From willamette-fcst at listsmart.osl.state.or.us Thu Sep 1 08:54:05 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 1 Sep 2011 08:54:05 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 8:52 AM PDT THU SEP 1, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: The dry upper-level disturbance that moved across northern Oregon Wednesday afternoon was cutting across Idaho this morning. In its wake, the flow aloft has turned northerly over western Oregon, and low-level winds have turned offshore. The Salem sounding this morning revealed a much shallower and drier marine layer than 24 hours ago. Temperatures have warmed several degrees, above 2000 feet, with northeasterly winds extending from the surface up to 10,000 feet. Mid-morning visible satellite imagery showed only patchy low clouds in the extreme northern Willamette Valley and over the northern coastal region. Otherwise, skies were mostly clear across the state. The surface map shows high pressure over western Washington and northwestern Oregon, with a thermal trough beginning to build northward into southwestern Oregon. An upper-level disturbance is forecast to move across British Columbia today. Although it will stay well north of Oregon, it will retard to northward movement of the surface thermal trough into southwestern Oregon. Therefore, temperatures will warm today but stay slightly below normal. Warming aloft will lead to much lower mixing heights compared to Wednesday. NE transport winds are forecast to strengthen and back to more northerly this afternoon. TODAY'S FORECAST: Sunny and warmer. Salem's high temperature today will be near 78 degrees (normal is 80). Relative humidity drops to near 50% by noon and to 34% by 5 p.m. Surface winds: N 5-10 mph this morning; N 10-15 mph this afternoon. Transport winds: NE 10 mph this morning; NNE 15 mph this afternoon. Mixing height: Rises to 3000 feet by 2 p.m. and to near 4000 feet by 5 p.m. Salem's sunset tonight: 7:49 p.m. THREE-HOURLY DATA: 11 a.m. 2 p.m. 5 p.m. 8 p.m. Temperature: 62 71 77 70 Relative Humidity: 54% 41% 34% 44% Surface Wind Direction: 360 360 360 350 Surface Wind Speed: 5 10 12 10 Transport Wind Direction: 025 010 360 360 Transport Wind Speed: 10 12 17 17 Mixing Height: 2000 3000 4000 1500 Ventilation Index: 20 36 68 26 EXTENDED DISCUSSION: An upper-level ridge is forecast to build onshore Friday and over Oregon Saturday. Temperatures will continue to warm with highs likely climbing to near 90 by Saturday. As the ridge slides east of the state, increasing southerly flow aloft may bring isolated thunderstorms to the Cascades on Sunday. Temperatures should climb into the low 90s. The forecast weather pattern for next week is not favorable for open burning, with a broad ridge of high pressure likely staying parked over the region. Expect a continuation of dry and quite warm conditions. If the ridge shifts far enough to the east, then afternoon sea breezes could provide limited burning opportunities. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text 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: -------------- next part -------------- A non-text attachment was scrubbed... Name: Silverton Hills AM Forecast.doc Type: application/msword Size: 32256 bytes Desc: Silverton Hills AM Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Thu Sep 1 11:33:29 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 1 Sep 2011 11:33:29 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 11:30 AM PDT THU SEP 1, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: A dry north-northwesterly flow aloft will direct an upper-level disturbance across British Columbia later today and tonight. At the surface, high pressure is building into western Washington and northwestern Oregon, with northerly pressure-gradients across the Willamette Valley. Late-morning visible satellite imagery showed clear skies across western Oregon. ODF Sodar, located in the central coastal range, is showing northeasterly winds from just above the surface up to 3000 feet. That is in-line with model sounding forecasts, which show NNE transport winds increasing across the Willamette Valley this afternoon. A pibal is scheduled for 2 p.m. to verify the predicted transport winds. Sunny skies will help temperatures recover close to normal this afternoon. Warming aloft will lead to much lower mixing heights compared to Wednesday. TODAY'S FORECAST: Sunny and warmer. Salem's high temperature today will be near 78 degrees (normal is 80). Relative humidity drops to near 34% by 5 p.m. Surface winds: N 10-15 mph this afternoon. Transport winds: NNE 15 mph this afternoon. Mixing height: Rises to 3000 feet by 2 p.m. and to near 4000 feet by 5 p.m. Salem's sunset tonight: 7:49 p.m. THREE-HOURLY DATA: 2 p.m. 5 p.m. 8 p.m. Temperature: 71 77 70 Relative Humidity: 41% 34% 44% Surface Wind Direction: 360 360 350 Surface Wind Speed: 10 12 10 Transport Wind Direction: 010 360 360 Transport Wind Speed: 12 17 17 Mixing Height: 3000 4000 1500 Ventilation Index: 36 68 26 EXTENDED DISCUSSION: An upper-level ridge is forecast to build onshore Friday and over Oregon Saturday. Temperatures will warm into the low 80s Friday and to near 90 Saturday. As the ridge slides east of the state, increasing southerly flow aloft may bring isolated thunderstorms to the Cascades on Sunday, with temperatures likely reaching the low 90s. The weather pattern for next week is not favorable for open burning, with a broad ridge of high pressure forecast to remain over the region. Expect dry and quite warm conditions. If the ridge shifts far enough to the east, then afternoon sea breezes could provide limited burning opportunities, but the threat of thunderstorms would also increase. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text 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: -------------- next part -------------- A non-text attachment was scrubbed... Name: Silverton Hills Midday Forecast.doc Type: application/msword Size: 31232 bytes Desc: Silverton Hills Midday Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Fri Sep 2 08:58:18 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 2 Sep 2011 08:58:18 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 8:55 AM PDT FRI SEP 2, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: Northwesterly flow aloft is driving a dry cold front across eastern Washington, this morning. That turned pressure-gradients enough onshore to bring marine low clouds onto western Washington and the northwestern corner of Oregon. Some low clouds made it up the Columbia River into the northern Willamette Valley. Otherwise, skies were clear this morning across Oregon, with the exception of areas of wildfire smoke east of the Cascades. The surface map this morning shows high pressure building into western Washington with a weak trough extending from eastern Washington into north-central Oregon. Pressure-gradients are mostly northerly across western Oregon, in response to a thermal trough building into southwestern Oregon. The Salem sounding this morning showed a few degrees of warming throughout the lower atmosphere. Winds were northeasterly below 3000 feet; backing to northwesterly aloft. Patchy morning low clouds should quickly give way to sunshine today, as an upper-level ridge of high pressure builds onshore. Surface and transport winds are forecast to be north to northeasterly and increase this afternoon. Slightly warmer air aloft will generally keep maximum mixing heights at or below 4000 feet, with high temperatures climbing into the low 80s. TODAY'S FORECAST: Patchy morning clouds, then sunny with near-normal temperatures. Salem's high temperature today will be near 81 degrees (normal is 80). Relative humidity drops to below 50% by 11 a.m. and to near 30% by 5 p.m. Surface winds: N 5-10 mph this morning; NNE 10-15 mph this afternoon. Transport winds: NE 10-15 mph this morning; NE 15-18 mph this afternoon. Mixing height: Rises to 3000 feet by 2 p.m. and to near 4000 feet by 5 p.m. Salem's sunset tonight: 7:47 p.m. THREE-HOURLY DATA: 11 a.m. 2 p.m. 5 p.m. 8 p.m. Temperature: 67 75 80 73 Relative Humidity: 49% 39% 32% 41% Surface Wind Direction: 360 010 010 010 Surface Wind Speed: 6 10 12 8 Transport Wind Direction: 030 020 020 020 Transport Wind Speed: 12 15 17 15 Mixing Height: 2500 3000 4000 1500 Ventilation Index: 30 45 68 23 EXTENDED DISCUSSION: An upper-level ridge is forecast to build over Oregon Saturday. At the surface, a thermal trough will build northward along the coast. Transport winds will turn strongly offshore, which will warm valley temperatures to near 90 degrees. Smoke from wildfires, east of the Cascades, may get transported over western Oregon, so don't be surprised if skies become hazy. As the upper-level ridge slides east of the state, increasing southerly flow aloft may bring isolated thunderstorms to the Cascades by late Sunday. Transport winds are forecast to turn weakly onshore in the afternoon, which may help to clear potential wildfire smoke from the region. Further warming aloft should boost valley temperatures into the low 90s. Weak onshore flow may bring minor cooling Monday and Tuesday, but the overall weather pattern forecast for next week is not very favorable for open burning. A broad ridge of high pressure will likely rebuild over the Pacific Northwest. Expect a continuation of dry and quite warm conditions. If the ridge sets up far enough to the east, then afternoon sea breezes could provide limited burning opportunities. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text 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: -------------- next part -------------- A non-text attachment was scrubbed... Name: Silverton Hills AM Forecast.doc Type: application/msword Size: 33280 bytes Desc: Silverton Hills AM Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Fri Sep 2 11:56:46 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 2 Sep 2011 11:56:46 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 11:55 AM PDT FRI SEP 2, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: Northwesterly flow aloft was driving a dry cold front across southeastern Washington late this morning. Weak low-level onshore flow brought marine low clouds onto western Washington and the northwestern corner of Oregon this morning. Skies remained clear across the remainder of the state. Late-morning satellite imagery showed some residual marine clouds over extreme northwestern Oregon, along and near the Columbia River. Skies were clear over the remainder of the state, with the exception of areas of wildfire smoke east of the Cascades. The surface map this morning shows high pressure building into western Washington with a weak trough extending from eastern Washington into northeastern Oregon. Northerly pressure-gradients were increasing across western Oregon, in response to a thermal trough building into southwestern Oregon. The ODF Sodar, located in the central coastal range, was showing NE winds from the surface up to 3000 feet. What's left of the patchy morning low clouds should quickly give way to sunshine this afternoon, as an upper-level ridge of high pressure builds onshore. Transport winds are forecast to remain northeasterly and increase this afternoon. Slightly warmer air aloft will keep maximum mixing heights at or below 4000 feet, with high temperatures climbing into the low 80s. TODAY'S FORECAST: Sunny with near-normal temperatures. Increasing northerly winds. Salem's high temperature today will be near 81 degrees (normal is 80). Relative humidity drops to near 30% by 5 p.m. Surface winds: NNE 10-15 mph this afternoon. Transport winds: NE 14-18 mph this afternoon. Mixing height: Rises to near 3000 feet at 2 p.m. and to 4000 feet by 5 p.m. Salem's sunset tonight: 7:47 p.m. THREE-HOURLY DATA: 2 p.m. 5 p.m. 8 p.m. Temperature: 75 80 73 Relative Humidity: 39% 32% 41% Surface Wind Direction: 005 010 015 Surface Wind Speed: 10 12 8 Transport Wind Direction: 030 030 030 Transport Wind Speed: 15 17 15 Mixing Height: 3000 4000 1500 Ventilation Index: 45 68 23 EXTENDED DISCUSSION: An upper-level ridge is forecast to build over Oregon Saturday. At the surface, a thermal trough will build northward along the coast. Transport winds will turn strongly offshore, which will warm valley temperatures to near 90 degrees. Some smoke, from wildfires east of the Cascades, will likely get transported over western Oregon, so skies should turn hazy. As the upper-level ridge slides east of the state, increasing southerly flow aloft may bring isolated thunderstorms to the Cascades by late Sunday. Transport winds are forecast to turn weakly onshore in the afternoon, which may help to clear any wildfire smoke from the region. Further warming aloft should boost valley temperatures into the low 90s. Weak onshore flow may bring minor cooling Monday and Tuesday, but the overall weather pattern forecast for next week is not very favorable for open burning. A broad ridge of high pressure will likely rebuild over the Pacific Northwest. Expect a continuation of dry and quite warm conditions. Transport winds are forecast to turn back offshore next Wednesday through Friday, which could, once again, transport wildfire smoke into the region. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text 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: -------------- next part -------------- A non-text attachment was scrubbed... Name: Silverton Hills Midday Forecast.doc Type: application/msword Size: 32768 bytes Desc: Silverton Hills Midday Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Tue Sep 6 08:36:18 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 06 Sep 2011 10:36:18 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Tue, Sep 06 2011 Message-ID: An HTML attachment was scrubbed... URL: -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Tue Sep 6 11:50:42 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 06 Sep 2011 13:50:42 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Tue, Sep 06 2011 Message-ID: An HTML attachment was scrubbed... URL: -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Wed Sep 7 08:43:43 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 07 Sep 2011 10:43:43 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Wed, Sep 07 2011 Message-ID: An HTML attachment was scrubbed... URL: -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Wed Sep 7 11:45:00 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 07 Sep 2011 13:45:00 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Wed, Sep 07 2011 Message-ID: An HTML attachment was scrubbed... URL: -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Thu Sep 8 08:57:43 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 8 Sep 2011 08:57:43 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 8:55 AM PDT THU SEP 8, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: A strong and broad upper-level ridge continues to encompass most of the western half of the country this morning. A very weak weather disturbance slid across northern California and southern Oregon overnight. That provided enough mid-level instability to trigger a few high-based thunderstorms over the southern Cascades and south-central Oregon, with very little rainfall. Satellite imagery showed considerable debris clouds are over north-central Oregon this morning, with a few showers possibly developing near The Dalles. Low clouds are banked up along the northern and central coast with scattered mid-level clouds over the interior of western Oregon. Skies remain somewhat smoky, from area wildfires, over western Oregon, with elevated nephelometer readings, especially at Lyons. The Salem sounding this morning showed continued slight warming aloft of the air mass and light north to northeast winds below 5000 feet. At the surface, a thermal trough extends from near The Dalles, through the Willamette Valley, to the southern Oregon coast. Pressure gradients are onshore from Newport to Salem and offshore from Redmond to Salem. The air mass is unseasonably warm between 2500 feet and 6500 feet, so high temperatures will be able to climb well into the 90s again today across the Willamette Valley. The lower atmosphere is quite stable, and mixing heights will not likely even reach 3000 feet this afternoon A few more clouds and higher humidity levels should cap high temperatures at about where they were yesterday. A weak upper-level disturbance is forecast to slowly move into central Oregon today, so afternoon thunderstorm development will likely be confined from the Cascades eastward. However, an evening thunderstorm can't be ruled-out, especially near the Cascade foothills. TODAY'S FORECAST: Partly cloudy and continued very warm. Slight chance of an evening thunderstorm, mainly near the Cascades. Salem's high temperature today will be near 93 degrees (normal is 79). Relative humidity drops to 50% by 11 a.m. and to near 30% by 5 p.m. Surface winds: Light this morning; NNW 5 mph this afternoon. Transport winds: Light this morning; N 10 mph this afternoon. Mixing height: Only rises to about 2800 feet by 5 p.m. Salem's sunset tonight: 7:36 p.m. THREE-HOURLY DATA: 11 a.m. 2 p.m. 5 p.m. 8 p.m. Temperature: 75 85 92 79 Relative Humidity: 50% 36% 29% 46% Surface Wind Direction: Var 350 350 350 Surface Wind Speed: 3 5 5 6 Transport Wind Direction: Var 350 360 360 Transport Wind Speed: 3 10 10 12 Mixing Height: 1200 2000 2800 1000 Ventilation Index: 4 20 28 12 EXTENDED DISCUSSION: The strong upper-level ridge is forecast to remain over the Pacific Northwest through this weekend. The flow aloft will turn north-northeasterly, which should decrease the thunderstorm threat. High temperatures will likely remain in the low to mid 90s. North-northeasterly transport winds will continue to circulate smoke, from area wildfires, over the region. A major change to the weather pattern is in store next week, which will likely bring more favorable burning conditions. The strong upper-level ridge is forecast to finally weaken and shift east of the region about next Tuesday. That will force the surface thermal trough into eastern Oregon and initiate a "Marine Push" into western Oregon. The timing of this transition to onshore flow could create a significant burning opportunity. A weak cold front may also create a burning opportunity around mid-week. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text 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: -------------- next part -------------- A non-text attachment was scrubbed... Name: Silverton Hills AM Forecast.doc Type: application/msword Size: 33280 bytes Desc: Silverton Hills AM Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Thu Sep 8 11:57:01 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 8 Sep 2011 11:57:01 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 11:55 AM PDT THU SEP 8, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: A strong and broad upper-level ridge continues to encompass most of the western half of the country this morning. A very weak weather disturbance is producing a wide band of mainly mid-level clouds that extends from northwestern to southeastern Oregon. Doppler radar is showing what could be some sprinkles near The Dalles. Late-morning satellite imagery also shows low clouds banked up along the northern and central coast. Skies were generally clear south of northern Linn County across western Oregon. Area nephelometer readings are still elevated due to wildfire smoke, especially at Lyons and Government Camp. At the surface, a thermal trough extends from near The Dalles to the southern Oregon coast. It appears anchored over the central Cascades, because pressure gradients continue to be onshore from Newport to Salem and offshore from Redmond to Salem. With unseasonably warm air aloft, between 2500 feet and 6500 feet, high temperatures will be able to climb well into the low 90s again today across the Willamette Valley. The lower atmosphere is quite stable, so mixing heights will likely remain below 3000 feet this afternoon. However, mid-level instability will combine with daytime heating to trigger high-based (dry) thunderstorms over the Cascades. It is possible that some storms could drift over the Willamette Valley, due to light and variable winds aloft. Transport winds should be light today with poor mixing. A pibal is scheduled for 2 p.m. Transport winds are forecast to increase, from the north-northeast, late today and tonight but become variable near thunderstorms. TODAY'S FORECAST: Partly cloudy and continued very warm. Slight chance of an evening thunderstorm, mainly near the Cascades. Salem's high temperature today will be near 93 degrees (normal is 79). Relative humidity drops to near 30% by 5 p.m. Surface winds: Light and variable; becoming NNW 3-8 mph this afternoon. Transport winds: Light and variable; becoming N 6-10 mph this afternoon. Mixing height: Only rises to about 2800 feet by 5 p.m. Salem's sunset tonight: 7:36 p.m. THREE-HOURLY DATA: 2 p.m. 5 p.m. 8 p.m. Temperature: 85 92 79 Relative Humidity: 36% 29% 46% Surface Wind Direction: Var 350 350 Surface Wind Speed: 3 5 4 Transport Wind Direction: Var 360 360 Transport Wind Speed: 4 8 10 Mixing Height: 2000 2800 1000 Ventilation Index: 8 22 10 EXTENDED DISCUSSION: The strong upper-level ridge is forecast to remain over the Pacific Northwest through this weekend. The flow aloft, and at transport level, will turn north-northeasterly on Friday. That will end the thunderstorm threat. High temperatures will remain in the low to mid 90s. North-northeasterly winds will likely circulate more wildfire smoke into the region. A major change to the weather pattern is in store next week, which should finally bring favorable burning conditions. The strong upper-level ridge is forecast to weaken and shift east of the region by next Tuesday. That will force the surface thermal trough into eastern Oregon and initiate a "Marine Push" into western Oregon. The timing of this transition to onshore flow could create a significant burning opportunity Tuesday afternoon. A weak cold front is forecast to approach the coastline by late Wednesday; possibly creating another burning opportunity Wednesday afternoon. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text 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: -------------- next part -------------- A non-text attachment was scrubbed... Name: Silverton Hills Midday Forecast.doc Type: application/msword Size: 33280 bytes Desc: Silverton Hills Midday Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Fri Sep 9 08:59:17 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 9 Sep 2011 08:59:17 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 8:55 AM PDT FRI SEP 9, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: A strong and broad upper-level ridge of high pressure is in the process of rebuilding over Oregon, in the wake of a weak weather disturbance that brought some dry thunderstorms to areas mainly east of the Cascades the past two days. Northerly flow aloft has stabilized the air mass over the state. At the surface, a thermal trough extends from southeastern Washington to the northern Oregon Cascades, with a new thermal trough building northward along the southern Oregon Coast. Pressure gradients are still weakly onshore along the northern and central Oregon Coast but becoming mostly northerly. The flow has turned offshore along the south coast. Pressure gradients are weak across the Willamette Valley this morning with light winds. Mid-morning satellite imagery showed low clouds along the northern and central coast but not much penetration inland into the coastal mountain gaps. Skies were clear over the south coast and the inland valleys of western Oregon. Some debris clouds from yesterday evening's convective activity were still evident over central Oregon. Nephelometer readings have dropped slightly, from yesterday morning, but are still elevated across most of the state, due to wildfire smoke. The Salem sounding this morning was almost identical to yesterday morning with unseasonably warm from about 2500 feet to 6500 feet. That will keep mixing heights suppressed below 3000 feet today, even though surface temperatures will warm into the low 90s. North-northeasterly transport winds will increase this afternoon, across the Willamette Valley, into the building surface thermal trough along the south coast. TODAY'S FORECAST: Sunny and very warm. Salem's high temperature today will be near 92 degrees (normal is 79). Relative humidity drops below 50% by 11 a.m. and to near 25% by 5 p.m. Surface winds: N 3-8 mph this morning; N 7-12 mph this afternoon. Transport winds: NNE 10 mph this morning; NNE 15 mph this afternoon. Mixing height: Rises to only about 2900 feet by 5 p.m. Salem's sunset tonight: 7:34 p.m. THREE-HOURLY DATA: 11 a.m. 2 p.m. 5 p.m. 8 p.m. Temperature: 74 85 91 80 Relative Humidity: 45% 31% 26% 37% Surface Wind Direction: 360 010 010 010 Surface Wind Speed: 5 8 10 7 Transport Wind Direction: 010 010 010 020 Transport Wind Speed: 10 15 17 12 Mixing Height: 1500 2700 2900 1500 Ventilation Index: 15 41 49 18 EXTENDED DISCUSSION: The strong upper-level ridge is forecast to remain over the Pacific Northwest through this weekend. Sunny skies and very warm air aloft will push high temperatures into the mid 90s. North-northeasterly flow on Saturday will likely circulate more wildfire smoke into the region. Transport winds will slacken on Sunday, as the surface thermal trough moves over the valley. A major change to the weather pattern is in store next week, which should finally clear the wildfire smoke from the region and bring favorable burning conditions. The strong upper-level ridge is forecast to slowly shift eastward and weaken. That will push the surface thermal trough east of the Cascades by Monday afternoon and initiate a cooling onshore flow pattern into western Oregon. By Tuesday, the thermal trough is forecast to move into eastern Oregon with strengthening onshore flow likely creating favorable burning conditions. Increasing westerly flow aloft will maintain onshore flow through the week. A weak cold front is forecast to approach the coastline by Thursday, which may also create favorable burning conditions. This system may also be strong enough to bring some light showers to the region, but that is questionable at this time. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text 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: -------------- next part -------------- A non-text attachment was scrubbed... Name: Silverton Hills AM Forecast.doc Type: application/msword Size: 33280 bytes Desc: Silverton Hills AM Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Fri Sep 9 11:59:05 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 9 Sep 2011 11:59:05 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 11:55 AM PDT FRI SEP 9, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: A strong and broad upper-level ridge of high pressure is in the process of rebuilding over the Pacific Northwest. The ridge axis is just offshore, so the flow aloft has turned north-northeasterly over Oregon. That is a stable flow pattern, so thunderstorm development is unlikely across the state today. The late-morning ODF surface analysis showed a thermal trough extending from southeastern Washington to the northern Oregon Cascades, with a new thermal trough building northward along the southern Oregon Coast. Pressure gradients are still weakly onshore along the northern and central Oregon coast but becoming mostly northerly. The flow is offshore along the south coast. Pressure gradients are weakly northerly across the Willamette Valley. Late-morning satellite imagery showed low clouds along the northern and central coast had backed off to just the immediate coastal strip. Skies were clear over the south coast and over the interior western Oregon. Smoke from local wildfires has spread out to cover most of the state, so nephelometer readings are still elevated. Conditions are highly unfavorable for burning today. Very warm air aloft will keep mixing heights suppressed below 3000 feet today, even though surface temperatures will warm into the low 90s. North-northeasterly transport winds will increase this afternoon. Much of the valley will approach State Fire Marshal Burn Ban conditions by late this afternoon, due to the combination of warm temperatures, low humidity and increasing northerly winds. TODAY'S FORECAST: Sunny and very warm. Salem's high temperature today will be near 92 degrees (normal is 79). Relative humidity drops to near 25% by 5 p.m. Surface winds: North increasing to 7-15 mph this afternoon. Transport winds: NNE 15 mph this afternoon. Mixing height: Rises to only about 2900 feet by 5 p.m. Salem's sunset tonight: 7:34 p.m. THREE-HOURLY DATA: 2 p.m. 5 p.m. 8 p.m. Temperature: 85 91 80 Relative Humidity: 31% 26% 37% Surface Wind Direction: 010 010 010 Surface Wind Speed: 8 10 7 Transport Wind Direction: 010 010 020 Transport Wind Speed: 15 17 12 Mixing Height: 2700 2900 1500 Ventilation Index: 41 49 18 EXTENDED DISCUSSION: The strong upper-level ridge is forecast to remain over the Pacific Northwest through this weekend. The air aloft will be warm enough to support 100-degree temperatures, but smoky skies and the lowering September sun-angle will likely combine to hold highs in the mid 90s. North-northeasterly flow on Saturday will likely circulate more wildfire smoke into the region. Transport winds will slacken on Sunday, as the surface thermal trough moves over the valley. The thermal trough may shift eastward, to over the Cascades, Sunday afternoon, with transport winds turning weakly onshore. A major change to the weather pattern is in store next week, which should finally clear the wildfire smoke from the region and bring favorable burning conditions. The strong upper-level ridge is forecast to slowly shift eastward and weaken. That will push the surface thermal trough east of the Cascades by Monday afternoon and initiate a cooling onshore flow pattern into western Oregon. Mixing heights will likely remain low (probably no higher than 3000 feet), which would limit any burning opportunity. By Tuesday, the thermal trough is forecast to move into eastern Oregon. Strengthening onshore flow and slightly higher mixing heights will likely creating more favorable burning conditions. Weak westerly flow aloft is forecast for the remainder of next week. Transport winds may become northerly on Wednesday but are forecast to turn back onshore Thursday, ahead of an approaching weak cold front. That may create another favorable burning opportunity. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text 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: -------------- next part -------------- A non-text attachment was scrubbed... Name: Silverton Hills Midday Forecast.doc Type: application/msword Size: 33280 bytes Desc: Silverton Hills Midday Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Mon Sep 12 08:39:35 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 12 Sep 2011 10:39:35 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Mon, Sep 12 2011 Message-ID: An HTML attachment was scrubbed... URL: -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Mon Sep 12 11:55:41 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 12 Sep 2011 13:55:41 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Mon, Sep 12 2011 Message-ID: An HTML attachment was scrubbed... URL: -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Tue Sep 13 08:46:34 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 13 Sep 2011 10:46:34 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Tue, Sep 13 2011 Message-ID: An HTML attachment was scrubbed... URL: -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Wed Sep 14 08:25:56 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 14 Sep 2011 10:25:56 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Wed, Sep 14 2011 Message-ID: An HTML attachment was scrubbed... URL: -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Tue Sep 13 08:58:27 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 13 Sep 2011 10:58:27 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Tue, Sep 13 2011 Message-ID: An HTML attachment was scrubbed... URL: -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Wed Sep 14 11:55:54 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 14 Sep 2011 13:55:54 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Wed, Sep 14 2011 Message-ID: An HTML attachment was scrubbed... URL: -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Thu Sep 15 08:30:16 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 15 Sep 2011 10:30:16 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Thu, Sep 15 2011 Message-ID: An HTML attachment was scrubbed... URL: -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Thu Sep 15 08:31:53 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 15 Sep 2011 10:31:53 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Thu, Sep 15 2011 Message-ID: An HTML attachment was scrubbed... URL: -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Fri Sep 16 08:50:09 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 16 Sep 2011 08:50:09 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 8:45 AM PDT FRI SEP 16, 2011 BURN ADVISORY: Recommended burn times for agricultural burning are from 8:00am to 5:30pm. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: Upper level trough will move through the region today keeping the air mass cool and cloudy. Morning satellite picture shows a mass of clouds moving through the westerly flow aloft. These may produce some sprinkles or light showers but little more. It appears the main bulk of these clouds will move through this afternoon to early evening with some clearing later today. Upper level sounding shows a stable layer up to 2000 ft with mostly unstable and very moist conditions above that. With slow heating this layer will mix out and provide good to excellent mixing by early afternoon. Morning surface map shows weak high pressure over the region with little pressure gradient. Current gradient stacking shows .4 mb onshore from Newport to Salem with 0 mb between Salem to Redmond. It does not appear gradients will increase much today and will keep winds generally light but mostly W to NW. This factor may limit open burning today. TODAY'S FORECAST: Mostly cloudy and cool. Salem's high temperature today will be near 68 degrees. Relative humidity drops below 50% by 2 p.m. and to near 40% by 5 p.m. Surface winds: Light and variable this morning; W to NW at 4-7 mph this afternoon. Transport winds: Light and variable this morning; W to NW at 5-8 mph this afternoon. Mixing height: Brief morning stability, then mixing height rising to 5000 ft by 1 p.m. Salem's sunset tonight: 7:34 p.m. THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 60 66 68 60 Relative Humidity: 69% 49% 40% 55% Surface Wind Direction: 360 290 300 280 Surface Wind Speed: 2 4 7 6 Transport Wind Direction: 350 300 290 290 Transport Wind Speed: 2 6 7 7 Estimated Mixing Height: 3500 5000 5000+ 2500 Ventilation Index: 7 30 35 18 EXTENDED DISCUSSION: Very minor upper level ridge moves into the region tomorrow behind the exit of today's trough. This feature will be short-lived as the next trough and minor front move into the region Sunday. However, each succeeding run of the models show this front weakening with now only a chance of light showers in the northern Willamette Valley. Weak trough moves through Monday then an upper level ridge builds in later Monday and Tuesday. The ridge will move on to the east later Tuesday and Wednesday. Models continue to show mostly SW'erly flow through much of the extended period which should provide continued opportunities to burn even if they're somewhat limited. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text 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 ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: Silverton Hills Midday Forecast.doc Type: application/msword Size: 31232 bytes Desc: Silverton Hills Midday Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Fri Sep 16 11:46:58 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 16 Sep 2011 11:46:58 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 11:45 AM PDT FRI SEP 16, 2011 BURN ADVISORY: Recommended burn times for agricultural burning are from 8:00am to 5:30pm. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: Upper level trough is moving through the region today. The satellite pictures are showing the mass of clouds associated with the trough are breaking up as they continue to move eastward. Expect skies to clear to partly cloudy this afternoon. With clearing skies mixing heights will quickly lift above 5000 ft. Hopefully the clearing will increase gradient stacking more over the Coast Range than the Cascades. Currently gradient stacking favors the Cascades with .3 mb onshore from Newport to Salem and 1.0 mb onshore from Salem to Redmond. TODAY'S FORECAST: Mostly cloudy becoming partly cloudy this afternoon. Salem's high temperature today will be near 69 degrees. Relative humidity drops below 50% by 2 p.m. and to near 40% by 5 p.m. Surface winds: Light and variable this morning; W to NW at 4-7 mph this afternoon. Transport winds: Light and variable this morning; W to NW at 5-9 mph this afternoon. Mixing height: Brief morning stability, then mixing height rising to 5000 ft by 1 p.m. Salem's sunset tonight: 7:34 p.m. THREE-HOURLY DATA: 2pm 5pm 8pm Temperature: 66 69 60 Relative Humidity: 49% 40% 55% Surface Wind Direction: 290 300 280 Surface Wind Speed: 4 7 6 Transport Wind Direction: 300 290 290 Transport Wind Speed: 6 7 7 Estimated Mixing Height: 5000 5000+ 2500 Ventilation Index: 30 35 18 EXTENDED DISCUSSION: Very minor upper level ridge moves into the region tomorrow behind the exit of today's trough. This feature will be short-lived as the next trough and minor front move into the region Sunday. However, each succeeding run of the models show this front weakening with now only a chance of light showers in the northern Willamette Valley. Wind flow continues to look favorable for burning both Saturday and Sunday with light SSW to WSW flow. Gradient stacking will be questionable however. Weak trough moves through Monday then an upper level ridge builds in later Monday and Tuesday. The ridge will move on to the east later Tuesday and Wednesday. Models continue to show mostly SW'erly flow through much of the extended period which should provide continued opportunities to burn even if they're somewhat limited. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text 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 ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: Silverton Hills Midday Forecast.doc Type: application/msword Size: 31744 bytes Desc: Silverton Hills Midday Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Mon Sep 19 08:18:12 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 19 Sep 2011 10:18:12 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Mon, Sep 19 2011 Message-ID: An HTML attachment was scrubbed... URL: -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Mon Sep 19 08:25:10 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 19 Sep 2011 10:25:10 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Mon, Sep 19 2011 Message-ID: An HTML attachment was scrubbed... URL: -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Mon Sep 19 11:39:46 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 19 Sep 2011 13:39:46 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Mon, Sep 19 2011 Message-ID: An HTML attachment was scrubbed... URL: -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Tue Sep 20 08:38:53 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 20 Sep 2011 10:38:53 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Tue, Sep 20 2011 Message-ID: An HTML attachment was scrubbed... URL: -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Wed Sep 21 08:56:44 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 21 Sep 2011 08:56:44 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 8:55 AM PDT WED SEP 21, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: A strong and broad upper-level ridge of high pressure remains anchored over the Rockies with light southwesterly winds aloft over Oregon. At the surface, pressure gradients are offshore across western Oregon with light easterly winds coming down the Columbia Gorge. Winds are light in the Willamette Valley, but the Salem sounding, from early this morning, showed light easterly winds from just above the surface up to about 2000 feet. Satellite imagery shows an impressive-looking frontal system extending from the southern British Columbia coast to about 400 miles west of the northern Oregon coast. Some mid-level clouds from this system were streaming across the northwestern corner of Oregon, but skies remained clear over the remainder of the state. The latest computer guidance is forecasting very little eastward progress of the offshore weather system today. There may be some increase in mid-level clouds, but warm air aloft will suppress mixing heights. Valley temperatures are running 5-9 degrees warmer than 24 hours ago, so afternoon highs should climb into the upper 80s. Due to the advancing cold front, transport winds are forecast to slacken by mid-afternoon; possibly turning weakly onshore in the late-afternoon. Mixing heights will struggle to reach 3000 feet today. Transport winds will need to be monitored closely for the possibility of a limited burning opportunity. TODAY'S FORECAST: Partly cloudy and warmer. Salem's high temperature today will be near 87 degrees (normal is 76). Relative humidity drops below 50% by noon and to near 30% by 5 p.m. Surface winds: Light SE this morning; becoming light SW late this afternoon. Transport winds: Light SE this morning; turning light SW late this afternoon. Mixing height: Below 2000 feet this morning; rising to 3000 feet by 5 p.m. Salem's sunset tonight: 7:12 p.m. THREE-HOURLY DATA: 11 a.m. 2 p.m. 5 p.m. 8 p.m. Temperature: 69 81 85 71 Relative Humidity: 53% 35% 31% 49% Surface Wind Direction: 150 Var 250 250 Surface Wind Speed: 3 3 4 4 Transport Wind Direction: 150 Var 250 250 Transport Wind Speed: 3 3 4 7 Mixing Height: 1300 2500 3200 1200 Ventilation Index: 4 8 13 8 EXTENDED DISCUSSION: The strong Rocky Mountain ridge is forecast to weaken slightly Thursday and Friday with increasing southwesterly flow aloft over Oregon. The surface thermal trough should push well east of the Cascades with slight cooling aloft and southwesterly transport winds likely creating favorable afternoon burning conditions both days. The flow aloft, and at transport level, is forecast to become more southerly, on Saturday, as an upper-level trough digs offshore. Some computer models are showing rain-making weather systems moving onshore Sunday through Tuesday of next week. Longer-range charts are indicating a return of dry weather beginning about next Wednesday. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text 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: -------------- next part -------------- A non-text attachment was scrubbed... Name: Silverton Hills AM Forecast.doc Type: application/msword Size: 32768 bytes Desc: Silverton Hills AM Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Wed Sep 21 11:56:22 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 21 Sep 2011 11:56:22 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 11:55 AM PDT WED SEP 21, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: A strong and broad upper-level ridge of high pressure remains anchored over the Rockies with light southwesterly winds aloft over Oregon. At the surface, pressure gradients were still offshore as of late this morning across western Oregon with light easterly winds continuing to funnel through the Columbia Gorge into the northern Willamette Valley. Winds are light southeasterly in the central and southern Willamette Valley. Satellite imagery shows a cold front extending from the northern tip of Vancouver Island, British Columbia to about 350 miles west of the northern Oregon coast. Some mid-level clouds from this system have spread as far south and east as the northwestern corner of Oregon. Skies are sunny across the remainder of the state, including most of the coastline, due to the offshore low-level winds. Very slow eastward progress of the offshore weather system is forecast for this afternoon. Warm air aloft will keep mixing heights suppressed. Valley temperatures are running about 5-9 degrees warmer than 24 hours ago, so afternoon highs should climb into the upper 80s. Offshore transport winds are forecast to slacken by mid-afternoon and could possibly turn weakly onshore by late-afternoon. Pibals are scheduled to begin at 1 p.m. Due to the very warm air aloft, mixing heights will struggle to reach 3000 feet today. That will limit burning opportunities, even if transport winds eventually turn weakly onshore later this afternoon. TODAY'S FORECAST: Partly cloudy and warmer. Salem's high temperature today will be near 87 degrees (normal is 76). Relative humidity drops to near 30% by 5 p.m. Surface winds: Light SE; becoming light S later this afternoon. Transport winds: Light SE; possibly turning light SW later this afternoon. Mixing height: Slowly rising to 3000 feet by 5 p.m. Salem's sunset tonight: 7:12 p.m. THREE-HOURLY DATA: 2 p.m. 5 p.m. 8 p.m. Temperature: 81 85 71 Relative Humidity: 35% 31% 49% Surface Wind Direction: 160 180 210 Surface Wind Speed: 4 3 4 Transport Wind Direction: Var 230 230 Transport Wind Speed: 4 5 5 Mixing Height: 2500 3200 1200 Ventilation Index: 10 16 6 EXTENDED DISCUSSION: The strong Rocky Mountain ridge is forecast to weaken slightly Thursday and Friday with increasing southwesterly flow aloft over Oregon. The surface thermal trough should push well east of the Cascades with slight cooling aloft and southwesterly transport winds likely creating favorable afternoon burning conditions both days. The flow aloft, and at transport level, is forecast to become more southerly, on Saturday, as an upper-level trough digs offshore. Computer models are showing rain-making weather systems moving onshore Sunday through Tuesday of next week with a break from the rain next Wednesday and Thursday. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text 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: -------------- next part -------------- A non-text attachment was scrubbed... Name: Silverton Hills Midday Forecast.doc Type: application/msword Size: 32768 bytes Desc: Silverton Hills Midday Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Thu Sep 22 08:56:24 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 22 Sep 2011 08:56:24 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 8:55 AM PDT THU SEP 22, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is allowed from 2:00 p.m. until 5:00 p.m. WEATHER DISCUSSION: A persistent upper-level ridge of high pressure, centered over the Rockies, is beginning to weaken with increasing southwesterly flow aloft over Oregon Satellite imagery shows a broad band of clouds extending from southern British Columbia across western Washington and northwestern Oregon. Low clouds have also moved onshore along the entire length of the Oregon coast. Radar and surface observations show areas of light rain across much of western Washington, but Oregon has remained dry. Skies are still mostly sunny from the Cascades eastward and over the interior of southwestern Oregon. The Salem sounding this morning had a very similar temperature profile to 24 hours ago. The biggest difference was an increase in southwesterly winds aloft. At the surface, pressure-gradients are still weakly offshore across western Oregon with gradients turning southerly across the Willamette Valley. The frontal system to our north and west is forecast to stall and weaken today. Some clouds will continue to stream across the Willamette Valley, but rain should spread no further south than the northern Oregon coast. The air mass aloft is still very warm, which will suppress afternoon mixing again today. Valley temperatures should be about 5 degrees cooler today due to more clouds and weak onshore flow expected this afternoon. South-southwesterly transport winds are forecast for this afternoon, which could produce favorable burning conditions, if pressure-gradients turn strongly enough onshore. TODAY'S FORECAST: Partly cloudy and warm. Salem's high temperature today will be near 83 degrees (normal is 75). Relative humidity drops below 50% by 11 a.m. and to near 35% by 5 p.m. Surface winds: S 3-6 mph this morning; becoming SSW 4-8 mph this afternoon. Transport winds: SSW 10 mph this morning; SW 10-15 mph this afternoon. Mixing height: Rising to 3000 feet by 2 p.m. and to near 4000 feet by 5 p.m. Salem's sunset tonight: 7:10 p.m. THREE-HOURLY DATA: 11 a.m. 2 p.m. 5 p.m. 8 p.m. Temperature: 69 78 82 70 Relative Humidity: 47% 41% 36% 55% Surface Wind Direction: 180 200 200 230 Surface Wind Speed: 4 5 5 4 Transport Wind Direction: 200 220 220 230 Transport Wind Speed: 10 12 14 10 Mixing Height: 1700 3000 4000 1000 Ventilation Index: 17 36 56 10 EXTENDED DISCUSSION: Little change in the weather pattern is forecast for Friday, so another afternoon burning opportunity is possible. The flow aloft, and at transport level, is forecast to become more southerly, on Saturday, as an upper-level trough digs offshore. Computer models are showing rain-making weather systems moving onshore Sunday through Tuesday of next week with a possible break from the rain next Wednesday and Thursday. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text 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: -------------- next part -------------- A non-text attachment was scrubbed... Name: Silverton Hills AM Forecast.doc Type: application/msword Size: 32768 bytes Desc: Silverton Hills AM Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Thu Sep 22 11:57:12 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 22 Sep 2011 11:57:12 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 11:55 AM PDT THU SEP 22, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is allowed from 2:00 p.m. until 5:00 p.m. WEATHER DISCUSSION: A persistent upper-level ridge of high pressure, centered over the Rockies, is beginning to weaken with increasing southwesterly flow aloft over Oregon Midday satellite imagery shows a broad band of clouds extending from southern British Columbia across most of Washington and northwestern Oregon. Radar and surface observations show that the areas of light rain have decreased across western Washington. Some light rain was still falling along the Washington coast, and a trace of rain fell as far south as Astoria. The Salem sounding this morning still showed a very warm air mass aloft, so mixing heights will be slow to rise this afternoon. At the surface, a weak thermal trough remains over western Oregon with light southeasterly pressure-gradients across the Willamette Valley. The offshore frontal system is weakening but will continue to spread considerable clouds over western Oregon today. Temperatures should be about 5 degrees cooler, with low-level winds forecast to turn weakly onshore this afternoon. That could create a burning opportunity, if the flow turns enough westerly to keep smoke out of the northern Willamette Valley. Pibals are scheduled to begin at noon. TODAY'S FORECAST: Partly cloudy and warm. Salem's high temperature today will be near 83 degrees (normal is 75). Relative humidity drops below 50% by 11 a.m. and to near 35% by 5 p.m. Surface winds: SE 4-7 mph; becoming SSW 4-8 mph this afternoon. Transport winds: SSW 10-15 mph this afternoon. Mixing height: Rising to 3000 feet by 2 p.m. and to near 3500 feet by 5 p.m. Salem's sunset tonight: 7:10 p.m. THREE-HOURLY DATA: 2 p.m. 5 p.m. 8 p.m. Temperature: 78 82 70 Relative Humidity: 41% 36% 55% Surface Wind Direction: 200 200 230 Surface Wind Speed: 5 5 4 Transport Wind Direction: 220 220 230 Transport Wind Speed: 12 14 10 Mixing Height: 3000 3500 1000 Ventilation Index: 36 49 10 EXTENDED DISCUSSION: A very similar day is forecast for Friday, with the potential for an afternoon burning opportunity if the transport winds can take on enough of a westerly component. The flow will become more southerly, on Saturday, as an upper-level trough digs offshore. Computer models are showing rain-making weather systems moving onshore Sunday through Tuesday of next week with a possible break from the rain next Wednesday and Thursday. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text 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: -------------- next part -------------- A non-text attachment was scrubbed... Name: Silverton Hills Midday Forecast.doc Type: application/msword Size: 32256 bytes Desc: Silverton Hills Midday Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Fri Sep 23 08:56:32 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 23 Sep 2011 08:56:32 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 8:55 AM PDT FRI SEP 23, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is allowed from 1:00 p.m. until 5:00 p.m. WEATHER DISCUSSION: The first day of autumn will bring a continuation of summer-like weather across the state. A persistent upper-level ridge of high pressure remains centered over the Rockies with a warm and dry southwesterly flow aloft over Oregon. The weak frontal system that spread middle and high clouds across northwestern Oregon on Thursday dissipated overnight. Satellite imagery this morning shows a broad band of clouds, associated with a strong southwesterly jet stream, extending from northern Vancouver Island, British Columbia to about 450 miles west of the northern Oregon coast. With the exception of coastal low clouds, skies are mostly sunny across Oregon. The Salem sounding this morning was nearly identical to Thursday morning; showing a very warm air mass and continued southwesterly winds aloft. At the surface, a weak thermal trough remains over southwestern Oregon with light pressure-gradients across the Willamette Valley. The offshore frontal system is forecast to remain nearly stationary today. Sunny skies and warm air aloft will help valley temperatures climb to a few degrees warmer than on Thursday and to more than 10 degrees above normal. Like yesterday, south-southwesterly transport winds could create favorable afternoon burning conditions. TODAY'S FORECAST: Sunny and unseasonably warm. Salem's high temperature today will be near 86 degrees (normal is 75). Relative humidity drops below 50% by 1 p.m. and to near 40% by 5 p.m. Surface winds: S 3-6 mph this morning; becoming SSW 4-8 mph this afternoon. Transport winds: SSW 10 mph this morning; SW 10-15 mph this afternoon. Mixing height: Rising to 3000 feet by 1 p.m. and to near 4000 feet by 5 p.m. Salem's sunset tonight: 7:08 p.m. THREE-HOURLY DATA: 11 a.m. 2 p.m. 5 p.m. 8 p.m. Temperature: 72 82 85 76 Relative Humidity: 57% 45% 39% 55% Surface Wind Direction: 180 200 200 230 Surface Wind Speed: 4 5 5 4 Transport Wind Direction: 200 220 220 230 Transport Wind Speed: 10 12 12 10 Mixing Height: 1700 3200 4000 1000 Ventilation Index: 17 38 48 10 EXTENDED DISCUSSION: The flow aloft, and at transport level, will become more southerly, on Saturday, as an upper-level trough digs offshore. The southerly flow will act to depress mixing heights. Computer models are showing a slow-moving frontal system finally making it onshore Saturday night with rain likely spreading across the Willamette Valley by midday Sunday. At least one-tenth of an inch of rain is likely Sunday with a stronger front bringing more than one-quarter of an inch of rain on Monday. Long-range models are inconsistent after that time, but drier weather is likely for the middle of next week. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text 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: -------------- next part -------------- A non-text attachment was scrubbed... Name: Silverton Hills AM Forecast.doc Type: application/msword Size: 32768 bytes Desc: Silverton Hills AM Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Fri Sep 23 11:47:22 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 23 Sep 2011 11:47:22 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 8:55 AM PDT FRI SEP 23, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is allowed from 1:00 p.m. until 5:00 p.m. WEATHER DISCUSSION: The first day of autumn will bring a continuation of summer-like weather across the state. A persistent upper-level ridge of high pressure remains centered over the Rockies with a warm and dry southwesterly flow aloft over Oregon. The weak frontal system that spread middle and high clouds across northwestern Oregon on Thursday dissipated overnight. Satellite imagery this morning shows a broad band of clouds, associated with a strong southwesterly jet stream, extending from northern Vancouver Island, British Columbia to about 450 miles west of the northern Oregon coast. With the exception of coastal low clouds, skies are mostly sunny across Oregon. The Salem sounding this morning was nearly identical to Thursday morning; showing a very warm air mass and continued southwesterly winds aloft. At the surface, a weak thermal trough remains over southwestern Oregon with light pressure-gradients across the Willamette Valley. The offshore frontal system is forecast to remain nearly stationary today. Sunny skies and warm air aloft will help valley temperatures climb to a few degrees warmer than on Thursday and to more than 10 degrees above normal. Like yesterday, south-southwesterly transport winds could create favorable afternoon burning conditions. TODAY'S FORECAST: Sunny and unseasonably warm. Salem's high temperature today will be near 86 degrees (normal is 75). Relative humidity drops below 50% by 1 p.m. and to near 40% by 5 p.m. Surface winds: S 3-6 mph this morning; becoming SSW 4-8 mph this afternoon. Transport winds: SSW 10 mph this morning; SW 10-15 mph this afternoon. Mixing height: Rising to 3000 feet by 1 p.m. and to near 4000 feet by 5 p.m. Salem's sunset tonight: 7:08 p.m. THREE-HOURLY DATA: 11 a.m. 2 p.m. 5 p.m. 8 p.m. Temperature: 72 82 85 76 Relative Humidity: 57% 45% 39% 55% Surface Wind Direction: 180 200 200 230 Surface Wind Speed: 4 5 5 4 Transport Wind Direction: 200 220 220 230 Transport Wind Speed: 10 12 12 10 Mixing Height: 1700 3200 4000 1000 Ventilation Index: 17 38 48 10 EXTENDED DISCUSSION: The flow aloft, and at transport level, will become more southerly, on Saturday, as an upper-level trough digs offshore. The southerly flow will act to depress mixing heights. Computer models are showing a slow-moving frontal system finally making it onshore Saturday night with rain likely spreading across the Willamette Valley by midday Sunday. At least one-tenth of an inch of rain is likely Sunday with a stronger front bringing more than one-quarter of an inch of rain on Monday. Long-range models are inconsistent after that time, but drier weather is likely for the middle of next week. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text 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: -------------- next part -------------- A non-text attachment was scrubbed... Name: Silverton Hills Midday Forecast.doc Type: application/msword Size: 32768 bytes Desc: Silverton Hills Midday Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Fri Sep 23 11:48:46 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 23 Sep 2011 11:48:46 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 11:45 AM PDT FRI SEP 23, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is allowed from 1:00 p.m. until 5:00 p.m. WEATHER DISCUSSION: A dry and warm southwesterly flow aloft is bringing sunny and unseasonably warm weather to western Oregon for this first official day of autumn. The only exception is along the immediate coastline, where low clouds have been producing areas of light mist, especially north. The surface chart shows a broad thermal trough extending from central Washington, through the Willamette Valley, into southwestern Oregon. Gradients are weakly onshore from Newport to Salem and weakly offshore from Redmond to Salem, with light winds and sunshine across the Willamette Valley. Satellite imagery shows a broad band of clouds, associated with a strong southwesterly jet stream, extending from northern Vancouver Island, British Columbia to about 450 miles west of the northern Oregon coast. A wave forming along the front will stall its eastward progress today. Sunny skies, warm air aloft, and light surface winds will combine to keep valley temperatures more than 10 degrees above normal today. Warmer surface temperatures, compared to yesterday, should make for slightly higher mixing heights. South-southwesterly transport winds should creating favorable afternoon burning conditions. Pibals are scheduled to begin at noon. TODAY'S FORECAST: Sunny and unseasonably warm. Salem's high temperature today will be near 86 degrees (normal is 75). Relative humidity drops below 50% by 1 p.m. and to near 40% by 5 p.m. Surface winds: SSW 4-8 mph this afternoon. Transport winds: SSW 10-15 mph this afternoon. Mixing height: Rising to 3000 feet by 1 p.m. and to near 4000 feet by 5 p.m. Salem's sunset tonight: 7:08 p.m. THREE-HOURLY DATA: 2 p.m. 5 p.m. 8 p.m. Temperature: 82 85 76 Relative Humidity: 45% 39% 55% Surface Wind Direction: 200 200 230 Surface Wind Speed: 4 5 4 Transport Wind Direction: 220 220 230 Transport Wind Speed: 12 12 10 Mixing Height: 3200 4000 1000 Ventilation Index: 38 48 10 EXTENDED DISCUSSION: The flow will become more southerly, on Saturday, as an upper-level trough digs offshore. Look for increasing high clouds, in the afternoon, with lower mixing heights than today. A slow-moving frontal system will finally come onshore Saturday night with computer models bringing about one-tenth of an inch of rain into the northern Willamette Valley on Sunday. A stronger cold front may spread more significant rainfall across western Oregon Monday afternoon through Tuesday morning. Longer-range models are now more consistent in showing dry weather returning for the second half of next week. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text 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: -------------- next part -------------- A non-text attachment was scrubbed... Name: Silverton Hills Midday Forecast.doc Type: application/msword Size: 32768 bytes Desc: Silverton Hills Midday Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Mon Sep 26 08:13:26 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 26 Sep 2011 10:13:26 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Mon, Sep 26 2011 Message-ID: An HTML attachment was scrubbed... URL: -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Mon Sep 26 11:53:48 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 26 Sep 2011 13:53:48 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Mon, Sep 26 2011 Message-ID: An HTML attachment was scrubbed... URL: -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Tue Sep 27 08:28:50 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 27 Sep 2011 10:28:50 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Tue, Sep 27 2011 Message-ID: An HTML attachment was scrubbed... URL: -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Tue Sep 27 11:31:01 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 27 Sep 2011 13:31:01 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Tue, Sep 27 2011 Message-ID: An HTML attachment was scrubbed... URL: -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Wed Sep 28 11:35:57 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 28 Sep 2011 13:35:57 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Wed, Sep 28 2011 Message-ID: An HTML attachment was scrubbed... URL: -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Thu Sep 29 08:57:31 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 29 Sep 2011 08:57:31 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 8:55 AM PDT THU SEP 29, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is allowed from 2:00 p.m. until 5:00 p.m. WEATHER DISCUSSION: A strong upper-level ridge of high pressure remains centered over the Rockies with a warm and dry southwesterly flow aloft over Oregon. The surface map this morning shows high pressure centered over NE Oregon and a thermal trough centered just off the coast. That is resulting in strong offshore flow across all of western Oregon. Surface winds in the Willamette Valley are light, but easterly winds are gusting to around 30 mph at the western end of the Columbia Gorge. Coastal winds are also light easterly. The Salem sounding this morning showed very warm air aloft with a surface-based temperature inversion extending up to almost 5000 feet. Winds were light and variable near the surface with a layer of offshore flow from about 1000 feet to 3000 feet. Winds shift to the south-southwest above 3000 feet. The upper-level ridge is forecast to slowly shift eastward today with the surface thermal trough moving over the Willamette Valley. That will combine with a full day of sunshine to make for unseasonably warm temperatures. Due to very warm air aloft and a lowering autumn sun-angle, mixing heights will struggle to reach 3000 feet today. As the thermal trough shifts inland this afternoon, offshore transport winds are forecast to weaken and eventually become light south-southwesterly. That will need to be monitored closely, because it could create favorable enough burning conditions to take care of the few remaining fields late today. TODAY'S FORECAST: Sunny and unseasonably warm. Salem's high temperature today will be near 84 degrees (normal is 72). Relative humidity drops below 50% by 11 a.m. and to near 30% by 5 p.m. Surface winds: N-NE 3-6 mph; becoming variable 3-7 mph this afternoon. Transport winds: ENE 3-6 mph this morning; SSW 6-10 mph this afternoon. Mixing height: Rising to 3000 feet by 3 p.m. and to near 3500 feet by 5 p.m. Salem's sunset tonight: 6:57 p.m. THREE-HOURLY DATA: 11 a.m. 2 p.m. 5 p.m. 8 p.m. Temperature: 66 78 83 68 Relative Humidity: 49% 33% 30% 52% Surface Wind Direction: 020 360 Var 230 Surface Wind Speed: 3 5 5 5 Transport Wind Direction: 080 200 220 230 Transport Wind Speed: 3 6 10 7 Mixing Height: 1700 2500 3500 1000 Ventilation Index: 5 15 35 7 EXTENDED DISCUSSION: The upper-level ridge is forecast to weaken and shift further to the east on Friday. Increasing southwesterly flow aloft will force the surface thermal trough into eastern Oregon. Onshore flow will cool temperatures back close to normal with increasing clouds. There could be an opportunity to burn any remaining fields, if appropriate conditions do not set up today. A series of weather systems are forecast to move onshore, beginning Saturday. Stormy weather next week will likely prohibit further burning this season. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text 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: -------------- next part -------------- A non-text attachment was scrubbed... Name: Silverton Hills AM Forecast.doc Type: application/msword Size: 32768 bytes Desc: Silverton Hills AM Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Thu Sep 29 11:57:01 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 29 Sep 2011 11:57:01 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 11:55 AM PDT THU SEP 29, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is allowed from 2:00 p.m. until 5:00 p.m. WEATHER DISCUSSION: A strong upper-level ridge of high pressure remains centered over the Rockies with a warm and dry southwesterly flow aloft over Oregon. The surface thermal trough was still centered just west of the coastline late this morning. Offshore pressure-gradients were slowly weakening, but easterly winds were still gusting to around 30 mph at the western end of the Columbia Gorge, with light easterly winds making it all the way to the coast. Offshore flow has significantly warmed the low-level air mass since yesterday. 5000-foot temperatures over Salem early this morning were in the mid 60s. That will suppress mixing heights today. ODF Sodar, located in the central coast range, was showing offshore flow from near the surface up to 3500 feet late this morning, with south-southwesterly flow above 3500 feet. The upper-level ridge is forecast to shift only slightly eastward today. A reversal of the low-level offshore flow, to onshore, is looking less likely this afternoon, with the thermal trough staying over western Oregon. Winds at the top of the mixing layer are forecast to be south-southeasterly, but persistent low-level offshore flow would decrease the chances for open field-burning this afternoon. Pibals are scheduled to begin at 2 p.m. TODAY'S FORECAST: Sunny and unseasonably warm. Salem's high temperature today will be near 84 degrees (normal is 72). Relative humidity drops below to near 30% by 5 p.m. Surface winds: Variable 3-7 mph this afternoon. Transport winds: ESE 3-6 mph; becoming SSW 6-10 mph this afternoon. Mixing height: Rising to 3000 feet by 3 p.m. and to near 3500 feet by 5 p.m. Salem's sunset tonight: 6:57 p.m. THREE-HOURLY DATA: 2 p.m. 5 p.m. 8 p.m. Temperature: 78 83 68 Relative Humidity: 33% 30% 52% Surface Wind Direction: 360 Var 230 Surface Wind Speed: 5 5 5 Transport Wind Direction: 200 210 180 Transport Wind Speed: 6 10 7 Mixing Height: 2500 3500 1000 Ventilation Index: 15 35 7 EXTENDED DISCUSSION: The upper-level ridge is forecast to weaken and shift eastward on Friday. Increasing southwesterly flow aloft will force the surface thermal trough into eastern Oregon. Onshore flow will cool temperatures back close to normal with increasing clouds. Dry conditions should prevail, with southwesterly transport winds likely allowing for the burning of any remaining fields. Computer models show the first in a series of weather systems coming onshore Saturday. This first system should weaken, as it moves inland, but still bring around one-tenth of an inch of rain. Sunday looks like a mostly dry day, ahead of a much more potent system forecast to come onshore Sunday night. That storm could dump more than one-half inch of rain by Monday evening. An even stronger system is forecast to come onshore late Tuesday. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text 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: -------------- next part -------------- A non-text attachment was scrubbed... Name: Silverton Hills Midday Forecast.doc Type: application/msword Size: 32768 bytes Desc: Silverton Hills Midday Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Thu Sep 29 12:07:56 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 29 Sep 2011 12:07:56 -0700 Subject: [willamette-fcst] Corrected Silverton Hills Midday Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:08 PM PDT THU SEP 29, 2011 Corrected Discussion wording: "south-southeasterly" to "south-southwesterly" BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is allowed from 2:00 p.m. until 5:00 p.m. WEATHER DISCUSSION: A strong upper-level ridge of high pressure remains centered over the Rockies with a warm and dry southwesterly flow aloft over Oregon. The surface thermal trough was still centered just west of the coastline late this morning. Offshore pressure-gradients were slowly weakening, but easterly winds were still gusting to around 30 mph at the western end of the Columbia Gorge, with light easterly winds making it all the way to the coast. Offshore flow has significantly warmed the low-level air mass since yesterday. 5000-foot temperatures over Salem early this morning were in the mid 60s. That will suppress mixing heights today. ODF Sodar, located in the central coast range, was showing offshore flow from near the surface up to 3500 feet late this morning, with south-southwesterly flow above 3500 feet. The upper-level ridge is forecast to shift only slightly eastward today. A reversal of the low-level offshore flow, to onshore, is looking less likely this afternoon, with the thermal trough staying over western Oregon. Winds at the top of the mixing layer are forecast to be south-southwesterly, but persistent low-level offshore flow would decrease the chances for open field-burning this afternoon. Pibals are scheduled to begin at 2 p.m. TODAY'S FORECAST: Sunny and unseasonably warm. Salem's high temperature today will be near 84 degrees (normal is 72). Relative humidity drops below to near 30% by 5 p.m. Surface winds: Variable 3-7 mph this afternoon. Transport winds: ESE 3-6 mph; becoming SSW 6-10 mph this afternoon. Mixing height: Rising to 3000 feet by 3 p.m. and to near 3500 feet by 5 p.m. Salem's sunset tonight: 6:57 p.m. THREE-HOURLY DATA: 2 p.m. 5 p.m. 8 p.m. Temperature: 78 83 68 Relative Humidity: 33% 30% 52% Surface Wind Direction: 360 Var 230 Surface Wind Speed: 5 5 5 Transport Wind Direction: 200 210 180 Transport Wind Speed: 6 10 7 Mixing Height: 2500 3500 1000 Ventilation Index: 15 35 7 EXTENDED DISCUSSION: The upper-level ridge is forecast to weaken and shift eastward on Friday. Increasing southwesterly flow aloft will force the surface thermal trough into eastern Oregon. Onshore flow will cool temperatures back close to normal with increasing clouds. Dry conditions should prevail, with southwesterly transport winds likely allowing for the burning of any remaining fields. Computer models show the first in a series of weather systems coming onshore Saturday. This first system should weaken, as it moves inland, but still bring around one-tenth of an inch of rain. Sunday looks like a mostly dry day, ahead of a much more potent system forecast to come onshore Sunday night. That storm could dump more than one-half inch of rain by Monday evening. An even stronger system is forecast to come onshore late Tuesday. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text 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: -------------- next part -------------- A non-text attachment was scrubbed... Name: Silverton Hills Midday Forecast.doc Type: application/msword Size: 33792 bytes Desc: Silverton Hills Midday Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Fri Sep 30 08:39:15 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 30 Sep 2011 08:39:15 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 8:38 AM PDT FRI SEP 30, 2011 THIS IS THE FINAL FORECAST FOR THE 2011 FIELD-BURNING SEASON BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is allowed from 2:00 p.m. until 5:00 p.m. WEATHER DISCUSSION: A strong upper-level ridge of high pressure remains centered over the Rockies but is shifting eastward, with increasing southwesterly flow aloft over Oregon. The surface thermal trough moved onshore late Thursday and is over the western valleys this morning. Onshore flow has returned to the immediate coastline, but pressure-gradients remain offshore from central Oregon to the Willamette Valley. Surface winds in the valley are light, and the easterly outflow from the Columbia Gorge has stopped. Infrared satellite imagery this morning shows a broad band of mainly middle and high clouds, associated with a weakening frontal system, extending southward from British Columbia across much of Washington and Oregon. Doppler radar was not showing any precipitation from this system. As the upper-level ridge continues to weaken and shift eastward, increasing southwesterly flow aloft will force the surface thermal trough into eastern Oregon this afternoon. Onshore flow will cool temperatures back close to normal. Dry conditions should prevail, with considerable middle and high clouds. Slow cooling aloft should provide better mixing this afternoon with southwesterly transport winds. Today would be a good day to take care of any remaining fields, since a pronounced change to cooler and damp conditions is forecast for next week. TODAY'S FORECAST: Partly sunny and cooler. Salem's high temperature today will be near 77 degrees (normal is 72). Relative humidity drops to 50% by 11 a.m. and to near 40% by 5 p.m. Surface winds: Light; becoming WNW 3-7 mph this afternoon. Transport winds: SSW 3-6 mph this morning; SSW 10-15 mph this afternoon. Mixing height: Rising to 3000 feet by 3 p.m. and to near 4000 feet by 5 p.m. Salem's sunset tonight: 6:55 p.m. THREE-HOURLY DATA: 11 a.m. 2 p.m. 5 p.m. 8 p.m. Temperature: 67 74 77 65 Relative Humidity: 50% 43% 39% 58% Surface Wind Direction: Var 330 300 290 Surface Wind Speed: 3 4 4 5 Transport Wind Direction: 220 220 220 300 Transport Wind Speed: 5 10 15 10 Mixing Height: 1500 3000 4000 1000 Ventilation Index: 8 30 60 10 EXTENDED DISCUSSION: A major shift to autumn-like weather begins this weekend. Computer models show a slightly stronger weather system coming onshore Saturday. It will also weaken but should bring about one-tenth of an inch of rain to the region. Sunday looks mostly dry, ahead of a much more potent system forecast to come onshore Sunday night. The Willamette Valley could pick up more than one-half inch of rain on Monday. An even stronger system is forecast to come onshore late Tuesday. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text 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: -------------- next part -------------- A non-text attachment was scrubbed... Name: Silverton Hills AM Forecast.doc Type: application/msword Size: 32768 bytes Desc: Silverton Hills AM Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Fri Sep 30 11:47:54 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 30 Sep 2011 11:47:54 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 11:45 AM PDT FRI SEP 30, 2011 THIS IS THE FINAL FORECAST FOR THE 2011 FIELD-BURNING SEASON BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is allowed from 2:00 p.m. until 5:00 p.m. WEATHER DISCUSSION: A strong upper-level ridge of high pressure remains centered over the Rockies but is shifting eastward, with increasing southwesterly flow aloft over Oregon. The surface thermal trough moved onshore late Thursday and was still over the western valleys earlier this. However, onshore flow is returning to western Oregon, at midday, with the thermal trough shifting eastward into central Oregon. Winds are light across the Willamette Valley, but southwesterly flow is beginning to penetrate into the Eugene area. Midday infrared satellite imagery shows a broad band of mainly middle and high clouds, associated with the first in a series of weather systems, advancing across Washington and Oregon. Some low clouds were also along the coast, with a few cloud build-ups over the interior of northwestern Oregon. Doppler radar is showing some light rain along the north coast, which is moving into southwestern Washington. Astoria was seeing some light rain late this morning. A few sprinkles have advanced as far inland as Hillsboro. As the upper-level ridge continues to weaken and shift eastward, increasing southwesterly flow aloft will spread considerable middle and high clouds over the region this afternoon. The surface thermal trough will get forced well east of the Cascades, with increasing low-level onshore flow holding maximum temperatures in the 70s. There is a slight chance of a sprinkle, but generally dry conditions should prevail. Slow cooling aloft will yield higher mixing heights this afternoon. Southwesterly transport winds should provide good smoke dispersal conditions for any remaining field-burning. A change to cooler and damp conditions is forecast for next week. TODAY'S FORECAST: Partly sunny and cooler. Salem's high temperature today will be near 77 degrees (normal is 72). Relative humidity drops to near 40% by 5 p.m. Surface winds: WNW 3-7 mph this afternoon. Transport winds: SSW 10-15 mph this afternoon. Mixing height: Rising to 3000 feet by 2 p.m. and to near 4000 feet by 5 p.m. Salem's sunset tonight: 6:55 p.m. THREE-HOURLY DATA: 2 p.m. 5 p.m. 8 p.m. Temperature: 74 77 65 Relative Humidity: 43% 39% 58% Surface Wind Direction: 330 300 290 Surface Wind Speed: 4 4 5 Transport Wind Direction: 220 220 300 Transport Wind Speed: 10 15 10 Mixing Height: 3000 4000 1000 Ventilation Index: 30 60 10 EXTENDED DISCUSSION: A slightly stronger weather system is forecast to bring about one-tenth of an inch of rain to the valley on Saturday. Sunday looks mostly dry, ahead of a much more potent system forecast to come onshore Sunday night. Much of the valley could pick up more than one-half inch of rain on Monday. An even stronger system is forecast to bring more rain and some wind late Tuesday. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text 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: -------------- next part -------------- A non-text attachment was scrubbed... Name: Silverton Hills Midday Forecast.doc Type: application/msword Size: 33280 bytes Desc: Silverton Hills Midday Forecast.doc URL: