Pacific Northwest for dramatic warming later in the week. Expect hot weather for the weekend. Burning opportunities will be limited. EXTENDED FORECAST: Wednesday: Partly sunny, with a high near 80. Calm wind becoming northwest between 4 and 7 mph. Thursday: Mostly sunny, with a high near 86. Calm wind becoming north between 6 and 9 mph. Friday: Sunny, with a high near 92. Friday Night: Mostly clear, with a low around 52. Saturday: Sunny and hot, with a high near 97. Sunday: Sunny, with a high near 95. Monday: Sunny, with a high near 86. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. From willamette-fcst at listsmart.osl.state.or.us Tue Aug 10 11:39:33 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Tue, 10 Aug 2010 13:39:33 -0500 Subject: [willamette-fcst] Silverton Hills Forecast - Tue, Aug 10 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00PM PDT TUE AUG 10 2010 BURN ADVISORY: Agricultural burning burning is not recommended. Prep burning is allowed up until 2:00pm with a 50 acre limit. Propane flaming is allowed up until 5:00pm. WEATHER DISCUSSION: Satellite pictures still show clouds covering virtually all of the Willamette Valley as of late morning. Thinning of the cloud deck that was visible at this time yesterday is not evident today. A trough in the upper atmosphere extends from central British Columbia to northwestern California. This is developing into a cut-off low aloft that will drift across eastern Washington this afternoon and tonight. Moisture is limited with this feature, however as impulses rotate around the low across western Washington and northwest Oregon there could be some light showers. Some very light radar echoes are visible in Yamhill and Polk Counties as of late morning. The morning Salem sounding showed an inversion between about 3900 and 4800 ft which will be the limit on maximum mixing heights today. Onshore gradients have increased through the morning hours. The 11:00am Newport to Redmond pressure difference was 4.5mb onshore. 3.6mb of that was from Salem to Redmond, so gradient stacking to the east continues. Forecast models continue to indicate that transport winds in the Valley today will remain north-northwesterly, never getting more westerly than about 340 degrees. 1:00pm pibal soundings are scheduled to confirm the unfavorable wind direction. The possibility of open field burning today looks low. Expect mostly cloudy skies this afternoon. Salem's high temperature today will be near 74. Relative humidity drops to 50% by 1pm. Minimum relative humidity today will be near 41%. Sunset tonight: 8:20 pm THREE-HOURLY DATA: 2pm 5pm 8pm Temperature: 68 72 67 Relative Humidity: 55% 46% 59% Surface Wind Direction: 310 310 310 Surface Wind Speed: 6 8 7 Transport Wind Direction: 340 340 320 Transport Wind Speed: 5 5 3 Estimated Mixing Height: 4000 4500 1000 Ventilation Index: 20 22 3 EXTENDED DISCUSSION: The upper level low will drift across eastern Washington today and into Idaho by Thursday. A ridge of high pressure now in the eastern Pacific will intensify and move closer to the Pacific Northwest for dramatic warming later in the week. Expect hot weather for the weekend. Burning opportunities will be limited. EXTENDED FORECAST: Wednesday: Partly sunny, with a high near 80. Calm wind becoming northwest between 4 and 7 mph. Thursday: Mostly sunny, with a high near 86. Calm wind becoming north between 6 and 9 mph. Friday: Sunny, with a high near 92. Friday Night: Mostly clear, with a low around 52. Saturday: Sunny and hot, with a high near 97. Sunday: Sunny, with a high near 95. Monday: Sunny, with a high near 86. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. From willamette-fcst at listsmart.osl.state.or.us Wed Aug 11 08:28:54 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 11 Aug 2010 10:28:54 -0500 Subject: [willamette-fcst] Silverton Hills Forecast - Wed, Aug 11 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT WED AUG 11 2010 BURN ADVISORY: Agricultural burning burning is not recommended. Prep burning is allowed from 11:00am to 2:00pm with a 50 acre limit. Propane flaming is allowed from 11:00am to 5:00pm. WEATHER DISCUSSION: Upper air charts show a low pressure area, centered over about Pendleton, covering most of the Pacific Northwest this morning. With counter-clockwise flow around this low, the winds aloft over the Willamette Valley are northerly. These northerly winds extend to the surface as well. Early morning wind readings from the new Salem sodar show light north-northwest winds from the surface to 1500 feet. The morning ODF surface analysis shows high pressure offshore, a weak thermal trough in California and a weak trough in southeast Washington. Pressure gradients are onshore with a total of 2.8mb from Newport to Redmond. Newport to Salem is 1.2mb onshore and the gradient from Salem to Redmond is 1.6. Thus there is very little gradient stacking to the east this morning and it looks like there will not be a gradient stacking issue this afternoon. The limitation on burning today will be wind direction. Models show winds generally northerly with just a brief shift to about 330 this afternoon. 330 degrees is not enough westerly to do much open field burning. We will monitor winds with both pibals and the new sodar (sound detection and ranging) unit temporarily installed near the intersection of Hawthorne and State street in Salem. If an opportunity opens up it will likely be brief with only limited acerage. Expect cloudy skies this morning, breaking up by late morning, and becoming mostly sunny this afternoon. Salem's high temperature today will be near 80. Relative humidity drops to 50% by noon. Minimum relative humidity today will be near 34%. Sunset tonight: 8:19 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 69 76 80 74 Relative Humidity: 57% 42% 34% 43% Surface Wind Direction: 350 330 340 290 Surface Wind Speed: 5 6 7 6 Transport Wind Direction: 350 350 330 320 Transport Wind Speed: 3 4 9 5 Estimated Mixing Height: 2800 3800 4800 1000 Ventilation Index: 8 15 43 5 EXTENDED DISCUSSION: We are still on track for hot weather over the weekend. Temperatures will jump several degrees today with a similar jump tomorrow and again Friday. The upper level low currently centered over SE Washington and NE Oregon will shift eastward allowing an upper level high to build to the west. This will leave the region under a dry northerly or northeasterly flow through the weekend. Temperatures will be in the 90's by Friday and highs will remain in the 90's through Monday. There do not appear to be any significant burn opportunities through the next 5 days. EXTENDED FORECAST: Thursday: Mostly sunny, 86. Calm wind becoming NNW 8-11 mph. Friday: Sunny, 92. Calm wind becoming NNE 5-8 mph. Saturday: Sunny and hot, with a high near 96. Sunday: Sunny, with a high near 92. Monday: Sunny, with a high near 91. Tuesday: Mostly sunny, with a high near 83. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. From willamette-fcst at listsmart.osl.state.or.us Wed Aug 11 08:44:14 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 11 Aug 2010 10:44:14 -0500 Subject: [willamette-fcst] Silverton Hills Forecast - Wed, Aug 11 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT WED AUG 11 2010 - Correction to Ag Burn Times BURN ADVISORY: Recommended burn times for agricultural burning are from 1:00pm to 6:30pm. Prep burning is allowed from 11:00am to 2:00pm with a 50 acre limit. Propane flaming is allowed from 11:00am to 5:00pm. WEATHER DISCUSSION: Upper air charts show a low pressure area, centered over about Pendleton, covering most of the Pacific Northwest this morning. With counter-clockwise flow around this low, the winds aloft over the Willamette Valley are northerly. These northerly winds extend to the surface as well. Early morning wind readings from the new Salem sodar show light north-northwest winds from the surface to 1500 feet. The morning ODF surface analysis shows high pressure offshore, a weak thermal trough in California and a weak trough in southeast Washington. Pressure gradients are onshore with a total of 2.8mb from Newport to Redmond. Newport to Salem is 1.2mb onshore and the gradient from Salem to Redmond is 1.6. Thus there is very little gradient stacking to the east this morning and it looks like there will not be a gradient stacking issue this afternoon. The limitation on burning today will be wind direction. Models show winds generally northerly with just a brief shift to about 330 this afternoon. 330 degrees is not enough westerly to do much open field burning. We will monitor winds with both pibals and the new sodar (sound detection and ranging) unit temporarily installed near the intersection of Hawthorne and State street in Salem. If an opportunity opens up it will likely be brief with only limited acerage. Expect cloudy skies this morning, breaking up by late morning, and becoming mostly sunny this afternoon. Salem's high temperature today will be near 80. Relative humidity drops to 50% by noon. Minimum relative humidity today will be near 34%. Sunset tonight: 8:19 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 69 76 80 74 Relative Humidity: 57% 42% 34% 43% Surface Wind Direction: 350 330 340 290 Surface Wind Speed: 5 6 7 6 Transport Wind Direction: 350 350 330 320 Transport Wind Speed: 3 4 9 5 Estimated Mixing Height: 2800 3800 4800 1000 Ventilation Index: 8 15 43 5 EXTENDED DISCUSSION: We are still on track for hot weather over the weekend. Temperatures will jump several degrees today with a similar jump tomorrow and again Friday. The upper level low currently centered over SE Washington and NE Oregon will shift eastward allowing an upper level high to build to the west. This will leave the region under a dry northerly or northeasterly flow through the weekend. Temperatures will be in the 90's by Friday and highs will remain in the 90's through Monday. There do not appear to be any significant burn opportunities through the next 5 days. EXTENDED FORECAST: Thursday: Mostly sunny, 86. Calm wind becoming NNW 8-11 mph. Friday: Sunny, 92. Calm wind becoming NNE 5-8 mph. Saturday: Sunny and hot, with a high near 96. Sunday: Sunny, with a high near 92. Monday: Sunny, with a high near 91. Tuesday: Mostly sunny, with a high near 83. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. From willamette-fcst at listsmart.osl.state.or.us Wed Aug 11 11:48:45 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 11 Aug 2010 13:48:45 -0500 Subject: [willamette-fcst] Silverton Hills Forecast - Wed, Aug 11 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT WED AUG 11 2010 BURN ADVISORY: Recommended burn times for agricultural burning are from 1:00pm to 6:30pm. Prep burning is allowed up until 2:00pm with a 50 acre limit. Propane flaming is allowed up until 5:00pm. WEATHER DISCUSSION: An upper level low pressure area, centered over about Pendleton, covers most of the Pacific Northwest late this morning. With counter-clockwise flow around this low, the winds aloft over the Willamette Valley are northerly. Morning sodar soundings have shown some variability with winds above 2000 feet occasionally showing a westerly component but also occasionally showing an easterly component. Surface to around 2000 feet the sodar has been consistent in showing a nearly due northerly wind. The morning ODF surface analysis shows high pressure offshore, a weak thermal trough in California and a weak trough in southeast Washington. Pressure gradients as of 11am included: Newport to Salem, 2.0 mb onshore; Salem to Redmond, 2.1 mb onshore; and total onshore gradient Newport to Redmond, 4.1 mb onshore. Thus there is no issue today with "gradient stacking" to the east. The limitation on burning today will be wind direction. Models show winds generally northerly with just a brief shift to about 330 this afternoon. 330 degrees is not enough westerly to do much open field burning. A pibal sounding is scheduled for around 1pm near Stayton to establish a baseline to monitor any wind shift. Skies should become mostly sunny this afternoon and the high in Salem will be near 80. Minimum relative humidity today will be near 34%. Sunset tonight: 8:19 pm THREE-HOURLY DATA: 2pm 5pm 8pm Temperature: 75 78 72 Relative Humidity: 45% 39% 48% Surface Wind Direction: 340 340 290 Surface Wind Speed: 7 7 7 Transport Wind Direction: 350 330 320 Transport Wind Speed: 4 9 5 Estimated Mixing Height: 3800 4800 1000 Ventilation Index: 15 43 5 EXTENDED DISCUSSION: The Willamette Valley will see some hot weather this weekend. Temperatures today will be several degrees warmer than yesterday and there will be a similar jump tomorrow and again Friday. The upper level low currently centered over SE Washington and NE Oregon will shift eastward allowing an upper level high to build to the west. This will leave the region under a dry northerly or northeasterly flow through the weekend. Temperatures will be in the 90's by Friday and highs will remain in the 90's through Monday. There do not appear to be any significant burn opportunities through the next 5 days. EXTENDED FORECAST: Thursday: Mostly sunny, 86. Calm wind becoming NNW 8-11 mph. Friday: Sunny, 92. Calm wind becoming NNE 5-8 mph. Saturday: Sunny and hot, with a high near 96. Sunday: Sunny, with a high near 92. Monday: Sunny, with a high near 91. Tuesday: Mostly sunny, with a high near 83. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. From willamette-fcst at listsmart.osl.state.or.us Thu Aug 12 08:56:55 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 12 Aug 2010 10:56:55 -0500 Subject: [willamette-fcst] Silverton Hills Forecast - Thu, Aug 12 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT THU AUG 12 2010 BURN ADVISORY: Recommended burn times for agricultural burning are from 1:00pm to 6:30pm. Prep burning is allowed from 1:00pm to 5:00pm with a 50 acre limit. Propane flaming is allowed from 1:00pm to 5:00pm. WEATHER DISCUSSION: An upper-level ridge is building just offshore with a dry north-northwesterly flow aloft over western Oregon. The onshore flow is very weak this morning with satellite imagery showing low clouds only along the coast and in the extreme northern Willamette Valley. The Salem sounding showed several degrees of warming, since 24 hours ago, from just above the surface up through 10,000 feet, so high temperatures will be much warmer today. Forecast light northerly transport winds makes open burning highly unlikely this afternoon. TODAY?S FORECAST: Sunny and warmer. After reaching 81 degrees on Wednesday, Salem's high temperature today will be near 87 degrees. The mixing height will climb to 3000 feet about 2 p.m. and likely top out near 3700 feet around 5 p.m. An evening sea breeze should drop the mixing height to near 1500 feet by shortly before sunset. Surface and transport winds will be light northerly this morning, increase to 5-10 mph later this afternoon, then turn NW 5-10 mph this evening. Relative humidity will drop to 50% by noon and to near 30% around 5 p.m. The ventilation index will climb to only 22 this afternoon. Silverton area sunset tonight: 8:17 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 70 81 87 78 Relative Humidity: 55% 38% 30% 42% Surface Wind Direction: 360 350 340 290 Surface Wind Speed: 2 4 5 6 Transport Wind Direction: 360 360 360 320 Transport Wind Speed: 3 5 6 8 Estimated Mixing Height: 1900 3000 3700 1500 Ventilation Index: 6 15 22 12 EXTENDED DISCUSSION: A strong upper-level ridge of high pressure will build over the Pacific Northwest Friday through Monday with mostly clear skies and dry offshore flow boosting high temperatures to near record values. The ridge is forecast to shift east of the region during the middle of next week with the surface flow turning back onshore. That will cool temperatures back closer to normal by Wednesday and could create open burning opportunities. A strong enough trough may come onshore by late Wednesday or Thursday to produce showers or thundershowers in the Willamette Valley with temperatures falling to below normal. EXTENDED FORECAST: Friday: Sunny and very warm. NE wind 5-15 mph. 55/93 Saturday: Sunny with near-record warmth. NE wind 5-10 mph. 58/97 Sunday: Sunny with near-record warmth. Light wind. 59/98 Monday: Sunny with near-record warmth. Light wind. 61/99 Tuesday: Sunny. A little cooler. Wind becoming W 5-15 mph. 61/94 Wednesday: Partly cloudy and cooler. Wind W 5-15 mph. 56/84 Thursday: Mostly cloudy and cooler. Chance of showers. 54/75 Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist From willamette-fcst at listsmart.osl.state.or.us Thu Aug 12 09:00:36 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 12 Aug 2010 09:00:36 -0700 Subject: [willamette-fcst] Silverton Hills Forecast - Thu, August 12 2010 Message-ID: <8CD18C5BD70D6F4BB2B636295905299C8A3A9311@WPODFEXCL01.ODF.STATE.OR.US> SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT THU AUG 12 2010 BURN ADVISORY: Recommended burn times for agricultural burning are from 1:00pm to 6:30pm. Prep burning is allowed from 1:00pm to 5:00pm with a 50 acre limit. Propane flaming is allowed from 1:00pm to 5:00pm. WEATHER DISCUSSION: An upper-level ridge is building just offshore with a dry north-northwesterly flow aloft over western Oregon. The onshore flow is very weak this morning with satellite imagery showing low clouds only along the coast and in the extreme northern Willamette Valley. The Salem sounding showed several degrees of warming, since 24 hours ago, from just above the surface up through 10,000 feet, so high temperatures will be much warmer today. Forecast light northerly transport winds makes open burning highly unlikely this afternoon. TODAY'S FORECAST: Sunny and warmer. After reaching 81 degrees on Wednesday, Salem's high temperature today will be near 87 degrees. The mixing height will climb to 3000 feet about 2 p.m. and likely top out near 3700 feet around 5 p.m. An evening sea breeze should drop the mixing height to near 1500 feet by shortly before sunset. Surface and transport winds will be light northerly this morning, increase to 5-10 mph later this afternoon, then turn NW 5-10 mph this evening. Relative humidity will drop to 50% by noon and to near 30% around 5 p.m. The ventilation index will climb to only 22 this afternoon. Silverton area sunset tonight: 8:17 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 70 81 87 78 Relative Humidity: 55% 38% 30% 42% Surface Wind Direction: 360 350 340 290 Surface Wind Speed: 2 4 5 6 Transport Wind Direction: 360 360 360 320 Transport Wind Speed: 3 5 6 8 Estimated Mixing Height: 1900 3000 3700 1500 Ventilation Index: 6 15 22 12 EXTENDED DISCUSSION: A strong upper-level ridge of high pressure will build over the Pacific Northwest Friday through Monday with mostly clear skies and dry offshore flow boosting high temperatures to near record values. The ridge is forecast to shift east of the region during the middle of next week with the surface flow turning back onshore. That will cool temperatures back closer to normal by Wednesday and could create open burning opportunities. A strong enough trough may come onshore by late Wednesday or Thursday to produce showers or thundershowers in the Willamette Valley with temperatures falling to below normal. EXTENDED FORECAST: Friday: Sunny and very warm. NE wind 5-15 mph. 55/93 Saturday: Sunny with near-record warmth. NE wind 5-10 mph. 58/97 Sunday: Sunny with near-record warmth. Light wind. 59/98 Monday: Sunny with near-record warmth. Light wind. 61/99 Tuesday: Sunny. A little cooler. Wind becoming W 5-15 mph. 61/94 Wednesday: Partly cloudy and cooler. Wind W 5-15 mph. 56/84 Thursday: Mostly cloudy and cooler. Chance of showers. 54/75 Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Thu Aug 12 11:54:24 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 12 Aug 2010 13:54:24 -0500 Subject: [willamette-fcst] Silverton Hills Forecast - Thu, Aug 12 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT THU AUG 12 2010 BURN ADVISORY: Recommended burn times for agricultural burning are from 1:00pm to 6:30pm. Prep burning is allowed from 1:00pm to 5:00pm with a 50 acre limit. Propane flaming is allowed from 1:00pm to 5:00pm. WEATHER DISCUSSION: An upper-level ridge is building just offshore with a dry north-northwesterly flow aloft over western Oregon. The surface chart shows a trough extending from eastern Washington through north-central Oregon with weak northwesterly gradients across the Willamette Valley. Gradient-stacking is not an issue today with 2.0 mb onshore from Newport to Salem and just 0.7 mb onshore from Salem to Redmond. It is the overall lack of onshore flow that will likely inhibit open burning today. Midday satellite imagery shows low clouds along most of the Washington and Oregon coastlines with only minor penetration of marine clouds up the Columbia River to about St. Helens. Skies were sunny over the entire Willamette Valley with temperatures running about 2-5 degrees warmer than 24 hours ago. Transport winds are forecast to be fairly light and likely too northerly to provide adequate ventilation for open burning today. Transport winds will be monitored closely, with a pibal scheduled for 2:30 p.m. TODAY?S FORECAST: Sunny and warmer. Salem's high temperature today will be near 87 degrees. The mixing height will climb to 3000 feet about 2 p.m. and likely top out near 3700 feet around 5 p.m. An evening sea breeze should drop the mixing height to near 1500 feet by shortly before sunset. Surface and transport winds be NNW at 5-10 mph this afternoon, then turn NW 5-10 mph this evening. Relative humidity will drop to 30% around 5 p.m. The ventilation index will climb to only 22 this afternoon. Silverton area sunset tonight: 8:17 pm EXTENDED DISCUSSION: A strong upper-level ridge of high pressure will build over the Pacific Northwest Friday through Monday with mostly clear skies and dry offshore flow boosting high temperatures to well above normal. Weak disturbances are forecast to undercut the ridge and move into northern California. They might circulate enough moisture northward for a chance of afternoon thunderstorms over the southern Cascades. Otherwise, dry conditions are expected. The ridge is forecast to shift east of the region by next Wednesday with the surface flow turning back onshore. That will cool temperatures back closer to normal and could create open burning opportunities. An upper-level trough may be strong enough to produce showers or thundershowers in the Willamette Valley next Wednesday or Thursday with strong onshore flow cooling temperatures to below normal late next week. EXTENDED FORECAST: Friday: Sunny and very warm. NE wind 5-15 mph. 55/93 Saturday: Sunny with near-record warmth. NE wind 5-10 mph. 58/97 Sunday: Sunny with near-record warmth. Light wind. 59/98 Monday: Sunny with near-record warmth. Light wind. 61/99 Tuesday: Sunny. A little cooler. Wind becoming W 5-15 mph. 61/94 Wednesday: Partly cloudy and cooler. Wind W 5-15 mph. 56/84 Thursday: Mostly cloudy and cooler. Chance of showers. 54/75 Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist From willamette-fcst at listsmart.osl.state.or.us Fri Aug 13 09:20:47 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 13 Aug 2010 09:20:47 -0700 Subject: [willamette-fcst] Silverton Hills Forecast - Fri, August 13 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT FRI AUG 13, 2010 ...Fire Marshal Conditions are possible this afternoon and likely both Saturday and Sunday afternoons... BURN ADVISORY: Recommended burn times for agricultural burning are from noon to 6:30pm Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: An upper-level ridge is building just offshore with a dry north-northwesterly flow aloft over western Oregon. The surface chart shows a thermal trough building northward, from southwestern Oregon, into the Willamette Valley this morning. Satellite imagery shows low clouds along most of the immediate coastline, where the flow is still weakly onshore. However, skies are clear just inland and over the entire Willamette Valley. Gradients are already offshore this morning, from Redmond to Salem, and expected to increase this afternoon. Down-sloping northeasterly winds and a full day of August sunshine will warm valley temperatures well into the 90s, with very low humidity levels. Northeasterly transport winds are not conducive to good valley ventilation, so the prospect for any burning today is poor. The focus of today's discussion is on next week's weather. More on that in a moment... TODAY'S FORECAST: Sunny and warmer. After reaching 88 degrees on Thursday, Salem's high temperature today will be near 93 degrees. The mixing height will climb to 3000 feet about noon and likely top out near 5000 feet around 5 p.m. No evening sea breeze is expected this evening, with persistent dry offshore flow, so surface temperatures will be slow to cool. That will likely keep the mixing height above 1500 feet until about sunset. Light northerly surface winds, this morning, will turn north-northeasterly and increase to about 10 mph this afternoon. NE transport winds will increase to about 15 mph this afternoon. Relative humidity will drop to 50% by 11 a.m. and to near 21% around 5 p.m. The ventilation index will climb to 80 this afternoon. Silverton area sunset tonight: 8:16 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 76 87 93 84 Relative Humidity: 45% 29% 21% 29% Surface Wind Direction: 010 010 010 010 Surface Wind Speed: 7 8 12 8 Transport Wind Direction: 020 030 040 030 Transport Wind Speed: 7 14 16 12 Estimated Mixing Height: 2200 3800 5000 1500 Ventilation Index: 15 53 80 18 EXTENDED DISCUSSION: A strong upper-level ridge of high pressure will build over the Pacific Northwest Saturday through Monday. Sunny skies and dry offshore flow will bring near-record warmth to the Willamette Valley. A weak upper-level trough is forecast to undercut the ridge and move across northern California on Sunday, possibly bringing some thunderstorms to the southern Oregon Cascades. The ridge is forecast to peak over the region on Monday, with a stronger upper-level trough approaching the southern Oregon Coast by Tuesday. That system may circulate thundershower activity further north, along the Cascades, and should initiate a cooling trend. That may create an open burning opportunity, as early as Tuesday afternoon, with transport winds forecast to turn back onshore. The long-range models are beginning to come into agreement that the upper-level trough will come onshore Wednesday and/or Thursday. Increasing onshore flow and continued cooling may create an enhanced opportunity open burning opportunity one or both of those days. Temperatures will likely cool back to normal by Thursday. Strong onshore flow is forecast on Friday with considerable marine clouds penetrating into the Willamette Valley. Gradient-stacking may be too great for open burning by that time. EXTENDED FORECAST: Saturday: Sunny with near-record warmth. NE wind 5-10 mph. 58/97 Sunday: Sunny with near-record warmth. Light wind. 59/98 Monday: Sunny with near-record warmth. Light wind. 61/99 Tuesday: Sunny. A little cooler. Wind possibly becoming W 5-15 mph. 61/94 Wednesday: Partly cloudy and cooler. Wind W 5-15 mph. 57/87 Thursday: Partly cloudy. Slight chance of showers. 54/80 Friday: Morning clouds with afternoon clearing. 51/77 Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Fri Aug 13 11:17:59 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 13 Aug 2010 13:17:59 -0500 Subject: [willamette-fcst] Silverton Hills Forecast - Fri, Aug 13 2010 Message-ID: test message... From willamette-fcst at listsmart.osl.state.or.us Fri Aug 13 08:56:12 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 13 Aug 2010 10:56:12 -0500 Subject: [willamette-fcst] Silverton Hills Forecast - Fri, Aug 13 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT FRI AUG 13, 2010 ?Fire Marshal Conditions are possible this afternoon and likely both Saturday and Sunday afternoons? BURN ADVISORY: Recommended burn times for agricultural burning are from noon to 6:30pm Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: An upper-level ridge is building just offshore with a dry north-northwesterly flow aloft over western Oregon. The surface chart shows a thermal trough building northward, from southwestern Oregon, into the Willamette Valley this morning. Satellite imagery shows low clouds along most of the immediate coastline, where the flow is still weakly onshore. However, skies are clear just inland and over the entire Willamette Valley. Gradients are already offshore this morning, from Redmond to Salem, and expected to increase this afternoon. Down-sloping northeasterly winds and a full day of August sunshine will warm valley temperatures well into the 90s, with very low humidity levels. Northeasterly transport winds are not conducive to good valley ventilation, so the prospect for any burning today is poor. The focus of today?s discussion is on next week?s weather. More on that in a moment? TODAY?S FORECAST: Sunny and warmer. After reaching 88 degrees on Thursday, Salem's high temperature today will be near 93 degrees. The mixing height will climb to 3000 feet about noon and likely top out near 5000 feet around 5 p.m. No evening sea breeze is expected this evening, with persistent dry offshore flow, so surface temperatures will be slow to cool. That will likely keep the mixing height above 1500 feet until about sunset. Light northerly surface winds, this morning, will turn north-northeasterly and increase to about 10 mph this afternoon. NE transport winds will increase to about 15 mph this afternoon. Relative humidity will drop to 50% by 11 a.m. and to near 21% around 5 p.m. The ventilation index will climb to 80 this afternoon. Silverton area sunset tonight: 8:16 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 76 87 93 84 Relative Humidity: 45% 29% 21% 29% Surface Wind Direction: 010 010 010 010 Surface Wind Speed: 7 8 12 8 Transport Wind Direction: 020 030 040 030 Transport Wind Speed: 7 14 16 12 Estimated Mixing Height: 2200 3800 5000 1500 Ventilation Index: 15 53 80 18 EXTENDED DISCUSSION: A strong upper-level ridge of high pressure will build over the Pacific Northwest Saturday through Monday. Sunny skies and dry offshore flow will bring near-record warmth to the Willamette Valley. A weak upper-level trough is forecast to undercut the ridge and move across northern California on Sunday, possibly bringing some thunderstorms to the southern Oregon Cascades. The ridge is forecast to peak over the region on Monday, with a stronger upper-level trough approaching the southern Oregon Coast by Tuesday. That system may circulate thundershower activity further north, along the Cascades, and should initiate a cooling trend. That may create an open burning opportunity, as early as Tuesday afternoon, with transport winds forecast to turn back onshore. The long-range models are beginning to come into agreement that the upper-level trough will come onshore Wednesday and/or Thursday. Increasing onshore flow and continued cooling may create an enhanced opportunity open burning opportunity one or both of those days. Temperatures will likely cool back to normal by Thursday. Strong onshore flow is forecast on Friday with considerable marine clouds penetrating into the Willamette Valley. Gradient-stacking may be too great for open burning by that time. EXTENDED FORECAST: Saturday: Sunny with near-record warmth. NE wind 5-10 mph. 58/97 Sunday: Sunny with near-record warmth. Light wind. 59/98 Monday: Sunny with near-record warmth. Light wind. 61/99 Tuesday: Sunny. A little cooler. Wind possibly becoming W 5-15 mph. 61/94 Wednesday: Partly cloudy and cooler. Wind W 5-15 mph. 57/87 Thursday: Partly cloudy. Slight chance of showers. 54/80 Friday: Morning clouds with afternoon clearing. 51/77 Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist From willamette-fcst at listsmart.osl.state.or.us Fri Aug 13 11:54:41 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 13 Aug 2010 13:54:41 -0500 Subject: [willamette-fcst] Silverton Hills Forecast - Fri, Aug 13 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT FRI AUG 13, 2010 ?Fire Marshal Conditions are possible this afternoon and likely both Saturday and Sunday afternoons? BURN ADVISORY: Recommended burn times for agricultural burning are from now to 6:30pm Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: An upper-level ridge is building just offshore with a dry north-northwesterly flow aloft over western Oregon. The late-morning surface chart showed a thermal trough continuing to expand northward, from southwestern Oregon, into the Willamette Valley. The low-level offshore flow now extends westward to the northern Oregon coast, where skies have cleared and temperatures have jumped to near 80 degrees. Midday satellite imagery shows the marine clouds also backing off from the central coast, where the onshore flow is also reversing. Onshore flow was keeping skies clouds along the south coast. Skies are clear over the interior of western Oregon. Offshore gradients are increasing over the interior of western Oregon. As of 11 a.m. there was 2.2 mb of offshore pressure gradient between Salem and Redmond. Increasing northerly gradients, across the Willamette Valley, were already kicking winds up to near 15 mph. Midday temperatures were already near 80 degrees. Down-sloping northeasterly winds and a full day of August sunshine will warm valley temperatures well into the 90s, with very low humidity levels. Northeasterly transport winds make the prospect for open burning poor this afternoon. TODAY?S FORECAST: Sunny and warmer. Salem's high temperature today will be near 93 degrees. The mixing height is forecast to rise to 5000 feet by 5 p.m. Surface winds will turn north-northeasterly and increase to 10-15 mph this afternoon. NE transport winds will increase to about 15 mph this afternoon. Relative humidity will drop to near 21% around 5 p.m. The ventilation index will climb to 80 this afternoon. Persistent dry offshore winds will hold evening temperatures up, with the mixing height slowly lowering to about 1500 feet by sunset. Silverton area sunset tonight: 8:16 pm EXTENDED DISCUSSION (no changes from the morning forecast): A strong upper-level ridge of high pressure will build over the Pacific Northwest Saturday through Monday. Sunny skies and dry offshore flow will bring near-record warmth to the Willamette Valley. A weak upper-level trough is forecast to undercut the ridge and move across northern California on Sunday, possibly bringing some thunderstorms to the southern Oregon Cascades. The ridge is forecast to peak over the region on Monday, with a stronger upper-level trough approaching the southern Oregon Coast by Tuesday. That system may circulate thundershower activity further north, along the Cascades, and should initiate a cooling trend. That may create an open burning opportunity, as early as Tuesday afternoon, with transport winds forecast to turn back onshore. The long-range models are beginning to come into agreement that the upper-level trough will come onshore Wednesday and/or Thursday. Increasing onshore flow and continued cooling may create an enhanced opportunity open burning opportunity one or both of those days. Temperatures will likely cool back to normal by Thursday. Strong onshore flow is forecast on Friday with considerable marine clouds penetrating into the Willamette Valley. Gradient-stacking may be too great for open burning by that time. EXTENDED FORECAST: Saturday: Sunny with near-record warmth. NE wind 5-10 mph. 58/97 Sunday: Sunny with near-record warmth. Light wind. 59/98 Monday: Sunny with near-record warmth. Light wind. 61/99 Tuesday: Sunny. A little cooler. Wind possibly becoming W 5-15 mph. 61/94 Wednesday: Partly cloudy and cooler. Wind W 5-15 mph. 57/87 Thursday: Partly cloudy. Slight chance of showers. 54/80 Friday: Morning clouds with afternoon clearing. 51/77 Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist From willamette-fcst at listsmart.osl.state.or.us Mon Aug 16 08:26:43 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 16 Aug 2010 10:26:43 -0500 Subject: [willamette-fcst] Silverton Hills Forecast - Mon, Aug 16 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT MON AUG 16 2010 BURN ADVISORY: **** Fire Marshal conditions possible this afternoon **** Agricultural burning burning is not recommended. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: Hot weather continues over the Pacific Northwest today although there are signs that conditions are beginning to change. A ridge of high pressure in the upper atmosphere extends from off the Oregon coast, northward into the Yukon. The morning ODF surface anlysis shows a thermal trough extending from central California into SW Oregon, and a thermal low in the Columbia basin east of the cascades. Pressure gradients are fairly flat. The Newport to Redmond pressure difference as of 8am this morning was 0.5 mb offshore. The morning Salem sounding showed a strong surface-based inversion extending to about 3100 feet above the ground. This will just barely break today and the we expect the maximum mixing height will only climb to 3200 feet. Wind direction through the Valley will be northerly or slightly northeasterly. The Valley will be close to Fire Marshal Burn Ban conditions this afternoon for temperature and humidity. (Ninety-five degrees and less than 30 percent humidity is the criterion that is reachable this afternoon.) Expect sunny weather today. Salem's high temperature today will be near 95. Relative humidity drops to 50% by 10am. Minimum relative humidity 22%. Sunset tonight: 8:11 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 78 89 95 86 Relative Humidity: 43% 29% 22% 32% Surface Wind Direction: 010 350 350 310 Surface Wind Speed: 6 6 7 6 Transport Wind Direction: 360 010 010 010 Transport Wind Speed: 4 6 8 5 Estimated Mixing Height: 1800 2800 3200 1000 Ventilation Index: 7 17 26 5 EXTENDED DISCUSSION: The upper ridge will slowly weaken and eventually be undercut by an upper level low moving eastward from the Pacific Ocean into northern California. As the upper air pattern changes surface pressure patterns will change as well and a northwesterly or west-northwesterly transport wind should develop tomorrow for a possible burn opportunity. Onshore flow should continue through the week with temperatures dropping to near or slightly below average for this time of year. This will also lead to a morning cloud-afternoon sunshine pattern. EXTENDED FORECAST: Tomorrow: Sunny, with a high near 92. Light winds early becoming WNW 6-8 during the afternoon. Possible burn opportunity. Wednesday: Sunny, with a high near 82. Light winds becoming NW 5-8. Thursday: Brief morning clouds then sunny, with a high near 81. Friday: Brief morning clouds then sunny, with a high near 76. Saturday: Partly sunny, with a high near 76. Sunday: Partly sunny, with a high near 77. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. From willamette-fcst at listsmart.osl.state.or.us Mon Aug 16 11:38:26 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 16 Aug 2010 13:38:26 -0500 Subject: [willamette-fcst] Silverton Hills Forecast - Mon, Aug 16 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT MON AUG 16 2010 BURN ADVISORY: ***** Fire Marshal Burn Ban conditions possible this afternoon *** Agricultural burning burning is not recommended. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: Hot weather continues over the Pacific Northwest today although there are signs that conditions are beginning to change. A ridge of high pressure in the upper atmosphere extends from off the Oregon coast, northward into the Yukon. The latest surface analysis shows a thermal trough from the central valley of California, through southwest Oregon then into the central Willamette Valley. The thermal trough axis then extends east of the Cascades into the Columbia basin. The 11am pressure gradients showed 1.6mb onshore Newport to Salem, but 1.2 mb easterly from Redmond to Salem. Temperatures as of late morning were running 2 to 3 degrees warmer than yesterday at the same time. The morning Salem sounding showed a strong surface-based inversion extending to about 3100 feet above the ground. This will just barely break today and the maximum mixing height will only climb to about 3200 feet. Wind direction through the Valley will be northerly or slightly northeasterly. The Valley will be close to Fire Marshal Burn Ban conditions this afternoon for temperature and humidity. (Ninety-five degrees and less than 30 percent humidity is the criterion that is reachable this afternoon.) Expect sunny weather today. Salem's high temperature today will be near 95. Relative humidity drops to 50% by noon. Minimum relative humidity 22%. Sunset tonight: 8:11 pm THREE-HOURLY DATA: 2pm 5pm 8pm Temperature: 87 95 84 Relative Humidity: 33% 23% 35% Surface Wind Direction: 350 340 300 Surface Wind Speed: 5 6 6 Transport Wind Direction: 010 010 010 Transport Wind Speed: 6 8 5 Estimated Mixing Height: 6000 7000 1000 Ventilation Index: 36 56 5 EXTENDED DISCUSSION: The upper ridge will slowly weaken and eventually be undercut by an upper level low moving eastward from the Pacific Ocean into northern California. At the same time a short wave moving across the Gulf of Alaska will suppress the ridge. As the upper air pattern changes surface pressure patterns will change as well and a northwesterly or west-northwesterly transport wind should develop tomorrow for a possible burn opportunity. Onshore flow should continue through the week with temperatures dropping to near or slightly below average for this time of year. This will also lead to a morning cloud-afternoon sunshine pattern. EXTENDED FORECAST: Tomorrow: Sunny, with a high near 92. Light winds early becoming WNW 6-8 during the afternoon. Possible burn opportunity. Wednesday: Sunny, with a high near 82. Light winds becoming NW 5-8. Thursday: Brief morning clouds then sunny, with a high near 81. Friday: Brief morning clouds then sunny, with a high near 76. Saturday: Partly sunny, with a high near 76. Sunday: Partly sunny, with a high near 77. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. jlwx1608101138 From willamette-fcst at listsmart.osl.state.or.us Tue Aug 17 08:39:35 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 17 Aug 2010 10:39:35 -0500 Subject: [willamette-fcst] Silverton Hills Forecast - Tue, Aug 17 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT TUE AUG 17 2010 BURN ADVISORY: Agricultural burning burning is not recommended. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: One more hot day before a marine push kicks in overnight. Lots going on weather-wise this morning as we get set to transition out of the hot weather that has affected the Willamette Valley the past several days. In the upper atmosphere the ridge of high pressure that had been over the area is being undercut by a minor disturbance moving down the BC coast. At the same time an upper level low pressure area is evident off the northern California/SW Oregon coastline. Our lightning detection network indicates that this low is already producing thunderstorms offshore. The morning ODF surface analysis showes a well developed thermal trough from the central Valley of California, into SW Oregon and then into the southern Willamette Valley. From there the axis of the trough extends up the east side of the valley then bends over to near Hermiston and finally extends northward into eastern Washington. Pressure gradients as of 8am included: Newport to Salem, 2.5 mb onshore; and Redmond to Salem, 1.5 mb offshore. The morning Salem sounding showed a strong surface based inversion up to about about 1000 feet above ground level. In addition there were two inversions aloft, one from 2000 feet to 2800 feet, and another from 5000 feet to about 6200 feet. The lower inversions should mix out late this afternoon, but the higher inversion will likely still be there this afternoon. As the thermal trough shifts east we should get a favorable west to east pressure pattern for burning. Models indicate a marine push later today. Various models put the onset of west winds anytime from about 4pm to about 8pm tonight. In addition, forecast model soundings indicate that the push will initially be quite shallow with the low level west winds not deepening to above about 2000 feet until after sunset tonight. Winds above this shear level will be northerly. Complicating all of this is the upper low off the southwest coast. As it moves closer, some convection is likely over SW Oregon and the southern Cascades. This will have to be monitored closely since thunderstorms moving farther north...either into the Willamette Valley or over the central Cascades...will have an effect on winds and pressure patterns. Bottom line: it is a complex situation developing, but there may be a short window of opportunity late this afternoon/early this evening for some open field burning. We will keep track of all of this and monitor the winds with pibals this afternoon. Salem's high temperature today will be near 93. Relative humidity drops to 50% by 10am. Minimum relative humidity 27%. Sunset tonight: 8:09 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 80 91 93 77 Relative Humidity: 45% 31% 27% 45% Surface Wind Direction: 280 310 270 260 Surface Wind Speed: 3 5 6 6 Transport Wind Direction: 030 360 320 280 Transport Wind Speed: 5 5 8 11 Estimated Mixing Height: 1500 2500 4000 100 Ventilation Index: 8 12 32 1 EXTENDED DISCUSSION: Temperatures will be much cooler during the coming days. Longer range computer models show troughiness over the eastern Pacific Ocean and a cooler southwesterly flow aloft. Tomorrow will be the first day after a marine push which is generally not a good day to burn. However, westerly winds continue on Thursday and if mixing heights cooperate there may be a burn opportunity then. Later this week and over the weekend we should be generally in a morning cloud, afternoon sunshine pattern. EXTENDED FORECAST: Wednesday: Mostly sunny, with a high near 80. Afternoon winds NW 4-7. Thursday: Sunny, with a high near 79. Wind WNW 4-8. Friday: Sunny, with a high near 76. Saturday: Partly sunny, with a high near 74. Sunday: Partly sunny, with a high near 74. Monday: Mostly sunny, with a high near 80. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. jlwx:170810:0839 From willamette-fcst at listsmart.osl.state.or.us Tue Aug 17 11:34:25 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 17 Aug 2010 13:34:25 -0500 Subject: [willamette-fcst] Silverton Hills Forecast - Tue, Aug 17 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT TUE AUG 17 2010 BURN ADVISORY: Agricultural burning burning is not recommended. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: A somewhat complicated weather pattern today as we transition out of the hot weather that has affected the Willamette Valley the past several days. In the upper atmosphere the ridge of high pressure that had been over the area is being undercut by a minor disturbance moving down the BC coast. At the same time an upper level low pressure area is approaching Oregon from the southwest. Our lightning detection network indicates that this low is already producing thunderstorms offshore and a narrow band of convection is moving north over the Coast Range as of late morning. The ODF surface analysis showes a well developed thermal trough from the central Valley of California, into SW Oregon and then into the southern Willamette Valley. From there the axis of the trough extends up the east side of the valley then bends over to near Hermiston and finally extends northward into eastern Washington. Pressures have been falling in Redmond and as of 11am the Newport to Salem gradient has risin to 3.6mb onshore, while the Redmond to Salem gradient has fallen to just 0.7mb offshore. The morning Salem sounding showed several inversion layers. These should all mix out up to about 4000 feet this afternoon. Temperatures late this morning were running about 5 to 8 degrees warmer than at the same time yesterday. As the thermal trough continues to shift east we should get a favorable west to east pressure pattern for burning. Models indicate a marine push later today. Latest model runs are still not converging on a timing estimate for a shift to westerly winds. It still looks like sometime late this afternoon. Complicating all of this is the upper low off the southwest coast. As it moves closer, some convection is likely over SW Oregon and the southern Cascades. This will have to be monitored closely since thunderstorms moving farther north...either into the Willamette Valley or over the central Cascades...will have an effect on winds and pressure patterns. It still looks like a reasonable chance for at least some burning late today, but pibals and careful monitoring of weather conditions will determine when. Growers should be ready to move quickly if a burn window opens up. Salem's high temperature today will be near 93. Relative humidity drops to 50% by 10am. Minimum relative humidity 26%. Sunset tonight: 8:09 pm THREE-HOURLY DATA: 2pm 5pm 8pm Temperature: 91 93 76 Relative Humidity: 30% 26% 45% Surface Wind Direction: 330 290 260 Surface Wind Speed: 6 8 7 Transport Wind Direction: 360 320 280 Transport Wind Speed: 5 8 11 Estimated Mixing Height: 2500 4000 100 Ventilation Index: 12 32 1 EXTENDED DISCUSSION: Temperatures will be much cooler during the coming days. Longer range computer models show troughiness over the eastern Pacific Ocean and a cooler southwesterly flow aloft. Tomorrow will be the first day after a marine push which is generally not a good day to burn. However, westerly winds continue on Thursday and if mixing heights cooperate there may be a burn opportunity then. Later this week and over the weekend we should be generally in a morning cloud, afternoon sunshine pattern. EXTENDED FORECAST: Wednesday: Mostly sunny, with a high near 80. Afternoon winds NW 4-7. Thursday: Sunny, with a high near 79. Wind WNW 4-8. Friday: Sunny, with a high near 76. Saturday: Partly sunny, with a high near 74. Sunday: Partly sunny, with a high near 74. Monday: Mostly sunny, with a high near 80. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. jlwx:170810:1134 From willamette-fcst at listsmart.osl.state.or.us Wed Aug 18 11:42:07 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 18 Aug 2010 13:42:07 -0500 Subject: [willamette-fcst] Silverton Hills Forecast - Wed, Aug 18 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT WED AUG 18 2010 BURN ADVISORY: Agricultural burning burning is not recommended. Prep burning is allowed from 2:00pm to 5:00pm with a 50 acre limit. Propane flaming is allowed from 2:00pm to 5:00pm. WEATHER DISCUSSION: Yesterday's impressive marine push has cooled temperatures considerably in the Willamette Valley. Temperatures as of 11am were running 16 to 24 degrees cooler than yesterday at the same time. Clouds still cover most of the Valley, but satellite pictures show some breaks and we will see more sunshine this afternoon. The morning Salem sounding showed cooler temperatures at all levels from the surface to above 14,000 feet. There is a significant stable layer from about 1800 feet to about 6200 feet. Much of that stable layer will be eroded from the bottom by daytime heating, but subsiding air aloft will hold smoke from evacuating over the Cascades. There is considerable gradient stacking to the east today with the Newport to Salem pressure difference 0.9mb onshore and the Salem to Redmond gradient has risin to 3.2mb onshore as of 11am. The gradient stacking is associated with the subsidence mentioned above. The gradient stacking issue should continue all day. That continued gradient stacking associated with the downward vertical air movement (or subsidence) over the Cascades will preclude open field burning today. Expect slow clearing during the early afternoon, with mostly sunny skies by later this afternoon. Salem's high temperature today will be near 79. Relative humidity drops to 50% by noon. Minimum relative humidity 38%. Winds will be westerly generally 5-8 mph. Sunset tonight: 8:08 pm THREE-HOURLY DATA: 2pm 5pm 8pm Temperature: 71 78 71 Relative Humidity: 53% 40% 53% Surface Wind Direction: 290 300 280 Surface Wind Speed: 5 6 7 Transport Wind Direction: 280 300 280 Transport Wind Speed: 5 6 5 Estimated Mixing Height: 2900 3900 800 Ventilation Index: 14 23 4 EXTENDED DISCUSSION: Longer range upper air forecast charts show a generally west to east flow across the eastern Pacific, gradually sagging off the coast for an upper level trough that will not move through until after the weekend. This is a pattern that will produce late night and morning marine clouds in the Valley with afternoon sun and temperatures generally around average for this time of year. Westerly winds tomorrow could produce a burn opportunity if the gradient stacking and subsidence eases. EXTENDED FORECAST: Thursday: Mostly sunny, with a high near 79. Wind WNW 3-8 mph. Friday: Sunny, with a high near 79. NNW wind around 7 mph. Saturday: Partly sunny, with a high near 74. Sunday: Partly sunny, with a high near 74. Monday: Mostly sunny, with a high near 80. Tuesday: Mostly sunny, with a high near 83. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. jlwx:180810:1142 From willamette-fcst at listsmart.osl.state.or.us Thu Aug 19 09:41:51 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 19 Aug 2010 09:41:51 -0700 Subject: [willamette-fcst] Silverton Hills Forecast - Thu, August 19 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT THU AUG 19, 2010 BURN ADVISORY: Agricultural burning burning is not recommended. Prep burning is allowed from 12:00pm to 2:00pm with a 50 acre limit. Propane flaming is allowed from 12:00pm to 5:00pm. WEATHER DISCUSSION: A weak west-northwesterly flow aloft increased the onshore flow overnight with satellite imagery showing marine low clouds extending inland to the crest of the Cascades and as far south as Douglas County. Skies were sunny this morning over extreme southwestern Oregon and all areas east of the Cascades. There is some gradient-stacking this morning with 0.8 mb onshore from Newport to Salem and 2.9 mb onshore from Salem to Redmond. The low clouds should give way to sunshine by midday with afternoon heating likely balancing out the onshore flow across western Oregon. Ventilation conditions will be marginal for open burning this afternoon, with transport winds forecast to have a significant northerly component. TODAY'S FORECAST: Morning clouds, then sunny and mild. After reaching 79 degrees on Wednesday, Salem's high temperature today will be near 80 degrees. The mixing height will climb to 3000 feet about noon and likely top out near 4000 feet around 5 p.m. An evening sea breeze will drop the mixing height to near 1500 feet shortly before sunset. Surface and transport winds will be NNW 5-10 mph today. Relative humidity will drop to 50% by 2 p.m. and to near 38% around 5 p.m. The ventilation index will climb to 32 this afternoon. Silverton area sunset tonight: 8:06 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 63 73 80 71 Relative Humidity: 67% 48% 38% 51% Surface Wind Direction: 340 320 330 300 Surface Wind Speed: 5 6 8 9 Transport Wind Direction: 330 340 340 320 Transport Wind Speed: 5 6 8 10 Estimated Mixing Height: 2500 3200 4000 1500 Ventilation Index: 12 19 32 15 EXTENDED DISCUSSION: The flow aloft is forecast to turn slightly more southwesterly Friday with little change in the surface pattern. Morning clouds should give way to afternoon sunshine with continued north-northwesterly transport winds. The onshore flow will strengthen over the weekend, as an upper-level trough moves inland, with temperatures falling below normal. The marine layer will deepen significantly Saturday night with a chance of drizzle or even a light shower Sunday. A flat upper-level ridge is forecast to build over the region next Monday with transport winds turning northerly and mostly sunny skies helping temperatures recover to near normal. Increasing westerly flow aloft may provide open burning opportunities next Tuesday and/or Wednesday, as transport winds turn back onshore. EXTENDED FORECAST: Friday: Mostly sunny, with a high near 78. Wind: N 5-10 mph. Friday Night: Mostly cloudy. Low near 49. Wind: NW 5-10 mph. Saturday: Partly sunny, with a high near 75. Wind: NW 5-15 mph. Sunday: Mostly cloudy. Chance of a light shower. High near 72. Monday: Mostly sunny, with a high near 83. Tuesday: Mostly sunny, with a high near 83. Wednesday: Mostly sunny. Increasing onshore flow. High near 81. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Thu Aug 19 09:48:27 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 19 Aug 2010 09:48:27 -0700 Subject: [willamette-fcst] Test message Message-ID: Test message -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Thu Aug 19 11:59:10 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 19 Aug 2010 11:59:10 -0700 Subject: [willamette-fcst] : Silverton Hills Forecast - Thu, August 19 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT THU AUG 19, 2010 BURN ADVISORY: Agricultural burning burning is not recommended. Prep burning is allowed from now to 2:00pm with a 50 acre limit. Propane flaming is allowed from now to 5:00pm. WEATHER DISCUSSION: A very weak upper-level impulse was moving onto the northern Oregon Coast late this morning and helping to maintain the onshore flow across western Oregon. Late-morning satellite imagery showing marine low clouds persisting across most areas west of the Cascade crest and north of Douglas County. Some drizzle even fell this morning along the north coast. Skies were sunny, late this morning, over extreme southwestern Oregon and all areas east of the Cascades. Gradient-stacking has increased, since earlier this morning, with 1.0 mb onshore from Newport to Salem and 4.1 mb onshore from Salem to Redmond. The western valleys may not get warm enough this afternoon to overcome that much gradient-stacking, so chances for open burning today have lowered since the morning forecast. The low cloud deck is being more stubborn today than yesterday but beginning to show signs of breaking up over the north coast range. Look for skies to clear about an hour later this afternoon than they on Wednesday. Temperatures are running a couple of degrees cooler than 24 hours ago, so the forecast high has been lowered accordingly. The low clouds should give way to sunshine by around 2 p.m. Ventilation conditions will be marginal for open burning this afternoon. Even if the gradient-stacking is overcome, which is in doubt, transport winds are forecast to have a significant northerly component. TODAY'S FORECAST: Morning clouds, then sunny and mild. After reaching 79 degrees on Wednesday, Salem's high temperature today will be near 78 degrees. The mixing height will climb to near 4000 feet around 5 p.m. An evening sea breeze will drop the mixing height to near 1500 feet shortly before sunset. Surface and transport winds will be NNW 5-10 mph today. Relative humidity will drop to 50% around 2 p.m. and to near 40% around 5 p.m. The ventilation index will climb to 32 this afternoon. Silverton area sunset tonight: 8:06 pm THREE-HOURLY DATA: 2pm 5pm 8pm Temperature: 70 77 69 Relative Humidity: 51% 40% 53% Surface Wind Direction: 320 330 300 Surface Wind Speed: 6 8 9 Transport Wind Direction: 340 340 320 Transport Wind Speed: 6 8 10 Estimated Mixing Height: 3000 4000 1500 Ventilation Index: 18 32 15 EXTENDED DISCUSSION (no changes from the morning forecast): The flow aloft is forecast to turn slightly more southwesterly Friday with little change in the surface pattern. Morning clouds should give way to afternoon sunshine with continued north-northwesterly transport winds. The onshore flow will strengthen over the weekend, as an upper-level trough moves inland. Temperatures will fall to below normal. The marine layer will deepen significantly Saturday night with a chance of drizzle or light showers on Sunday. A flat upper-level ridge is forecast to build over the region next Monday with transport winds turning northerly and mostly sunny skies helping temperatures recover to near normal. Increasing westerly flow aloft may provide open burning opportunities next Tuesday and/or Wednesday, as transport winds turn back onshore. EXTENDED FORECAST: Friday: Mostly sunny, with a high near 78. Wind: N 5-10 mph. Friday Night: Mostly cloudy. Low near 49. Wind: NW 5-10 mph. Saturday: Partly sunny, with a high near 75. Wind: NW 5-15 mph. Sunday: Mostly cloudy. Chance of light showers. High near 72. Monday: Mostly sunny, with a high near 83. Tuesday: Mostly sunny, with a high near 83. Wednesday: Mostly sunny. Increasing onshore flow. High near 81. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Thu Aug 19 12:40:20 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 19 Aug 2010 12:40:20 -0700 Subject: [willamette-fcst] No Silverton Hills Forecast Tomorrow (Friday August 20 2010) Message-ID: To All Users of the Silverton Hills Forecast: No Silverton Hills Weather Forecasts will be issued on Friday, August 20th, 2010 due to the statewide government furlough day. The forecasts will resume on Monday, August 23rd. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Mon Aug 23 08:42:10 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 23 Aug 2010 08:42:10 -0700 Subject: [willamette-fcst] Monday - Aug 23, 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT MON AUG 23 2010 BURN ADVISORY: Recommended burn times for agricultural burning are from 12:00pm to 6:00pm. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: Upper air charts show a cool trough moving east over eastern Oregon this morning with an upper ridge of high pressure building off the coast. The morning ODF surface analysis shows a thermal trough from central California extending northwestward to the SW Oregon coast. Weak surface high pressure covers the Puget Sound region. Satellite pictures showed nearly cloud-free skies over Oregon with just a few low clouds banked up against the lower west slopes of the Cascades from Multnomah County southward to Marion County. These should dissipate quickly. The morning Salem sounding showed the atmosphere had warmed considerable above about 4000 feet since yesterday, with models showing additional warming throughout the day today. This will stabililze the atmosphere and suppress mixing heights. The maximum mixing height today in the mid-Willamette Valley will likely not reach 3000 feet. Winds on the sounding were northeasterly to about 4000 feet, then northerly and finally north-northwesterly above about 8000 feet. As of 8am this morning there was a 0.9mb offshore gradient Redmond to Newport and the Portland to Medford gradient was northerly at 3.8mb. The offshore flow should increase this afternoon. Temperatures this morning were running 2-3 degrees cooler than yesterday morning, but by this afternoon high temperatures should be 6-8 degrees warmer than they were yesterday at the same time. With the low mixing heights and northeasterly transport winds today, there will likely be no open field burning this afternoon. Salem's high temperature today will be near 83. Relative humidity drops to 50% by 11am. Minimum relative humidity 24%. Sunset tonight: 7:59 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 67 77 83 77 Relative Humidity: 52% 33% 24% 32% Surface Wind Direction: 360 360 010 010 Surface Wind Speed: 5 8 12 6 Transport Wind Direction: 010 010 010 010 Transport Wind Speed: 7 11 12 5 Estimated Mixing Height: 1500 2700 2800 500 Ventilation Index: 10 30 34 2 EXTENDED DISCUSSION: The upper level ridge off the coast this morning will strengthen and move over the Oregon and Washington tomorrow for hot weather and gusty, dry offshore winds. Temperatures will be around 10-12 degrees warmer than today. Burning is not likely Tuesday. The next opportunity for open field burning may be Wednesday as the upper ridge axis moves east and marine push ends the minor warm spell. Timing is the key. If the marine push comes in too late there will be no burn opportunity. Models are inconsistent on the onset of westerly flow in the Valley some showing a burn possibility by mid-afternoon, others holding off the push until the evening, too late for burning. Thursday will be the first day after a marine push, which usually means low mixing heights and gradient stacking (subsidence aloft) to the east and thus not likely a good burn day. Friday will be partly sunny and the GFS model shows an unfavorable northerly transport flow over the region. EXTENDED FORECAST: Tuesday: Sunny, with a high near 94. Wind ENE 5-15, gusts to 20. Wednesday: Sunny, with a high near 91. E 10mph becoming NNW, possibly WNW late. Thursday: Partly sunny but chance of sprilkles. Hihg 78. (First day after a marine push) Friday: Partly sunny, 72. Saturday: Mostly cloudy, 72. Sunday: Mostly cloudy, chance of showers. High 68. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Mon Aug 23 11:56:53 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 23 Aug 2010 11:56:53 -0700 Subject: [willamette-fcst] Mon, Aug 23d 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT MON AUG 23 2010 BURN ADVISORY: Recommended burn times for agricultural burning are from Noon to 6:00pm. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: Upper air charts show a cool trough to the east of the state and moving east away from the region. An upper ridge of high pressure is building off the coast. The late morning ODF surface analysis shows a thermal trough from central California extending northwestward to just off the SW Oregon coast. Weak surface high pressure covers the Puget Sound region. As of 11am there was a .4mb offshore gradient Redmond to Newport and the Portland to Medford gradient had increased to 5.3mb. Satellite pictures show clear skies over the entire state. The morning Salem sounding showed the atmosphere had warmed considerable above about 4000 feet since yesterday, and models are showing additional warming throughout the day today. This will stabilize the atmosphere and suppress mixing heights. The maximum mixing height today in the mid-Willamette Valley will likely not reach 3000 feet. The morning sounding showed northeasterly transport winds and computer models continue to show that pattern through the afternoon and evening. Late morning temperatures were running fairly close to where they were yesterday at the same time, but high temperatures today should be 6-8 degrees warmer than yesterday. With the low mixing heights and northeasterly transport winds today, there will likely be no open field burning this afternoon. Salem's high temperature today will be near 83. Minimum relative humidity today: 24%. Sunset tonight: 7:59 pm THREE-HOURLY DATA: 2pm 5pm 8pm Temperature: 74 81 75 Relative Humidity: 36% 25% 33% Surface Wind Direction: 360 010 020 Surface Wind Speed: 10 13 7 Transport Wind Direction: 010 010 010 Transport Wind Speed: 11 12 5 Estimated Mixing Height: 2700 2800 500 Ventilation Index: 30 34 2 EXTENDED DISCUSSION: The upper level ridge off the coast this morning will strengthen and move over the Oregon and Washington tomorrow for hot weather and gusty, dry offshore winds. Temperatures will be around 10-12 degrees warmer than today. Burning is not likely Tuesday. The next opportunity for open field burning may be Wednesday as the upper ridge axis moves east and a marine push ends the minor warm spell. Timing is the key. Both the GFS and the RUC models show this as a late afternoon event which would allow for some burning. However this event is far enough in the future that we have little confidence in the exact timing of the onset of westerly, burnable winds. Thursday will be the first day after a marine push, which usually means low mixing heights and gradient stacking (subsidence aloft) to the east and thus not likely a good burn day. Friday will be partly sunny and the GFS model shows an unfavorable northerly transport flow over the region. EXTENDED FORECAST: Tuesday: Sunny, with a high near 94. Wind ENE 5-15, gusts to 20. Wednesday: Sunny, with a high near 91. E 10mph becoming NNW, possibly WNW late. Thursday: Partly sunny but chance of sprilkles. Hihg 78. (First day after a marine push) Friday: Partly sunny, 72. Saturday: Mostly cloudy, 72. Sunday: Mostly cloudy, chance of showers. High 68. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Mon Aug 23 13:35:02 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 23 Aug 2010 13:35:02 -0700 (PDT) Subject: [willamette-fcst] Test message - disregard Message-ID: Test message - disregard -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Tue Aug 24 08:26:00 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 24 Aug 2010 08:26:00 -0700 Subject: [willamette-fcst] Tue, Aug 24th, 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT TUE AUG 24 2010 BURN ADVISORY: **** Fire Marshal Burn Ban Conditions Likely This Afternoon **** Recommended burn times for agricultural burning are from 1:00pm to 4:00pm. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: An upper level ridge covers the Pacific Northwest this morning. The axis of the ridge runs from NE British Columbia, through central Oregon to near Lake Tahoe. At the surface, our morning ODF surface analysis shows a thermal trough from the central valley of California into NW California, then just offshore along the Oregon and Washington coast. There is a strong offshore pressure gradient today. The Dalles to North Bend pressure difference is about 10mb and this will produce gusty north east winds today. The morning Salem sounding showed dramatic warming at all levels. At about 3500 feet the temperature jumped from 49F yesterday morning to 71F today. Some additional warming will occur this afternoon. There was a shallow, surface based inversion to about 200 feet that will easily mix out. The sounding also showed a more significant, subsidence inversion from about 1300 feet to about 2200 feet that will not mix out. Maximum mixing heights today will likely stay below 2000 feet. The air mass is very dry and relative humidities will drop into the teens later today. It is likely that Fire Marshal conditions will be met by early afternoon. The probability of open field burning today is nil. For the mid Willamette Valley today expect sunny skies and gusty northeast winds. Salem's high temperature today will be near 95. Relative humidity drops to 50% by 9am. Minimum relative humidity this afternoon will be near 15%. Sunset tonight: 7:58 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 76 89 95 87 Relative Humidity: 33% 20% 15% 22% Surface Wind Direction: 360 360 010 340 Surface Wind Speed: 6 10-15 10-15 6 Transport Wind Direction: 360 360 350 340 Transport Wind Speed: 11 11 12 5 Estimated Mixing Height: 900 1900 1900 500 Ventilation Index: 10 21 23 2 EXTENDED DISCUSSION: The thermal trough will shift inland tomorrow then east of the Cascades late tomorrow. Timing of this shift will determine if there is a burn opportunity. Computer models suggest that this will be a late afternoon or early evening event. Of the three computer models to which we have access two show favorable winds beginning about 5pm and one shows a wind shift around 6pm. Pibals and careful monitoring of pressure gradients will be necessary tomorrow. Thursday will likely see a deep marine layer covering the valley with the possibility of some drizzle or light rain. This will be the first day after a marine push - days which generally do not produce good burning conditions. A deepening trough, now in the Gulf of Alaska will settle over the area late in the week and over the weekend. This should result in onshore flow, along with increased cloud cover and much cooler temperatures. Shortwaves will periodically swing around the base of the trough, helping to dig the trough further south and increase the thickness of the marine layer. Models suggest that the potential exists for a few rain showers over the weekend, but the timing on these would depend on when the shortwaves pass through. EXTENDED FORECAST: Wednesday: Sunny, with a high near 94. E 5-10 mph becoming NW 5-15 late. Thursday: A chance of morning drizzle then partly sunny, 75. NW 5-10 mph. Friday: Partly sunny, with a high near 73. Friday Night: Mostly cloudy, with a low around 46. Saturday: Partly sunny, with a high near 72. Sunday: Partly sunny, with a high near 70. Monday: Mostly cloudy, with a high near 73. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Tue Aug 24 11:45:29 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 24 Aug 2010 11:45:29 -0700 Subject: [willamette-fcst] Tuesday, Aug 245h, 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT TUE AUG 24 2010 BURN ADVISORY: **** Fire Marshal Burn Ban Conditions Likely This Afternoon **** Recommended burn times for agricultural burning are from 1:00pm to 4:00pm. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: In the upper atmosphere a ridge of high pressure covers the Pacific Northwest. The axis of the ridge runs from NW Alberta, through northeast Oregon to near Las Vegas. At the surface, our late morning ODF surface analysis shows a thermal trough from the central valley of California into NW California, then just along the Oregon and Washington coast. Winds at Newport, for example, have lost their easterly component and are now northerly, indicating that the thermal trough axis is likely directly over that location. The morning Salem sounding showed dramatic warming at all levels. At about 3500 feet the temperature jumped from 49F yesterday morning to 71F today. Some additional warming will occur this afternoon. The sounding showed a strong, subsidence inversion from about 1300 feet to about 2200 feet that will not mix out this afternoon. Maximum mixing heights today will likely stay below 2000 feet. The air mass is very dry and relative humidities will drop into the teens later today. It is likely that Fire Marshal conditions will be met this afternoon. We do not expect open field burning this afternoon. For the mid-Willamette Valley expect sunny skies and gusty northeast winds. Salem's high temperature today will be near 95. Minimum relative humidity this afternoon will be near 15%. Sunset tonight: 7:58 pm THREE-HOURLY DATA: 2pm 5pm 8pm Temperature: 91 97 88 Relative Humidity: 18% 14% 22% Surface Wind Direction: 360 010 340 Surface Wind Speed: 8 10 7 Transport Wind Direction: 360 350 340 Transport Wind Speed: 11 12 5 Estimated Mixing Height: 1900 1900 500 Ventilation Index: 21 23 2 EXTENDED DISCUSSION: The thermal trough will shift inland tomorrow then east of the Cascades late tomorrow. Timing of this shift will determine if there is a burn opportunity. Latest computer models continue to suggest that this will be a late afternoon or early evening event. In addition, the latest NAM model is only marginal on direction showing a mean transport wind of 310 at 7 at 5pm tomorrow. Thursday will likely see a deep marine layer covering the valley with the possibility of some drizzle or light rain. This will be the first day after a marine push - days which generally do not produce good burning conditions. A deepening trough, now in the Gulf of Alaska will settle over the area late in the week and over the weekend. This should result in onshore flow, along with increased cloud cover and much cooler temperatures. Shortwaves will periodically swing around the base of the trough, helping to dig the trough further south and increase the thickness of the marine layer. Models suggest that the potential exists for a few rain showers over the weekend, but the timing on these would depend on when the shortwaves pass through. EXTENDED FORECAST: Wednesday: Sunny, with a high near 94. E 5-10 mph becoming NW 5-15 late. Thursday: A chance of morning drizzle then partly sunny, 75. NW 5-10 mph. Friday: Partly sunny, with a high near 73. Friday Night: Mostly cloudy, with a low around 46. Saturday: Partly sunny, with a high near 72. Sunday: Partly sunny, with a high near 70. Monday: Mostly cloudy, with a high near 73. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Wed Aug 25 08:47:16 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 25 Aug 2010 08:47:16 -0700 Subject: [willamette-fcst] Wed, Aug25th, 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT WED AUG 25 2010 BURN ADVISORY: Agricultural burning burning is not recommended. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: One more hot day is in store for the Willamette Valley then temperatures cool significantly for several days. Satellite pictures this morning show low clouds banked up along the coast from northern Washington to Cape Blanco Oregon. Otherwise skies are clear except for smoke from wildfires. A trail of smoke from the View Lake complex about 50 miles east of Estacada shows up nicely and is affecting the northeast portion of the Willamette Valley. The morning ODF surface analysis shows a thermal trough from the central valley of California northward through the Willamette Valley continuing into the Puget Sound. Yesterday that trough was along the coastline and late this afternoon or early this evening it will shift east of the Cascades. As the trough shifts, cooler marine air will enter the valley. At 8am this morning the Newport to Salem gradient was 1.0mb onshore while the Redmond to Salem gradient was 3.5mb offshore. Also on the weather maps this morning is a weak, summer-time cold front extending southwestward from the northern tip of Vancouver Island. This front is associated with a fairly strong (for this time of year) upper level low in the Gulf of Alaska. This front will sweep across the Willamette Valley overnight tonight to further deepen the marine layer and perhaps produce some drizzle or light rain by tomorrow morning. The morning Salem sounding shows a series of inversions from the surface to abuot 2800 feet. At balloon launch time the temperature at ground level was 60F, but the balloon reported that the temperature at 2800 feet was a much warmer 78F. Temperatures were generally 5 to 8 degrees warmer than yesterday moorning from the surface all the way to about 10,000 feet. With the strong inversion it will be difficult to get very high mixing heights. The maximum mixing height will be around 3100 feet at about 5pm this afternoon. Computer models indicate that while the thermal trough will move east of the valley late this afternoon finding a westerly component to the winds will be difficult. The RUC model shows transport winds at 320 to 330 degrees late this afternoon, while the NAM model shows transport winds between 330 and 340 degrees. The Portland WRF model is the most optimistic with respect to wind direction showing transport winds coming around to about 310 degrees at 6pm this evening. Pibals through the afternoon will determine if a burning opportunity develops ahead of the transition to cooler weather. For the mid Willamette Valley expect sunny and hot weather again today. Salem's high temperature will be near 94. Relative humidity drops to 50% by 9am. Minimum relative humidity 20%. Sunset tonight: 7:56 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 80 90 94 81 Relative Humidity: 35% 25% 20% 34% Surface Wind Direction: 010 360 320 270 Surface Wind Speed: 5 5 7 6 Transport Wind Direction: 340 340 330 290 Transport Wind Speed: 2 5 5 5 Estimated Mixing Height: 1000 2200 3100 500 Ventilation Index: 2 11 16 2 EXTENDED DISCUSSION: The upper level low in the Gulf of Alaska will drop southeastward and settle in over the Pacific Northwest through the weekend. This means cooler than average temperatures and some unsettled weather. Low level flow will be onshore. Disturbances rotating through the bottom of the trough will periodically deepen the marine layer over the valley for possible drizzle or showers. Timing of these disturbances is in doubt, but right now it looks like Friday will be mainly dry, with a better chance of precipitation later Saturday and Sunday. EXTENDED FORECAST: Thursday: Mostly cloudy, a little morning drizzle. High 79. Winds NW 7-10 mph. Calm wind becoming north northwest between 7 and 10 mph. Friday: Partly sunny, 72. NW 5-8. Saturday: Mostly cloudy, chance of showers. High 70. Sunday: Mostly cloudy, chance of showers, with a high near 70. Monday: Mostly cloudy, with a high near 73. Tuesday: Partly sunny, with a high near 74. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Wed Aug 25 11:51:33 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 25 Aug 2010 11:51:33 -0700 Subject: [willamette-fcst] Wed, Aug 25th, 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT WED AUG 25 2010 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: Hot weather again today, but a cooling trend is developing... The late morning ODF surface analysis shows a thermal trough from the central valley of California northward through the Willamette Valley. The trough is beginning to show signs of laying over in the north end of the Valley prior to a jump to east of the Cascades. Light west winds have developed through the western Columbia River Gorge. In addition, temperatures are running mostly a degree or two cooler in the north end of the valley versus yesterday at the same time. The cooling has already kicked in for coastal areas with low clouds and fog banked up against the coastline and some locations as much as 18 degrees cooler than yesterday. Pressure gradients have increased from the Newport to Salem. As of 11:00am the difference was 1.3mb onshore. The Redmond to Salem offshore gradient has decreased to 1.9mb. If present pressure trends continue the thermal trough will be east of the Cascades by about 6pm tonight. The morning Salem sounding showed a series of inversions from the surface to about 2800 feet, with the temperature at that top of the inversion 18 degrees warmer than at the bottom. With the strong inversion it will be difficult to get very high mixing heights. The maximum mixing height will be around 3100 feet at about 5pm this afternoon. Computer models indicate that while the thermal trough will move east of the valley late this afternoon finding a westerly component to the winds will be difficult. Latest computer models agree on a transport wind in the 320-330. Much more of a westerly component is necessary for optimum burning conditions. Pibals through the afternoon will determine if the models are correct or if a burning opportunity develops ahead of our transition to cooler weather. For the mid Willamette Valley expect sunny and hot weather this afternoon. Salem's high temperature will be near 94. Relative humidity will drop to 20%. Sunset tonight: 7:56 pm THREE-HOURLY DATA: 2pm 5pm 8pm Temperature: 91 97 83 Relative Humidity: 22% 18% 33% Surface Wind Direction: 360 340 270 Surface Wind Speed: 7 7 7 Transport Wind Direction: 340 340 290 Transport Wind Speed: 5 5 5 Estimated Mixing Height: 2200 3100 500 Ventilation Index: 11 16 2 EXTENDED DISCUSSION: An upper level low in the Gulf of Alaska will drop southeastward and settle in over the Pacific Northwest through the weekend. This means cooler than average temperatures and some unsettled weather. There is a cold front extending southwestward from southern British Columbia today that will sweep across the region overnight. This is fairly weak, but it will deepen the marine layer overnight and may produce some drizzle tomorrow morning. Low level flow will be onshore through the extended period. Disturbances rotating through the bottom of the trough will periodically deepen the marine layer over the valley for possible drizzle or showers. Timing of these disturbances is in doubt, but right now it looks like Friday will be mainly dry, with a better chance of precipitation later Saturday and Sunday. EXTENDED FORECAST: Thursday: Mostly cloudy, a little morning drizzle. High 79. Winds NW 7-10 mph. Calm wind becoming north northwest between 7 and 10 mph. Friday: Partly sunny, 72. NW 5-8. Saturday: Mostly cloudy, chance of showers. High 70. Sunday: Mostly cloudy, chance of showers, with a high near 70. Monday: Mostly cloudy, with a high near 73. Tuesday: Partly sunny, with a high near 74. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Thu Aug 26 08:54:40 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 26 Aug 2010 08:54:40 -0700 Subject: [willamette-fcst] Thursday, August 26th Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT THU AUG 26 2010 BURN ADVISORY: Recommended burn times for agricultural burning are from 12:00pm to 6:00pm. Prep burning is allowed from 12:00pm to 6:00pm with a 50 acre limit. Propane flaming is allowed from 12:00pm to 6:00pm. WEATHER DISCUSSION: Upper level ridge has moved off to the east this morning as an eastern Pacific trough moves into the state today. Marine push came in modestly last evening with variable low-level marine clouds along the coast and in the Coast Range. Upper level trough will continue to move into the state bringing cooler temperatures aloft. Axis of trough moves to the coast late this afternoon and then will broaden and settle over the entire state overnight tonight. Onshore pressure gradients have developed with the main gradient stacking over the Cascades and eastward. Newport to Salem is currently 2.5 mb onshore while Salem to Redmond is 5.2 mb onshore. Wind flow will increase from the W to NW today to 10 - 18 mph. Morning Salem sounding showed decent cooling aloft from yesterday's sounding. Temperature inversion is minor this morning with temperatures staying about the same from surface to 5000 ft. Thus the air mass is still quite stable. However, with cooling aloft and warming at the surface the air mass will destabilize well today with mixing heights rising to near 3000 ft by around 11 a.m. and near 5000 ft by 2 p.m. As the upper trough continues to move in today, and temperatures cool aloft, cumulus clouds should develop in the Willamette Valley and shut off heating to the lower to mid 70s this afternoon. In addition, W to NW wind flow will be on the increase. However, with gradient stacking to the east, will have exercise caution as to how much can be burned today. Mid-Willamette Valley temperatures will peak out at about 74 degrees this afternoon. Relative humidity will drop to about 50% between 11 a.m. and noon with the minimum humidity around 35% Sunset tonight: 7:54 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 68 72 73 64 Relative Humidity: 53% 41% 35% 46% Surface Wind Direction: 310 280 290 290 Surface Wind Speed: 6 7 12 11 Transport Wind Direction: 310 290 290 300 Transport Wind Speed: 8 11 14 12 Estimated Mixing Height: 3000 4800 5000 2500 Ventilation Index: 24 53 70 30 EXTENDED DISCUSSION: Upper level trough will remain over the state throughout the day tomorrow with cool, marine air over the region. Expect more marine low clouds over the Willamette Valley tomorrow than today. Mixing will be mostly good. Gradient stacking will be more over the Coast Range than the Cascades or at least even. Winds will be NW to N during the morning turning more NW'erly during the afternoon. This could produce some decent burning conditions in the afternoon. Upper level trough deepens Saturday as another disturbance moves through the flow. This trough will gradually move to the east later Saturday and through the remainder of the weekend. Mixing heights remain good but wind flow may turn a little more northerly with the most NW'erly flow occurring during the afternoon. Flat ridging moves into the state Monday and Tuesday bringing modest warming. EXTENDED FORECAST: Friday: Morning low clouds and afternoon clearing, with a high near 71. Calm wind during the morning becoming NW'erly between 8 and 12 mph during the afternoon. Friday Night: Partly to mostly cloudy, with a low around 45. NW wind between 5 and 8 mph becoming calm. Saturday: Mostly cloudy, with a high near 68. Calm wind becoming northwest between 7 and 10 mph. Saturday Night: Partly to mostly cloudy, with a low around 47. Sunday: Morning low clouds and afternoon clearing, with a high near 70. Sunday Night: Partly cloudy, with a low around 47. Monday: Morning clouds and afternoon clearing, with a high near 70. Monday Night: Mostly lear, with a low around 49. Tuesday: Mostly sunny, with a high near 74. Tuesday Night: Clear, with a low around 51. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Thu Aug 26 08:58:55 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 26 Aug 2010 08:58:55 -0700 Subject: [willamette-fcst] August 26th Update Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT THU AUG 26 2010 BURN ADVISORY: Recommended burn times for agricultural burning are from 12:00pm to 6:00pm. Prep burning is allowed from 12:00pm to 4:00pm with a 50 acre limit. Propane flaming is allowed from 12:00pm to 5:00pm. WEATHER DISCUSSION: Upper level ridge has moved off to the east this morning as an eastern Pacific trough moves into the state today. Marine push came in modestly last evening with variable low-level marine clouds along the coast and in the Coast Range. Upper level trough will continue to move into the state bringing cooler temperatures aloft. Axis of trough moves to the coast late this afternoon and then will broaden and settle over the entire state overnight tonight. Onshore pressure gradients have developed with the main gradient stacking over the Cascades and eastward. Newport to Salem is currently 2.5 mb onshore while Salem to Redmond is 5.2 mb onshore. Wind flow will increase from the W to NW today to 10 - 18 mph. Morning Salem sounding showed decent cooling aloft from yesterday's sounding. Temperature inversion is minor this morning with temperatures staying about the same from surface to 5000 ft. Thus the air mass is still quite stable. However, with cooling aloft and warming at the surface the air mass will destabilize well today with mixing heights rising to near 3000 ft by around 11 a.m. and near 5000 ft by 2 p.m. As the upper trough continues to move in today, and temperatures cool aloft, cumulus clouds should develop in the Willamette Valley and shut off heating to the lower to mid 70s this afternoon. In addition, W to NW wind flow will be on the increase. However, with gradient stacking to the east, will have exercise caution as to how much can be burned today. Mid-Willamette Valley temperatures will peak out at about 74 degrees this afternoon. Relative humidity will drop to about 50% between 11 a.m. and noon with the minimum humidity around 35% Sunset tonight: 7:54 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 68 72 73 64 Relative Humidity: 53% 41% 35% 46% Surface Wind Direction: 310 280 290 290 Surface Wind Speed: 6 7 12 11 Transport Wind Direction: 310 290 290 300 Transport Wind Speed: 8 11 14 12 Estimated Mixing Height: 3000 4800 5000 2500 Ventilation Index: 24 53 70 30 EXTENDED DISCUSSION: Upper level trough will remain over the state throughout the day tomorrow with cool, marine air over the region. Expect more marine low clouds over the Willamette Valley tomorrow than today. Mixing will be mostly good. Gradient stacking will be more over the Coast Range than the Cascades or at least even. Winds will be NW to N during the morning turning more NW'erly during the afternoon. This could produce some decent burning conditions in the afternoon. Upper level trough deepens Saturday as another disturbance moves through the flow. This trough will gradually move to the east later Saturday and through the remainder of the weekend. Mixing heights remain good but wind flow may turn a little more northerly with the most NW'erly flow occurring during the afternoon. Flat ridging moves into the state Monday and Tuesday bringing modest warming. EXTENDED FORECAST: Friday: Morning low clouds and afternoon clearing, with a high near 71. Calm wind during the morning becoming NW'erly between 8 and 12 mph during the afternoon. Friday Night: Partly to mostly cloudy, with a low around 45. NW wind between 5 and 8 mph becoming calm. Saturday: Mostly cloudy, with a high near 68. Calm wind becoming northwest between 7 and 10 mph. Saturday Night: Partly to mostly cloudy, with a low around 47. Sunday: Morning low clouds and afternoon clearing, with a high near 70. Sunday Night: Partly cloudy, with a low around 47. Monday: Morning clouds and afternoon clearing, with a high near 70. Monday Night: Mostly lear, with a low around 49. Tuesday: Mostly sunny, with a high near 74. Tuesday Night: Clear, with a low around 51. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Thu Aug 26 11:48:52 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 26 Aug 2010 11:48:52 -0700 Subject: [willamette-fcst] August 26th Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT THU AUG 26 2010 BURN ADVISORY: Recommended burn times for agricultural burning are from 12:00pm to 6:00pm. Prep burning is allowed from 12:00pm to 4:00pm with a 50 acre limit. Propane flaming is allowed from 12:00pm to 5:00pm. WEATHER DISCUSSION: Upper level ridge has moved off to the east this morning as an eastern Pacific trough moves into the state today. Upper level trough will continue to move into the state bringing cooler temperatures aloft. Axis of trough moves to the coast late this afternoon and then will broaden and settle over the entire state overnight tonight. Onshore pressure gradients have developed with the main gradient stacking over the Cascades and eastward. Gradient stacking has increased to the east with Newport to Salem at 2.9 mb onshore while Salem to Redmond is 6.6 mb onshore. Wind flow will increase from the W to NW today to 8 - 14 mph. The morning Salem sounding showed decent cooling aloft from yesterday's sounding. Temperature inversion is minor this morning with temperatures staying about the same from surface to 5000 ft. Thus the air mass started out quite stable but with cooling aloft and warming at the surface the air mass is destabilizing well with mixing heights expected to rise to near 5000 ft by 2 p.m. As the upper trough is moving in today, and temperatures are cooling aloft, clouds are developing over the northern part of the state. This will cap heating to the lower to mid 70s this afternoon. In addition, W to NW wind flow will be on the increase. However, with gradient stacking to the east, will have to exercise caution as to how much can be burned today. Mid-Willamette Valley temperatures will peak out at about 74 degrees with the relative humidity dropping to around 35%. Sunset tonight: 7:54 pm THREE-HOURLY DATA: 2pm 5pm 8pm Temperature: 72 73 64 Relative Humidity: 41% 35% 46% Surface Wind Direction: 280 290 290 Surface Wind Speed: 7 12 11 Transport Wind Direction: 290 290 300 Transport Wind Speed: 11 14 12 Estimated Mixing Height: 4800 5000 2500 Ventilation Index: 53 70 30 EXTENDED DISCUSSION: Upper level trough will remain over the state throughout the day tomorrow with cool, marine air over the region. Expect more marine low clouds over the Willamette Valley tomorrow than today. Mixing will be mostly good. Gradient stacking will be more over the Coast Range than the Cascades or at least even. Winds will be NW to N during the morning turning more NW'erly during the afternoon. This could produce some decent burning conditions in the afternoon. Upper level trough deepens Saturday as another disturbance moves through the flow. This trough will gradually move to the east later Saturday and the remainder of the weekend. Mixing heights remain good but wind flow may turn a little more northerly with the most NW'erly flow occurring during the afternoon. Another trough moves in Monday for increased cloud cover and a chance of showers which will then be followed by flat ridging for Tuesday. EXTENDED FORECAST: Friday: Morning low clouds and afternoon clearing, with a high near 71. Calm wind during the morning becoming NW'erly between 8 and 12 mph during the afternoon. Friday Night: Partly to mostly cloudy, with a low around 45. NW wind between 5 and 8 mph becoming calm. Saturday: Mostly cloudy, with a high near 68. Calm wind becoming northwest between 7 and 10 mph. Saturday Night: Partly to mostly cloudy, with a low around 47. Sunday: Morning low clouds and afternoon clearing, with a high near 70. Sunday Night: Partly cloudy, with a low around 47. Monday: Mostly cloudy with a chance of showers, with a high near 67. Monday Night: Mostly cloudy, with a low around 50. Tuesday: Morning clouds with afternoon clearing, with a high near 71. Tuesday Night: Clear, with a low around 48. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Fri Aug 27 08:38:27 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 27 Aug 2010 08:38:27 -0700 Subject: [willamette-fcst] August 27th Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT FRI AUG 27 2010 BURN ADVISORY: Recommended burn times for agricultural burning are from 11:00am to 6:00pm. Prep burning is allowed from 11:00am to 4:00pm with a 50 acre limit. Propane flaming is allowed from 11:00am to 5:00pm. WEATHER DISCUSSION: Upper level trough is firmly entrenched over the state today with higher level clouds over the region associated with the nearby jetstream. A disturbance will rotate through the flow bringing increasing clouds later today and tonight. Pressure gradients are rather flat this morning with the Newport to Salem gradient at .3mb onshore and Salem to Redmond .9mb onshore. With modest heating this afternoon pressure gradients should increase a little faster over the Coast Range than the Cascades. However, the Medford draw will be prevalent and keep winds fairly northerly today. Morning sounding showed a minor stable layer near the surface up to about 1000 ft. This will mix out with daytime heating. Mixing levels will rise nicely today with the mixing height above 4000 ft by 11 a.m. and above 5000 ft around noon. Low-level winds are rather variable up about 1500 ft then turn N to NE at 5 to 10 mph. Expect partly to mostly cloudy skies today. High temperature will rise to near 70. Relative humidity drops below 50% by 1 p.m. with the minimum near 40%. Wind flow will be light this morning, becoming NW to N at 6 - 10 mph. Will have release pibals to see whether enough NW'erly flow can be "squeezed out" for a decent burning opportunity. Sunset tonight: 7:52 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 61 68 71 65 Relative Humidity: 62% 42% 35% 50% Surface Wind Direction: 360 340 340 310 Surface Wind Speed: 5 6 8 7 Transport Wind Direction: 350 340 340 350 Transport Wind Speed: 7 10 11 12 Estimated Mixing Height: 4500 5500 6000 4000 Ventilation Index: 32 55 66 48 EXTENDED DISCUSSION: Upper level trough deepens tonight as a disturbance moves into the state overnight. This quite possibly could produce some light rain over the region on Saturday, mainly to the south. Pressure gradients will be light northerly early, then turn more onshore during the day with NW'erly flow by mid to late afternoon. Temperatures will remain cool under mostly cloudy skies and may not reach 70. Upper trough moves off to the east Sunday but skies will remain cloudy and temperatures cool. Wind flow turns more westerly. Another disturbance will ride down the back side of the trough later Sunday and Monday and bring another chance of some light rain. Wind flow will be SW'erly on Monday. Trough moves off to the east Tuesday and Wednesday with a flat ridge moving in. Temperatures will warm and the air mass will dry out. EXTENDED FORECAST: Saturday: Mostly cloudy, with a high near 69. Calm wind becoming NW'erly between 8 and 11 mph. Saturday Night: Mostly cloudy, with a low around 48. NW'erly wind between 8 and 11 mph becoming calm. Sunday: Mostly cloudy, with a high near 68. Calm wind becoming westerly between 5 and 10 mph. Sunday Night: Mostly cloudy, with a low around 47. Monday: A 30 percent chance of showers. Mostly cloudy, with a high near 67. Monday Night: A chance of showers. Mostly cloudy, with a low around 49. Tuesday: Partly sunny, with a high near 74. Tuesday Night: Mostly cloudy, with a low around 50. Wednesday Night: Partly cloudy, with a low around 52. Thursday: Mostly sunny, with a high near 82. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Nick Yonker Meteorology Manager Oregon Department of Forestry 503-945-7451 -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Fri Aug 27 11:55:30 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 27 Aug 2010 11:55:30 -0700 Subject: [willamette-fcst] August 27th - noon Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT FRI AUG 27 2010 BURN ADVISORY: Recommended burn times for agricultural burning are from now to 6:00pm. Prep burning is allowed from now to 4:00pm with a 50 acre limit. Propane flaming is allowed from now to 5:00pm. WEATHER DISCUSSION: Upper level trough is firmly entrenched over the state today with higher level clouds over the region associated with the nearby jetstream. A disturbance will rotate through the flow bringing increasing clouds tonight. Pressure gradients are rather light with the Newport to Salem gradient at .7mb onshore and Salem to Redmond 1.7mb onshore. It appears that since there is less cloud cover east of the Cascade, pressures are lowering more on the east side of the mountains, thus gradient stacking is remain to our east. In addition, the Medford draw will remain prevalent and keep winds fairly northerly today. Morning sounding showed a minor stable layer near the surface up to about 1000 ft. This has mostly mixed out due to daytime heating. Mixing levels have risen to above 5000 ft already. Low-level winds from the Portland wind profiler show due north winds at about 10 mph. Expect partly to mostly cloudy skies today. High temperature will rise to near 70. Relative humidity drops below 50% by 1 p.m. with the minimum near 38%. Wind flow is mostly northerly and appears it may remain so through most of the afternoon. Sunset tonight: 7:52 pm THREE-HOURLY DATA: 2pm 5pm 8pm Temperature: 68 71 65 Relative Humidity: 42% 38% 50% Surface Wind Direction: 350 350 330 Surface Wind Speed: 6 8 7 Transport Wind Direction: 350 350 350 Transport Wind Speed: 10 11 12 Estimated Mixing Height: 5500 6000 4000 Ventilation Index: 55 66 48 EXTENDED DISCUSSION: Upper level trough deepens tonight as a disturbance moves into the state overnight. This quite possibly could produce some light rain over the region on Saturday, mainly to the south. Pressure gradients will be light northerly early, then turn more onshore during the day with NW'erly flow by mid to late afternoon. Temperatures will remain cool under mostly cloudy skies, and may not reach 70. Upper trough moves off to the east Sunday but skies will remain cloudy and temperatures cool. Wind flow turns more westerly. Another disturbance will ride down the back side of the trough later Sunday and Monday and bring another chance of some light rain. Wind flow will be SW'erly on Monday. Trough moves off to the east Tuesday and Wednesday with a flat ridge moving in. Temperatures will warm and the air mass will dry out. EXTENDED FORECAST: Saturday: Mostly cloudy with 30 percent chance of showers, with a high near 70. Calm wind becoming NW'erly between 8 and 11 mph. Saturday Night: Mostly cloudy, with a low around 48. NW'erly wind between 8 and 11 mph becoming calm. Sunday: Mostly cloudy, with a high near 68. Calm wind becoming westerly between 5 and 10 mph. Sunday Night: Mostly cloudy, with a low around 47. Monday: A 60 percent chance of showers. Mostly cloudy, with a high near 67. Monday Night: A chance of showers. Mostly cloudy, with a low around 49. Tuesday: Partly sunny, with a high near 74. Tuesday Night: Mostly cloudy, with a low around 50. Wednesday: Mostly sunny, with a high around 80. Thursday: Mostly sunny, with a high near 82. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Mon Aug 30 08:42:11 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 30 Aug 2010 08:42:11 -0700 Subject: [willamette-fcst] Mon, Aug 30th, 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT MON AUG 30 2010 BURN ADVISORY: Recommended burn times for agricultural burning are from 9:00am to 6:00pm. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: Fall-like weather has settled in over the Pacific Northwest for the next few days. A fairly broad upper level trough extends from the Yukon, across the Pacific Northwest and southward to off the northwestern Mexican coast. Impulses rotating through this trough will keep clouds and a chance for some light rain in the forecast through mid week. Satellite pictures this morning show an area of thick clouds moving WNW to ESE across the Valley. This cloud mass has produced rain across much of the area this morning. Amounts include .11 at the Salem Airport and .15 at Jordan Valley. A weak Pacific front will move through western Oregon today followed by drying overnight prior to another disturbance which should produce similar amounts of rain tomorrow afternoon and evening. The morning Salem sounding showed a cool, moist air mass. Maximum mixing heights will reach a bit over 3000 feet this afternoon, however wet fields should preclude any open field burning today. Expect clouds, light rain and cool weather. Temperatures will be about 15 degrees below average for late August. Salem's high temperature today will be near 65. Minimum relative humidity will be about 52%. Sunset tonight: 7:47 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 59 63 65 62 Relative Humidity: 69% 56% 52% 62% Surface Wind Direction: 030 220 290 270 Surface Wind Speed: 4 4 6 5 Transport Wind Direction: 120 150 190 190 Transport Wind Speed: 10 5 5 3 Estimated Mixing Height: 2000 2800 3200 500 Ventilation Index: 20 14 16 2 EXTENDED DISCUSSION: A flat upper level ridge will begin building over the area later Wednesday for a warming and drying trend. Longer range models show this flat ridge continuing Thursday and Friday. Although the ridge will be weak there are indications that a slight offshore wind component could develop. This would allow for clearing skies and warmer weather, with temperatures back into the 80's. However, offshore winds are not favorable for open field burning. Computer models suggest that another upper level trough will move over the region sometime early in the coming weekend. Thus, any period of warming at week's end will likely be short lived. EXTENDED FORECAST: Tuesday: Mostly cloudy, 65. Increasing chance of rain late. Wind SW 5-8 mph. A Wednesday: Mostly cloudy, chance of light rain. High 70. Wind S 5. Thursday Night: Partly cloudy, with a low around 52. Friday: Mostly sunny, with a high near 82. Saturday: Mostly cloudy, 78. Sunday: Partly sunny, with a high near 77. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Tue Aug 31 08:20:50 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 31 Aug 2010 08:20:50 -0700 Subject: [willamette-fcst] Tue, 31 Aug 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT TUE AUG 31 2010 BURN ADVISORY: Recommended burn times for agricultural burning are from 10:00am to 6:00pm. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: Cloudy and wet weather likely this afternoon. Upper air charts show a broad trough covering the western US this morning. The axis of the trough is along the Canadian Rockies, through central Idaho then curving southwestward to southern California. This leaves the Pacific Northwest in a generally west-northwesterly flow aloft. This flow is steering a Pacific weather system at Washington and northwest Oregon. The morning ODF surface analysis shows a warm front just off the Washington coast, extending southward to off the Oregon coast. Rain already covers most of western Washington and it has been raining since about 6:45 this morning in Astoria. The rain will slowly spread southeastward this morning. Best estimate is for rain to reach Salem by around 10:00am and then cover most of the Willamette Valley by early afternoon. Computer models indicate over a quarter of an inch of rain by Wednesday morning. The morning Salem sounding showed that the air mass had warmed somewhat in the past 24 hours. This will keep mixing heights lower than yesterday when the maximum mixing height was about 4000 feet. Look for a maximum today of about 3500 feet. Low level winds measured this morning were southwesterly, veering to westerly by about 6000 feet above ground level. Computer models suggest that the southwesterly wind direction will continue through this afternoon. Winds and mixing heights today will be favorable for burning, but if the rain comes in on schedule then open field burning would not be an option. For the mid-Willamette valley expect clouds increasing this morning, with rain spreading in from the northwest by early afternoon. Salem's high temperature today will be near 69. Minimum relative humidity 55%. Sunset tonight: 7:45 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 61 68 69 65 Relative Humidity: 72% 57% 59% 70% Surface Wind Direction: 180 190 200 230 Surface Wind Speed: 7 7 6 7 Transport Wind Direction: 200 220 240 200 Transport Wind Speed: 12 15 18 11 Estimated Mixing Height: 2200 2800 3500 1000 Ventilation Index: 26 42 63 11 EXTENDED DISCUSSION: After Wednesday expect drier and warmer conditions as a flat upper level ridge builds over the area. Temperatures should climb to near or slightly above average for the time of year. Computer models suggest that another upper level trough will move over the area sometime early in the weekend. Moisture looks limited but temperatures will likely fall back below average for Saturday, Sunday and the Labor Day holiday. EXTENDED FORECAST: Wednesday: Mostly cloudy, showers decreasing. High 74. Wind S 5-9 becomming WNW. Thursday: Mostly sunny, with a high near 85. North wind between 3 and 10 mph. Friday: Sunny, with a high near 86. Saturday: Mostly sunny, with a high near 78. Sunday: Partly sunny, with a high near 75. Monday: Partly sunny, with a high near 76. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Tue Aug 31 11:51:24 2010 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 31 Aug 2010 11:51:24 -0700 Subject: [willamette-fcst] TUE, Aug 31st, 2010 Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT TUE AUG 31 2010 BURN ADVISORY: Recommended burn times for agricultural burning are now until 6:00pm. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: Upper air charts show a broad trough covering the western US today. The axis of the trough remains along the Canadian Rockies, through central Idaho then curving southwestward to southern California. This leaves the Pacific Northwest in a generally west-northwesterly flow aloft. This flow is steering a Pacific weather system at Washington and northwest Oregon. Rain began falling early this morning along the northern Oregon coast, and by late morning had spread to a line from Portland to McMinnville to Pacific City on the coast. Rain will likely continue to slowly spread southeastward this afternoon. The morning Salem sounding showed that the air mass had warmed somewhat in the past 24 hours. This will keep mixing heights lower than yesterday when the maximum mixing height was about 4000 feet. Look for a maximum today of about 3500 feet. Low level winds measured this morning were southwesterly, veering to westerly by about 6000 feet above ground level. Computer models suggest that the a WSW wind direction will continue through this afternoon. Winds and mixing heights today will be favorable for burning. If the rain holds off long enough there may be a window of opportunity between the time that the mixing heights reach a favorable level and the time that the rain moves in for some open field burning. As of noon the estimated mixing height is 2000 feet with the mixing height reaching 3000 feet about 3pm. Afternoon forecast for the mid-Willamette valley: expect mostly cloudy skies, an increasing chance of light rain, mainly northern sections. Salem's high temperature today will be near 69. Minimum relative humidity 55%. Sunset tonight: 7:45 pm THREE-HOURLY DATA: 2pm 5pm 8pm Temperature: 64 64 60 Relative Humidity: 60% 67% 81% Surface Wind Direction: 190 190 220 Surface Wind Speed: 11 8 8 Transport Wind Direction: 220 240 200 Transport Wind Speed: 15 18 11 Estimated Mixing Height: 2800 3500 1000 Ventilation Index: 42 63 11 EXTENDED DISCUSSION: After Wednesday expect drier and warmer conditions as a flat upper level ridge builds over the area. Temperatures should climb to near or slightly above average for the time of year. Computer models suggest that another upper level trough will move over the area sometime early in the weekend. Moisture looks limited but temperatures will likely fall back below average for Saturday, Sunday and the Labor Day holiday. EXTENDED FORECAST: Wednesday: Mostly cloudy, showers decreasing. High 74. Wind S 5-9 becomming WNW. Thursday: Mostly sunny, with a high near 85. North wind between 3 and 10 mph. Friday: Sunny, with a high near 86. Saturday: Mostly sunny, with a high near 78. Sunday: Partly sunny, with a high near 75. Monday: Partly sunny, with a high near 76. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. -------------- next part -------------- An HTML attachment was scrubbed... URL: