From willamette-fcst at listsmart.osl.state.or.us Mon Aug 1 09:19:03 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 1 Aug 2011 09:19:03 -0700 Subject: [willamette-fcst] Silverton Hills Forecast Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT MON AUG 01 2011 BURN ADVISORY: Agricultural burning burning is not recommended. Prep burning is allowed from 12:00pm to 6:00pm with a 50 acre limit. Propane flaming is allowed from 12:00pm to 6:00pm. WEATHER DISCUSSION: A broad but weak upper level trough covers western North America and the northeastern Pacific this morning. Satellite pictures show nearly clear skies over northwestern Oregon with just a few areas of patchy morning fog. Pressure gradients are weakly onshore and should remain onshore throughout the day, although gradient stacking to the east will continue. Low level winds are generally northerly this morning, but should turn more northwesterly this afternoon. The morning Salem sounding was similar to yesterday's morning sounding above 5000 feet but showed some cooling below 3000 feet. This has made the atmosphere a little more stable today. Inversions were noted from about 1700 feet to 2200 feet, from 2900 feet to 3000 feet and from 4100 feet to 4800 feet. With ample heating today these inversions should mix out, however, and the maximum mixing height this afternoon should reach 5000 feet. A 3000 foot mixing height should be reached by about noon. Good mixing heights this afternoon and a potential shift to a more favorable wind direction late this afternoon may provide a burning opportunity. The limiting factor would be gradient stacking east, which implies atmospheric subsidence, which implies smoke hanging up in the Cascades and drifting back into the Willamette Valley during the overnight hours. Winds and pressure gradients will be monitored carefully throughout the day. TODAY'S FORECAST: Sunny and warm. Salem's high temperature today will be near 86. Relative humidity drops to 50% by 10am. Minimum relative humidity 29%. Surface winds: Northerly 4 to 6 mph this morning shifting to northwesterly 6-9 after about 3pm. Transport winds: Northerly about 5 mph this morning gradually backing to northwesterly late this afternoon then westerly at about 5 this evening. Maximum mixing height: 5000 feet. Sunset tonight: 8:39 pm. THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 73 81 85 77 Relative Humidity: 48% 35% 29% 39% Surface Wind Direction: 010 340 310 280 Surface Wind Speed: 4 5 7 7 Transport Wind Direction: 360 340 320 300 Transport Wind Speed: 5 5 5 5 Estimated Mixing Height: 2800 4200 5000 1000 Ventilation Index: 14 21 25 5 EXTENDED DISCUSSION: An onshore flow pattern should continue through the week with minor upper level disturbances moving west to east mostly to the north of the area. This should present occasional burning opportunities that need to be assessed on a day to day basis. Temperatures should be near to slightly above average and no rain is likely through through the week and into the weekend. The National Weather Service's digital forecast is available at http://forecast.weather.gov/MapClick.php?lat=44.905&lon=-122.810. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the equivalent 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. Jim Little ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Mon Aug 1 11:35:30 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 1 Aug 2011 11:35:30 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT MON AUG 01 2011 BURN ADVISORY: Agricultural burning burning is not recommended. Prep burning is allowed from now until 2:00pm with a 50 acre limit. Propane flaming is allowed from now until 6:00pm. WEATHER DISCUSSION: Latest satellite pictures show clear skies over virtually all of Oregon with no evidence yet of thunderstorm development east of the Cascades. Marion County and vicinity temperatures were mostly in the upper 60's and low 70's as of late morning, although an amateur weather station in Sublimity was reporting 76 degrees. Surface wind reports were all light - under 5 mph - and were generally northerly. Pressure gradients remain onshore. Pressure has risin slightly at Newport but has fallen at Redmond during the late morning hours. Pressure gradients as of 11am included: Newport to Salem, 1.3 mb onshore; Salem to Redmond, 2.2 mb onshore; and Newport to Redmond, 3.5 mb onshore. Thus gradient stacking to the east continues. Short range computer models are split on the gradient stacking issue one showing a continuation, the other showing slightly stronger gradients to the west of the Willamette Valley late this afternoon. We will continue to monitor. THIS AFTERNOON'S FORECAST: Sunny and warm. Salem's high temperature today will be near 86. Minimum relative humidity 29%. Surface winds: N 5-7mph slowly backing to NW 7-9 during the afternoon Transport winds: N 5-8 slowly backing to NW during the afternoon Maximum mixing height: 5000 feet Sunset tonight: 8:39 pm THREE-HOURLY DATA: 2pm 5pm 8pm Temperature: 80 85 77 Relative Humidity: 37% 30% 40% Surface Wind Direction: 340 330 300 Surface Wind Speed: 6 7 8 Transport Wind Direction: 340 330 300 Transport Wind Speed: 5 5 5 Estimated Mixing Height: 4200 5000 1000 Ventilation Index: 21 25 5 EXTENDED DISCUSSION: An onshore flow pattern should continue through the week with minor upper level disturbances moving west to east mostly to the north of the area. This should present occasional burning opportunities that need to be assessed on a day to day basis. Temperatures should be near to slightly above average and no rain is likely through through the week and into the weekend. The National Weather Service's digital forecast is available at http://forecast.weather.gov/MapClick.php?lat=44.905&lon=-122.810. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the equivalent 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. Jim Little ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Tue Aug 2 08:24:58 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 2 Aug 2011 08:24:58 -0700 Subject: [willamette-fcst] Silverton Hills Field Burning Forecast Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT TUE AUG 02 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is allowed from 1:00pm to 5:00pm. WEATHER DISCUSSION: A broad but weak upper level trough again covers the northeast Pacific Ocean and the Pacific Northwest. A weak disturbance moving through the trough has brought cloud cover to western Washington and thickened the marine layer along the Oregon Coast. Satellite pictures show scattered mid and high level clouds over the Willamette Valley and thick marine clouds along the coast penetrating inland to the crest of the coast range. A burn opportunity is developing today as the marine air pushes into the Willamette Valley. The morning Salem sounding showed just a very slight cooling since yesterday morning at low levels. At least 5 shallow inversions were noted between the surface and 6000 feet. All but the highest of these should mix out this afternoon as temperatures climb to the 80 degree mark. Winds on the sounding were generally southwesterly. 8am surface pressures showed gradient stacking to the east. The Newport to Salem gradient was 0.8 mb onshore; Salem to Redmond, 2.2 mb onshore; and total Newport to Redmond gradient, 3.0 mb onshore. Gradient stacking to the east should ease as temperatures rise and pressures fall in central Oregon but clouds and fog limit heating along the coast. TODAY'S FORECAST: Partly cloudy and warm. Salem's high temperature today will be near 80. Relative humidity drops to 50% by 11am. Minimum relative humidity 31%. Surface winds: WSW 3-7mph Transport winds: SW 3-6 gradually veering to WNW 4-8 during the afternoon. Mixing heights: The mixing height should reach 3000 feet by 1pm this afternoon and top out at 4000 feet late this afternoon. Sunset tonight: 8:37 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 68 76 80 72 Relative Humidity: 57% 40% 31% 43% Surface Wind Direction: 260 280 290 280 Surface Wind Speed: 3 4 6 7 Transport Wind Direction: 240 290 300 300 Transport Wind Speed: 4 3 6 13 Estimated Mixing Height: 2100 3700 4000 1500 Ventilation Index: 8 11 24 20 EXTENDED DISCUSSION: The general pattern of weak troughiness over the western United states will continue through the week. Weather should stay dry. A marine push today would leave a strong inversion over the valley and strong gradient stacking east would likely preclude burning tomorrow, but the pattern is generally favorable for potential burn opportunities Thursday or Friday. The National Weather Service's digital forecast is available http://forecast.weather.gov/MapClick.php?lat=44.905&lon=-122.810. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the equivalent 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. Jim Little ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Tue Aug 2 11:58:04 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 2 Aug 2011 11:58:04 -0700 Subject: [willamette-fcst] Silverton Hills Forecast - noon update Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT TUE AUG 02 2011 BURN ADVISORY: Agricultural burning burning is not recommended. Prep burning is not allowed. Propane flaming is allowed from 1:00pm to 5:00pm. WEATHER DISCUSSION: A weak upper level disturbance moving through a broad but weak trough has brought mid and high clouds to Washington but only some widely scattered clouds to Oregon. The extensive low cloudiness seen earlier on satellite pictures has mostly dissipated and fair weather is the rule over the region. Temperatures are in the upper 60's and low 70's as of late morning in the central Willamette Valley. Gradient stacking east is still quite strong. As of 11am there was a total of 4.7mb between Newport and Redmond but 3.3mb of that was to the east of Salem and the Newport/Salem gradient was only 1.4 mb. As temperatures warm in the Valley pressures should drop and the gradient stacking should even out somewhat. We will monitor pressures and gradients carefully through the afternoon. THIS AFTERNOON'S FORECAST: Salem's high temperature today will be near 80. Minimum relative humidity today should be about 31%. Surface winds: Mostly westerly this afternoon 5-7mph. Transport winds: Becoming WNW 3-6 and increasing during the early evening. Estimated mixing height as of noon: 2100 feet. Forecast maximum 4000 feet. Sunset tonight: 8:38 pm THREE-HOURLY DATA: 2pm 5pm 8pm Temperature: 77 80 73 Relative Humidity: 40% 34% 44% Surface Wind Direction: 300 300 290 Surface Wind Speed: 5 6 7 Transport Wind Direction: 290 300 300 Transport Wind Speed: 3 6 13 Estimated Mixing Height: 3700 4000 1500 Ventilation Index: 11 24 20 EXTENDED DISCUSSION: The general pattern of weak troughiness over the western United states will continue through the week. Weather should stay dry. A marine push today or tonight would leave a strong inversion over the valley and strong gradient stacking east would likely preclude burning tomorrow, but the pattern is generally favorable for potential burn opportunities Thursday or Friday. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.905&lon=-122.810. The National Weather Service's digital forecast is available http://forecast.weather.gov/MapClick.php?lat=44.905&lon=-122.810. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the equivalent 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. Jim Little ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Wed Aug 3 08:47:56 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 3 Aug 2011 08:47:56 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 8:45 AM PDT WED AUG 3, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is allowed from noon until 5:00 p.m. WEATHER DISCUSSION: Today's weather pattern is very similar to what we saw on Tuesday. A weak upper-level trough is still just offshore with a dry southwesterly flow aloft over western Oregon. Winds below 5000 feet are light and weakly onshore. There was not a significant influx of marine air into the Willamette Valley overnight, with Salem's morning sounding nearly identical to yesterday. Visible satellite imagery shows marine clouds along the northern and central coastline but clear skies over the Willamette Valley. The surface map is indicating that onshore flow is very weak from the coast into a thermal trough, which extends from central Oregon into southwestern Oregon. Onshore gradients should increase this afternoon, as the upper-level trough slowly approaches the coastline. Cooling aloft will yield favorable mixing heights for burning this afternoon, but the strength and direction of transport winds will need to be closely monitored. Light northwesterly winds are forecast, below 5000 feet, with an abrupt shift to SSW winds at the mixing height. TODAY'S FORECAST: Sunny and warm. Salem's high temperature today will be near 84 degrees (normal is 84). Relative humidity drops below 50% by 11 a.m. and to near 30% by 5 p.m. Surface winds: Light this morning; NW 5-10 mph this afternoon. Transport winds: Light SW this morning; NW 4-8 mph this afternoon. Mixing height: Rises to 3000 feet about noon and to 5500 feet by 5 p.m. Salem's sunset tonight: 8:36 p.m. THREE-HOURLY DATA: 11 a.m. 2 p.m. 5 p.m. 8 p.m. Temperature: 70 78 83 74 Relative Humidity: 46% 35% 30% 48% Surface Wind Direction: Var 320 310 300 Surface Wind Speed: 3 4 7 10 Transport Wind Direction: 240 300 310 300 Transport Wind Speed: 3 5 7 15 Mixing Height: 2500 5000 5500 2300 Ventilation Index: 8 25 39 35 EXTENDED DISCUSSION: Some marine air is expected to penetrate into the Willamette Valley beginning this evening. Gradient-stacking may inhibit burning on Thursday, if too much marine air pours into the valley tonight. The weak upper-level trough is forecast to move across western Oregon Thursday, which would otherwise make for favorable burning conditions. A dry westerly flow aloft may also create favorable burning conditions on Friday. Temperatures are only expected to cool a couple of degrees each day. 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: 31744 bytes Desc: Silverton Hills AM Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Wed Aug 3 11:58:13 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 3 Aug 2011 11:58:13 -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 AUG 3, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is allowed from noon until 5:00 p.m. WEATHER DISCUSSION: Late-morning visible satellite imagery showed patchy marine clouds along the northern and central coastline and clear skies over the Willamette Valley. A weak thermal trough extends from central Oregon into south-central Oregon. Onshore gradients are slowly increasing across western Oregon, with Newport to Salem at 1.3mb onshore and Salem to Redmond 1.5mb onshore, as of 11 a.m. Onshore gradients should continue increase this afternoon, as an offshore upper-level trough slowly approaches the coastline. Cooling aloft will yield favorable mixing heights for burning this afternoon. However, considerable shear of the transport winds is likely again today and will be the limiting factor for burning. Light northwesterly low-level winds are forecast to abruptly shift to south-southwesterly near the mixing height this afternoon. Pibals are scheduled to begin at 2 p.m. Increasing onshore flow should rapidly drop mixing heights this evening with northwesterly winds dominating the transport flow. TODAY'S FORECAST: Sunny and warm. Salem's high temperature today will be near 84 degrees (normal is 84). Relative humidity drops to near 30% by 5 p.m. Surface winds: NW 5-10 mph this afternoon. Transport winds: NW 4-8 mph; shifting to SSW 10 mph near the mixing height. Mixing height: Rises 5500 feet by 5 p.m.; then drops to 2300 feet by 8 p.m. Salem's sunset tonight: 8:36 p.m. THREE-HOURLY DATA: 2 p.m. 5 p.m. 8 p.m. Temperature: 78 83 74 Relative Humidity: 35% 30% 48% Surface Wind Direction: 320 310 300 Surface Wind Speed: 4 7 10 Transport Wind Direction: 300 310 300 Transport Wind Speed: 5 7 15 Mixing Height: 5000 5500 2300 Ventilation Index: 25 39 35 EXTENDED DISCUSSION: Gradient-stacking may inhibit burning on Thursday, if too much marine air pours into the valley tonight. Otherwise, conditions for burning should be favorable on Thursday, as a weak upper-level trough moves across western Oregon. A dry westerly flow aloft may create marginal burning conditions on Friday. Temperatures are only expected to cool a couple of degrees each day. 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: 30720 bytes Desc: Silverton Hills Midday Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Thu Aug 4 08:32:54 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 4 Aug 2011 08:32:54 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 8:30 AM PDT THU AUG 4, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is allowed from noon until 5:00 p.m. WEATHER DISCUSSION: Today's weather pattern is very similar to the past two days. A weak upper-level trough is still just offshore with a dry southwesterly flow aloft over western Oregon. Winds below 5000 feet are light and weakly onshore. There was not a significant influx of marine air into the Willamette Valley overnight. In fact, Salem's morning sounding showed slight warming from the surface up through about 11,000 feet. There are some significant changes beginning to show up in the overall weather pattern. The surface map is indicating slightly stronger onshore flow, compared to yesterday morning, across western Oregon. Mid-morning visible satellite imagery shows that marine clouds have penetrated inland into the Umpqua Basin and the southern Willamette Valley. Patchy low clouds were also making their way up the Columbia River into the Portland area. Skies were still mostly clear across Marion and northern Linn Counties. Onshore gradients should further increase today, as the weak upper-level trough finally moves inland. The strength and timing of the increasing onshore flow will need to be monitored closely today. If marine air pours into the valley too quickly, then gradient-stacking may become unfavorable, and surface winds too strong, for burning. If the onshore flow is too weak, then low-level winds may stay northerly, as was the case yesterday. Slight cooling aloft will yield high afternoon mixing heights. TODAY'S FORECAST: Sunny and warm. Patchy morning clouds possible. Salem's high temperature today will be near 85 degrees (normal is 84). Relative humidity drops below 50% by noon and to near 37% by 5 p.m. Surface winds: Light this morning; NNW 5-10 mph this afternoon. Transport winds: Light north this morning; NNW 10 mph this afternoon. Mixing height: Rises to 3000 feet about noon and to 5000 feet by 5 p.m. Salem's sunset tonight: 8:35 p.m. THREE-HOURLY DATA: 11 a.m. 2 p.m. 5 p.m. 8 p.m. Temperature: 73 80 84 74 Relative Humidity: 53% 43% 37% 52% Surface Wind Direction: Var 340 330 300 Surface Wind Speed: 3 6 7 10 Transport Wind Direction: 350 340 340 320 Transport Wind Speed: 3 10 10 15 Mixing Height: 2800 4200 5000 2000 Ventilation Index: 8 42 50 30 EXTENDED DISCUSSION: A dry westerly flow aloft is forecast for Friday, with another weak upper-level trough moving into British Columbia. Moderate onshore flow will keep temperature near normal and could create favorable burning conditions. Expect dry weather, weak onshore flow, and moderate temperatures to continue through at least the first half of next week. Long-range computer models are showing a stronger trough dropping into the region about next Friday. That could create a burning opportunity and also bring some showers to 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 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 Aug 4 12:00:34 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 4 Aug 2011 12:00:34 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 11:50 AM PDT THU AUG 4, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is allowed from noon until 5:00 p.m. WEATHER DISCUSSION: A weak upper-level trough is finally moving onshore today. That has forces the surface thermal trough into Central Oregon and increased the low-level onshore flow into western Oregon. Satellite imagery showed low clouds still blanketing the southern Willamette Valley and Umpqua Basin late this morning. Some low clouds were visible as far north as southern Marion County, with sunshine over the north valley. The marine push into the south valley has resulted in a rather unusual pressure pattern across the Willamette Valley. Gradients are northerly from Portland to Salem and southerly from Eugene to Salem. That is helping to give low-level winds more of a westerly component over southern Marion and extreme northern Linn Counties. That is a pattern more favorable for burning, if it persists into the afternoon. Onshore gradients should further increase today, as the weak upper-level trough moves across western Oregon. Slight cooling aloft will yield high afternoon mixing heights but could also trigger thunderstorm development over the Cascades. Transport winds will need to be monitored closely to see if they have and maintain enough of a westerly component for open burning. In any case, look for an influx of cool marine air to rapidly lower mixing heights this evening. TODAY'S FORECAST: Sunny and warm. Salem's high temperature today will be near 85 degrees (normal is 84). Relative humidity drops to near 37% by 5 p.m. Surface winds: NW 5-10 mph this afternoon. Transport winds: NW 10 mph this afternoon. Mixing height: Rises to 5000 feet by 5 p.m. Salem's sunset tonight: 8:35 p.m. THREE-HOURLY DATA: 2 p.m. 5 p.m. 8 p.m. Temperature: 80 84 74 Relative Humidity: 43% 37% 52% Surface Wind Direction: 340 320 300 Surface Wind Speed: 7 7 10 Transport Wind Direction: 340 330 320 Transport Wind Speed: 10 10 15 Mixing Height: 4200 5000 2000 Ventilation Index: 42 50 30 EXTENDED DISCUSSION: A dry westerly flow aloft is forecast for Friday, with another weak upper-level trough moving into British Columbia. Moderate onshore flow will keep temperatures near normal. There is a slight chance that northerly low-level winds will turn enough onshore to allow for limited afternoon burning. Little change in the weather pattern is forecast through early next week. Long-range computer models are now waffling on their forecasts for late next week, with some showing a fairly strong trough moving onshore and others building a ridge over the west coast. Therefore, confidence in the forecast beyond early next week is low. 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: 31744 bytes Desc: Silverton Hills Midday Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Fri Aug 5 08:58:16 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 5 Aug 2011 08:58:16 -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 AUG 5, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is allowed from noon until 5:00 p.m. WEATHER DISCUSSION: A weak upper-level trough moved inland and across Oregon on Thursday. That turned that flow aloft westerly and initiated a surge of cooler marine air into the Willamette Valley Thursday evening. Visible satellite imagery showed low clouds blanketing all but the extreme southwestern corner of western Oregon this morning. However, some breaks in the clouds were evident over the coastal range. The Salem sounding showed several degrees of cooling, below 6000 feet, compared to 24 hours ago, but the low-level air mass is not saturated through that entire layer. Daytime heating should be sufficient to break up the marine clouds by midday with plenty of afternoon sunshine. The air aloft is still fairly cool, so surface heating should result in high mixing heights again this afternoon. The surface map shows only moderate gradient-stacking this morning, which will likely be overcome this afternoon. The limiting factor for open burning today will most likely be the direction of the transport winds, which are forecast stay mostly northerly. TODAY'S FORECAST: Morning clouds, then mostly sunny and a little cooler. Salem's high temperature today will be near 80 degrees (normal is 84). Relative humidity drops below 60% by noon and to near 50% by 2 p.m. Surface winds: NW 3-8 mph this morning; NNW 5-12 mph this afternoon. Transport winds: NNW 8 mph this morning; NNW 10-15 mph this afternoon. Mixing height: Rises to 3000 feet about noon and to 5000 feet by 5 p.m. Salem's sunset tonight: 8:33 p.m. THREE-HOURLY DATA: 11 a.m. 2 p.m. 5 p.m. 8 p.m. Temperature: 68 75 79 72 Relative Humidity: 63% 50% 42% 55% Surface Wind Direction: 330 340 340 340 Surface Wind Speed: 5 6 8 10 Transport Wind Direction: 340 340 340 340 Transport Wind Speed: 8 10 15 15 Mixing Height: 2800 4200 5500 2800 Ventilation Index: 22 42 83 42 EXTENDED DISCUSSION: Little change in the weather pattern is forecast through early next week. Expect varying degrees of morning clouds with afternoon sunshine and moderate temperatures. Long-range computer models begin to diverge late next week, but that average of their solutions basically maintains the same general weather pattern. Some burning opportunities are possible. 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: 31744 bytes Desc: Silverton Hills AM Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Fri Aug 5 11:58:29 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 5 Aug 2011 11:58:29 -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 AUG 5, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is allowed from noon until 5:00 p.m. WEATHER DISCUSSION: Late-morning visible satellite imagery showed low clouds continuing to cover the Willamette Valley and the north coast. However, skies had cleared along the central coast and were beginning to clear over the northern and central coastal range. The surface map showed high pressure building into northwestern Oregon with weak northerly gradients across western Oregon. With a fresh supply of cool marine air and cloudy skies over the Willamette Valley, gradient-stacking has worsened slightly since this morning. Newport-Salem was 0.4mb onshore with Salem-Redmond 3.5mb onshore. It will take at least a couple hours of sunshine over the Willamette Valley to level those gradients. The air aloft is still fairly cool, so mixing heights will be high, once we get some warming August sunshine to the valley floors. Another limiting factor for open burning today will be the direction of the transport winds, which are forecast stay mostly northerly. TODAY'S FORECAST: Low clouds giving way to mostly sunny skies mid-afternoon. Cooler. Salem's high temperature today will be near 79 degrees (normal is 84). Relative humidity drops to near 50% by 3 p.m. Surface winds: NNW 5-12 mph this afternoon. Transport winds: NNW 10-15 mph this afternoon. Mixing height: Rises to 5500 feet by 5 p.m. Salem's sunset tonight: 8:33 p.m. THREE-HOURLY DATA: 2 p.m. 5 p.m. 8 p.m. Temperature: 73 78 72 Relative Humidity: 52% 44% 55% Surface Wind Direction: 340 340 340 Surface Wind Speed: 6 8 10 Transport Wind Direction: 340 340 340 Transport Wind Speed: 10 15 15 Mixing Height: 4000 5500 2800 Ventilation Index: 40 83 42 EXTENDED DISCUSSION: Little change in the weather pattern is forecast through early next week. Expect varying degrees of morning clouds with afternoon sunshine and moderate temperatures. That may create some limited burning opportunities much like we have seen this 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: 31232 bytes Desc: Silverton Hills Midday Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Mon Aug 8 08:19:14 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 8 Aug 2011 08:19:14 -0700 Subject: [willamette-fcst] Silverton Hills Forecast Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT MON AUG 08 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is allowed from 12:30pm to 5:00pm with a 50 acre limit. Propane flaming is allowed from 12:30pm to 5:00pm. WEATHER DISCUSSION: In the upper atmosphere flow is very light with a weak trough off the Oregon and northern California coastline. The morning ODF surface analysis shows onshore flow with a thermal trough in the central valley of California and another thermally induced trough centered in eastern Washington extending southward into central Oregon. The morning Salem sounding showed a marine layer similar to yesterday - topping out around 3500 feet. The cloud layer is much thinner, however, with bases around 1900 feet and top sat about 2300 feet. The clouds should begin to breakup later this morning and by noon expect mostly sunny skies. The morning sounding showed a more unstable atmosphere (compared to yesterday) above the marine layer and with the weak trough offshore moving eastward there's a good chance of isolated afternoon or evening thunderstorms over the southern and central Oregon Cascades. The weather pattern is conducive to northerly winds all day and computer models show just that: winds north or north-northeast through most of the transport layer then backing to very light west-southwest at the top of the mixing layer and above. Conditions are not favorable for good smoke evacuation to the east today. If any opportunity arose it wouldn't be until early evening and then it would be marginal at best. TODAY'S FORECAST: Morning clouds, mostly sunny by afternoon. Slight chance of thunderstorms over the Cascades. Salem's high temperature today will be near 80. Relative humidity drops to 50% by 11am. Minimum relative humidity 35%. Surface winds: N 4-7 mph slowly becoming NW 4-7 late afternoon or early evening. Transport winds: N 5 mph slowly becoming NW 5-9 late afternoon or early evening. Maximum mixing height: 4100 feet. Sunset tonight: 8:29 pm THREE-HOURLY DATA: 11am 2pm 5pm 8pm Temperature: 69 76 80 72 Relative Humidity: 55% 40% 35% 46% Surface Wind Direction: 350 340 330 290 Surface Wind Speed: 5 6 7 8 Transport Wind Direction: 350 350 340 300 Transport Wind Speed: 5 5 5 9 Estimated Mixing Height: 2800 3800 4100 1000 Ventilation Index: 14 19 20 9 EXTENDED DISCUSSION: Forecast charts indicate Tuesday will be similar to today as a second weak upper level trough moves in from the west. At this point computer models do not show any significant switch to a more westerly transport flow with this feature. Weak upper level ridging should limit the morning marine clouds later in the week, but a northerly transport wind pattern will continue through the week for very limited, if any, burn opportunities. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.905&lon=-122.810. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the equivalent 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. Jim Little ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Mon Aug 8 11:43:55 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 8 Aug 2011 11:43:55 -0700 Subject: [willamette-fcst] Silverton Hills Forecast - Noon Update Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT MON AUG 08 2011 BURN ADVISORY: Agricultural burning burning is not recommended. Prep burning is allowed from 12:30pm to 3:00pm with a 50 acre limit. Propane flaming is allowed from 12:30pm to 5:00pm. WEATHER DISCUSSION: A weak upper level trough is swinging over the Pacific Northwest today. The marine layer is hanging tough and late morning satellite pictures show very few breaks. Consequently valley temperatures have been slow to warm, with low to mid 60's common throughout the region as of late morning. I have lowered the forecast high temperature for today. Strong gradient stacking continues and is unlikely to even out this afternoon. Pressure gradients as of 11am included: Newport to Salem, just 0.9 mb onshore; Salem to Redmond, 4.2 mb onshore; total Newport to Redmond, 5.1 mb onshore. Meanwhile the Portland to Medford gradient was 4.3 mb northerly. Latest models are a bit more optimistic about transport winds with more northwest than shown earlier. However the University of Washington models show winds actually going light northeasterly above a couple thousand feet by about sunset. This may reflect the possibility of thunderstorm buildups over the Cascades later this afternoon. In any case northeasterly winds developing in the transport region would argue against allowing any burning this afternoon. THIS AFTERNOON'S FORECAST: Cloudy through early afternoon then partly cloudy. Salem's high temperature today will be near 77. (Average: 85) Minimum relative humidity will be about 40%. Surface winds: N to NW 6-10. Transport winds: N-NNW 5 becoming NW 8-10 late afternoon or early evening. Maximum mixing height: 3900 Sunset tonight: 8:29 pm THREE-HOURLY DATA: 2pm 5pm 8pm Temperature: 71 77 70 Relative Humidity: 53% 40% 49% Surface Wind Direction: 340 330 300 Surface Wind Speed: 6 8 10 Transport Wind Direction: 350 340 300 Transport Wind Speed: 5 5 9 Estimated Mixing Height: 3400 3900 1000 Ventilation Index: 19 20 9 EXTENDED DISCUSSION: Latest forecast charts show another weak upper level low approaching the Pacific Northwest tomorrow for a very similar weather pattern to today's. At this point computer models do not show any significant switch to a more westerly transport flow with this feature. Weak upper ridging should limit the morning marine clouds later in the week, but a northerly transport wind pattern will continue through the week for very limited, if any, burn opportunities. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.905&lon=-122.810. Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the equivalent 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. Jim Little ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Tue Aug 9 08:20:02 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 09 Aug 2011 10:20:02 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Tue, Aug 09 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 Aug 9 11:33:48 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 09 Aug 2011 13:33:48 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Tue, Aug 09 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 Aug 10 08:32:56 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 10 Aug 2011 10:32:56 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Wed, Aug 10 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 Aug 10 11:45:43 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 10 Aug 2011 13:45:43 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Wed, Aug 10 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 Aug 11 08:52:29 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 11 Aug 2011 08:52:29 -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 THU AUG 11, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is allowed from noon until 2 p.m. with a 50 acre limit. Propane flaming is allowed from noon until 5:00 p.m. WEATHER DISCUSSION: Infrared satellite imagery shows some high clouds, associated with a weak upper-level disturbance, moving onto the northern Washington coast this morning. Visible satellite imagery showed low clouds covering virtually all of western Washington; extending southward into the northwestern Oregon. A few low clouds had made their way into the northern Willamette Valley, north of Marion County, with clear skies over central and southern valley. A weak westerly flow aloft will send a dry upper-level disturbance onshore this afternoon. That will maintain weak onshore flow and bring a similar day to what we saw on Wednesday. The Salem sounding this morning showed some minor warming, below 5000 feet, which will slightly retard the rise in daytime mixing heights, compared to yesterday. The air aloft is still cool enough for surface heating to produce high mixing heights again this afternoon. The surface map shows only very weak onshore flow, which may increase enough this afternoon to allow for limited burning. Transport winds are forecast to maintain a significant northerly component and will need to be monitored closely. TODAY'S FORECAST: Sunny. Salem's high temperature today will be near 84 degrees (normal is 83). Relative humidity drops below 60% by 11 a.m. and to near 33% by 5 p.m. Surface winds: N 5 mph this morning; NNW 5-10 mph this afternoon. Transport winds: N 5 mph this morning; NNW 6-10 mph this afternoon. Mixing height: Rises to 3000 feet about noon and to 5000 feet by 5 p.m. Salem's sunset tonight: 8:25 p.m. THREE-HOURLY DATA: 11 a.m. 2 p.m. 5 p.m. 8 p.m. Temperature: 68 78 82 74 Relative Humidity: 57% 39% 33% 45% Surface Wind Direction: 360 340 340 310 Surface Wind Speed: 5 6 8 9 Transport Wind Direction: 360 340 340 340 Transport Wind Speed: 5 6 8 10 Mixing Height: 2800 4200 5000 2500 Ventilation Index: 14 25 40 25 EXTENDED DISCUSSION: The dry upper-level flow is forecast to increase and turn southwesterly on Friday, as a fairly strong trough drops into the Gulf of Alaska. That should slightly increase the onshore flow, which could create another limited burning opportunity. The longer-range computer models differ on the timing and strength of a trough forecast to come onshore early next week. Some models bring it inland on Sunday, but others delay it until late Monday or Tuesday, which would be more favorable for early-week burning. Some showers are possible with this system, but that is also in question 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: 31744 bytes Desc: Silverton Hills AM Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Thu Aug 11 11:57:18 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 11 Aug 2011 11:57:18 -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 AUG 11, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is allowed from noon until 2 p.m. with a 50 acre limit. Propane flaming is allowed from noon until 5:00 p.m. WEATHER DISCUSSION: Infrared satellite imagery revealed bands of high clouds cutting across northwestern Washington, late this morning, in response to a very weak upper-level disturbance just offshore. Visible satellite imagery showed low clouds still covering much of western Washington and extending southward over the northwestern corner of Oregon. Some low clouds had even made it into the central and southern Willamette Valley since the mid-morning report. The late-morning surface map showed mostly northerly pressure-gradients across the Willamette Valley with most of the onshore flow between Salem and Redmond. That is not a favorable pattern for evacuating smoke from the valley, even with high afternoon mixing heights expected. Daytime heating will help to balance the weak onshore flow, across western Oregon, but surface and transport winds are forecast to remain mostly northerly. TODAY'S FORECAST: Sunny. Salem's high temperature today will be near 84 degrees (normal is 83). Relative humidity drops to near 35% by 5 p.m. Surface winds: N 5-10 mph this afternoon; NW 6-12 mph this evening. Transport winds: NNW 6-12 mph this afternoon. Mixing height: Rises to 3000 feet about noon and to 5000 feet by 5 p.m. Salem's sunset tonight: 8:25 p.m. THREE-HOURLY DATA: 2 p.m. 5 p.m. 8 p.m. Temperature: 78 82 74 Relative Humidity: 41% 35% 46% Surface Wind Direction: 350 350 320 Surface Wind Speed: 6 8 9 Transport Wind Direction: 350 350 350 Transport Wind Speed: 6 10 12 Mixing Height: 4200 5000 2500 Ventilation Index: 25 50 30 EXTENDED DISCUSSION: The dry upper-level flow is forecast to increase and turn southwesterly on Friday, as a fairly strong trough drops into the Gulf of Alaska. Skies will remain mostly sunny with little change in temperatures. Increasing onshore flow may create more favorable burning conditions in the afternoon. Further strengthening of the southwesterly flow aloft is forecast over the weekend, as a broad upper-lever trough, in the Gulf of Alaska, slowly moves closer to our coastline. Look for an increase in marine clouds and a few degrees of cooling each day. Timing of the arrival of the upper-level trough is not certain, but it appears as if a significant surge of onshore flow is likely by Tuesday, which may produce some drizzle or light showers. Ahead of the trough, there is a chance for a burning opportunity on Monday. 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: 31744 bytes Desc: Silverton Hills Midday Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Fri Aug 12 08:44:11 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 12 Aug 2011 08:44:11 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 8:40 AM PDT FRI AUG 12, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is allowed from 2 p.m. until 5:00 p.m. WEATHER DISCUSSION: The upper-level flow has turned southwesterly, with a fairly strong trough dropping into the Gulf of Alaska. At the surface, a weak thermal trough extends from central Washington to southwestern Oregon with north-northwesterly gradients across western Oregon. Onshore flow has strengthened along the coast but is still weak in the western interior. Visible satellite imagery shows low clouds along the entire Oregon coastal strip this morning with some penetration into the coastal mountain gaps and up the Columbia River into the Portland area. Skies were clear from Marion County southward across the Willamette Valley. Salem's sounding this morning showed a few degrees of warming, below 6000 feet, compared to 24 hours ago. That will make for slightly lower mixing heights and warmer surface temperatures today. As the southwesterly flow aloft increases this afternoon, so will the low-level onshore flow. Unlike yesterday, computer models are forecasting northerly transport winds to back to northwesterly by mid-afternoon, which would be more favorable for smoke evacuation from the valley. Some marine air is forecast to penetrate into the Willamette Valley this evening, which would rapidly lower mixing heights. TODAY'S FORECAST: Sunny. Salem's high temperature today will be near 85 degrees (normal is 83). Relative humidity drops below 50% by 11 a.m. and to near 30% by 5 p.m. Surface winds: N 5 mph this morning; NW 5-10 mph this afternoon. Transport winds: N 5-8 mph this morning; NW 6-10 mph this afternoon. Mixing height: Rises to 3000 feet by 2 p.m. and to 4000 feet by 5 p.m. Salem's sunset tonight: 8:23 p.m. THREE-HOURLY DATA: 11 a.m. 2 p.m. 5 p.m. 8 p.m. Temperature: 71 80 84 74 Relative Humidity: 50% 37% 30% 45% Surface Wind Direction: 360 350 330 300 Surface Wind Speed: 5 6 7 9 Transport Wind Direction: 360 340 320 300 Transport Wind Speed: 7 8 8 13 Mixing Height: 2100 3200 4000 2000 Ventilation Index: 15 26 32 26 EXTENDED DISCUSSION: Further strengthening of the southwesterly flow aloft is forecast over the weekend, as a broad upper-lever trough, in the Gulf of Alaska, slowly moves closer to our coastline. Expect an increase in morning marine clouds and several degrees of cooling on Saturday. A fairly impressive summer cold front is forecast to spread light rain onto the northern Oregon coast by Sunday evening and likely into the Willamette Valley by Monday. Valley rainfall amounts, on Monday, could be on the order of one-tenth of an inch. Dry weather is forecast to quickly return, on Tuesday, with a more typical summertime pattern of morning clouds and afternoon sunshine for the remainder 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: 32256 bytes Desc: Silverton Hills AM Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Fri Aug 12 11:56:51 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 12 Aug 2011 11:56:51 -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 AUG 12, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is allowed from 2 p.m. until 5:00 p.m. WEATHER DISCUSSION: A dry southwesterly flow aloft will bring sunshine and average mid-August temperatures to the Willamette Valley again this afternoon. However, a significant trough is dropping into the Gulf of Alaska and will bring cooler temperatures over the weekend and a good chance of light rain by Monday. The mainly coastal marine low clouds were beginning to dissipate late this morning with generally sunny skies over the Willamette Valley. The late-morning surface map continues to show a weak thermal trough extending from central Washington to southwestern Oregon with slowly increasing north-northwesterly gradients across western Oregon. The orientation of the onshore pressure-gradients is favorable for burning today. The question will be whether to transport winds assume enough of a westerly component for valley smoke evacuation. Slightly warmer temperatures aloft will suppress mixing somewhat this afternoon, but warmer surface temperatures should help maximum mixing heights reach 4000 feet late in the day. As the southwesterly flow aloft increases this afternoon, so will the low-level onshore flow. Computer models are forecasting northerly transport winds to slowly back to north-northwesterly this afternoon, which would be more favorable for valley smoke evacuation. Potentially shifting transport winds will need to be monitored closely today, and pibals are scheduled to begin at 1 p.m. Marine air is forecast to penetrate into the Willamette Valley this evening, which would rapidly lower mixing heights. TODAY'S FORECAST: Sunny and warmer. Salem's high temperature today will be near 84 degrees (normal is 83). Relative humidity drops to near 30% by 5 p.m. Surface winds: N 5 mph; backing to NW 5-10 mph this afternoon. Transport winds: N 5-8 mph; backing to NW 6-10 mph this afternoon. Mixing height: Rises to 3000 feet by 2 p.m. and to 4000 feet by 5 p.m. Salem's sunset tonight: 8:23 p.m. THREE-HOURLY DATA: 2 p.m. 5 p.m. 8 p.m. Temperature: 79 83 74 Relative Humidity: 38% 31% 45% Surface Wind Direction: 355 345 320 Surface Wind Speed: 6 7 9 Transport Wind Direction: 350 335 310 Transport Wind Speed: 8 8 13 Mixing Height: 3200 4000 2000 Ventilation Index: 26 32 26 EXTENDED DISCUSSION: Further strengthening of the southwesterly flow aloft is forecast over the weekend, as a broad upper-lever trough, in the Gulf of Alaska, slowly moves closer to our coastline. Expect an increase in marine clouds and several degrees of cooling both days. An active cold front is forecast to spread light rain onto the northern Oregon coast by Sunday evening and likely into the Willamette Valley by Monday. Valley rainfall amounts, on Monday, could be on the order of one-tenth of an inch. Dry weather is forecast to return, on Tuesday, and persist through 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 Aug 15 08:28:48 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 15 Aug 2011 10:28:48 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Mon, Aug 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 Mon Aug 15 11:47:06 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 15 Aug 2011 13:47:06 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Mon, Aug 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 Tue Aug 16 08:21:44 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 16 Aug 2011 10:21:44 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Tue, Aug 16 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 Aug 16 11:35:25 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 16 Aug 2011 13:35:25 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Tue, Aug 16 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 Aug 17 08:58:17 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 17 Aug 2011 08:58:17 -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 WED AUG 17, 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: There has been very little change to the overall weather pattern for the past few weeks. A massive upper-level ridge remains anchored over the south-central United States with a general weak trough off the west coast. That is resulting in a dry southwesterly flow aloft over Oregon, with the main jet stream in its usual summer-time location over Canada. Satellite imagery showed only a few patches of low clouds along the coast this morning with clear skies over the remainder of Oregon. At the surface, a broad thermal trough extends from central Washington through southwestern Oregon with weak northwesterly pressure-gradients across western Oregon. This morning's sounding over Salem continued to show a very dry and stable air mass with some minor warming aloft compared to yesterday. A weak upper-level disturbance is forecast to cut across southern British Columbia this afternoon and slightly increase the onshore flow into western Oregon. Temperatures will likely start off warmer than on Tuesday but cap out at about the same place, due to minor cooling aloft in the afternoon. Mixing heights will be slow to rise but eventually climb above 4000 feet with the combination of cooling aloft and strong afternoon heating. Pressure-gradient stacking should be favorable for burning this afternoon, with transport wind direction being the limiting factor. Computer models show northerly winds this morning shifting slightly to the northwest this afternoon. Winds will need to be monitored closely for the possibility of limited open burning later this afternoon. A sea breeze will rapidly lower mixing heights this evening with some marine air expected to penetrate into the Willamette Valley overnight. TODAY'S FORECAST: Sunny and warm. Salem's high temperature today will be near 86 degrees (normal is 82). Relative humidity drops below 50% by 11 a.m. and to near 25% by 5 p.m. Surface winds: N 5 mph this morning; NNW 5-10 mph this afternoon. Transport winds: N 5 mph this morning; NNW 6-10 mph this afternoon. Mixing height: Rises to 3000 feet by 1 p.m. and to 4700 feet by 5 p.m. Salem's sunset tonight: 8:15 p.m. THREE-HOURLY DATA: 11 a.m. 2 p.m. 5 p.m. 8 p.m. Temperature: 72 82 85 74 Relative Humidity: 44% 28% 24% 38% Surface Wind Direction: 360 350 340 320 Surface Wind Speed: 5 6 7 9 Transport Wind Direction: 360 345 340 330 Transport Wind Speed: 5 7 9 14 Mixing Height: 2200 3700 4700 2000 Ventilation Index: 11 26 42 28 EXTENDED DISCUSSION: A very weak upper-level trough will be over Oregon on Thursday with onshore flow likely strong enough to bring at least some morning marine clouds into the Willamette Valley. Skies should clear in the afternoon with daytime highs around 80 degrees. Gradient-stacking will be less favorable for burning and transport winds are forecast to return to northerly in the afternoon. Little change is forecast for Friday. An upper-level ridge is forecast to build over Oregon this weekend and likely produce the warmest temperatures so far this summer. Valley temperatures could climb into the low 90s, by Sunday, with north to northeasterly winds. When the upper-level ridge shifts east of the state, early next week, increasing onshore flow could create 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: 32768 bytes Desc: Silverton Hills AM Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Wed Aug 17 11:58:20 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 17 Aug 2011 11:58:20 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 11:57 AM PDT WED AUG 17, 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: Oregon remains under the influence of a dry southwesterly flow aloft. Late-morning satellite imagery showed clear skies over the state. Willamette Valley temperatures were in the low 70s (about 1-3 degrees warmer than 24 hours ago). The surface map showed a broad thermal trough extending from central Washington, through central Oregon, into southwestern Oregon. That was combining with high pressure, centered offshore, to produce northwesterly pressure-gradients across the Willamette Valley. A weak upper-level disturbance is forecast to cut across southern British Columbia late this afternoon and evening; increasing the onshore flow into western Oregon. That should cap valley temperatures in the mid 80s (close to where they peaked on Tuesday). With warm air aloft, mixing heights will be slow to rise this afternoon but should eventually climb above 4000 feet. There was only minor gradient-stacking late this morning, with Newport-to-Salem at 1.5mb onshore and Salem-to-Redmond at 2.3mb onshore. Afternoon heating should be more than enough to balance that out. However, transport winds may not turn enough onshore to allow for open burning. The latest computer guidance shows northerly winds, through early this afternoon, with only a slight shift to NNW by late this afternoon. A sea breeze will rapidly lower mixing heights this evening with some marine air expected to penetrate up the Columbia River and into the northern Willamette Valley overnight. TODAY'S FORECAST: Sunny and warm. Salem's high temperature today will be near 86 degrees (normal is 82). Relative humidity drops to near 25% by 5 p.m. Surface winds: Becoming NNW 5-10 mph this afternoon. Transport winds: Becoming NNW 6-10 mph this afternoon. Mixing height: Rises to 3000 feet by 1 p.m. and to 4700 feet by 5 p.m. Salem's sunset tonight: 8:15 p.m. THREE-HOURLY DATA: 2 p.m. 5 p.m. 8 p.m. Temperature: 82 85 74 Relative Humidity: 28% 24% 38% Surface Wind Direction: 350 340 320 Surface Wind Speed: 6 7 9 Transport Wind Direction: 350 340 330 Transport Wind Speed: 7 9 14 Mixing Height: 3700 4700 2000 Ventilation Index: 26 42 28 EXTENDED DISCUSSION: A very weak upper-level trough will be over Oregon on Thursday with onshore flow likely strong enough to bring at least some morning marine clouds into the Willamette Valley. Skies should clear in the afternoon with daytime highs around 80 degrees. Gradient-stacking will be less favorable for burning and transport winds are forecast to return to northerly in the afternoon. Little change is forecast for Friday. An upper-level ridge is forecast to build over Oregon this weekend; likely producing the warmest weather so far this summer. Valley temperatures could climb into the low 90s, by Sunday, with north to northeasterly winds. The upper-level ridge will shift east of the state early next week. Increasing onshore flow could create burning opportunities. It is also possible that the flow aloft may turn enough southerly to introduce a chance of thunderstorms over the Cascades, which is not helpful for open burning. 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 Thu Aug 18 08:53:17 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 18 Aug 2011 08:53:17 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 8:50 AM PDT THU AUG 18, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is allowed from noon until 2:00 p.m. with a 50 acre limit. Propane flaming is allowed from noon until 5:00 p.m. WEATHER DISCUSSION: A weak upper-level disturbance is cut across southern British Columbia Wednesday afternoon and increased the onshore flow into western Oregon. Visible satellite imagery this morning showed that marine low clouds had moved inland, up the Columbia River, into the northern Willamette Valley. Some low clouds had pushed about as far south as the Silverton Hills. With the influx of cooler marine air overnight, there is some minor gradient-stacking this morning, with Newport-to-Salem at 0.6mb onshore and Salem-to-Redmond at 2.4mb onshore. Westerly flow aloft is forecast for today, as a weak upper-level disturbance moves over western Washington. Morning clouds will give way to a few high clouds in the afternoon. Daytime heating should be enough to balance out the onshore gradients, but transport winds will need to be monitored closely and may stay too northerly to allow for open burning. A weak sea breeze will lower mixing heights this evening with some marine air expected to penetrate up the Columbia River and into the northern Willamette Valley again overnight. TODAY'S FORECAST: Some morning low clouds, then mostly sunny. A little cooler. Salem's high temperature today will be near 81 degrees (normal is 82). Relative humidity drops to 50% by 11 a.m. and to near 33% by 5 p.m. Surface winds: N 5-10 mph this morning; NNW 8-12 mph this afternoon. Transport winds: N 10 mph this morning; NNW 10-15 mph this afternoon. Mixing height: Rises to 3000 feet by noon and to 4700 feet by 5 p.m. Salem's sunset tonight: 8:14 p.m. THREE-HOURLY DATA: 11 a.m. 2 p.m. 5 p.m. 8 p.m. Temperature: 68 76 79 71 Relative Humidity: 50% 39% 33% 48% Surface Wind Direction: 360 350 340 320 Surface Wind Speed: 5 8 9 9 Transport Wind Direction: 360 350 340 340 Transport Wind Speed: 10 12 14 16 Mixing Height: 2700 3500 4700 2000 Ventilation Index: 27 42 66 32 EXTENDED DISCUSSION: A very weak upper-level trough will remain over Oregon on Friday with onshore flow likely strong enough to bring at least some morning marine clouds into the northern Willamette Valley. Otherwise, skies will be sunny with transport winds likely remaining too northerly for open burning. An upper-level flow will turn south-southwesterly this weekend; likely producing the warmest weather so far this summer. Valley temperatures could be near 90 degrees, with north to northeasterly winds. Some thunderstorm development is possible over the Cascades. A weak cold front is forecast to move into southern British Columbia and northwestern Washington early next week, which may turn transport winds enough onshore to create a 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 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 Aug 18 11:56:17 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 18 Aug 2011 11:56:17 -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 AUG 18, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is allowed from noon until 2:00 p.m. with a 50 acre limit. Propane flaming is allowed from noon until 5:00 p.m. WEATHER DISCUSSION: Westerly flow aloft is forecast for today, as a weak upper-level disturbance moves over western Washington. Late-morning visible satellite imagery showed low clouds from the north coast, up the Columbia River, into the extreme northern Willamette Valley. Skies were rapidly clearing over Marion County. The surface map showed high pressure centered offshore with a little stronger northerly pressure-gradients across western Oregon than 24 hours ago. With the morning influx of cooler marine air, there is some gradient-stacking across western Oregon late this morning. That is an indication that air is generally sinking over the region. The latest gradients are: Newport-to-Salem at 0.7mb onshore and Salem-to-Redmond at 2.8mb onshore. The gradient-stacking will likely reverse by late this afternoon, but transport winds may remain too northerly for open burning. Pibal readings will begin 2 p.m. A weak sea breeze will lower mixing heights this evening with some marine air expected to penetrate into the northern Willamette Valley again overnight. TODAY'S FORECAST: Mostly sunny but cooler. Salem's high temperature today will be near 80 degrees (normal is 82). Relative humidity drops to near 33% by 5 p.m. Surface winds: N 10 mph; becoming NNW 8-12 mph late this afternoon. Transport winds: N 12 mph; becoming NNW 12-16 mph late this afternoon. Mixing height: Rises to 3000 feet by noon and to 4700 feet by 5 p.m. Salem's sunset tonight: 8:14 p.m. THREE-HOURLY DATA: 2 p.m. 5 p.m. 8 p.m. Temperature: 75 79 71 Relative Humidity: 42% 33% 48% Surface Wind Direction: 360 350 320 Surface Wind Speed: 8 10 9 Transport Wind Direction: 360 345 340 Transport Wind Speed: 12 14 16 Mixing Height: 3500 4700 2000 Ventilation Index: 42 66 32 EXTENDED DISCUSSION: Little change in the weather pattern is forecast for Friday, with a very weak upper-level trough remaining over Oregon. Onshore flow will likely bring at least some morning marine clouds into the northern Willamette Valley. Otherwise, skies will be sunny with northerly transport winds. The upper-level flow will turn south-southwesterly on Saturday with valley temperatures approaching 90 degrees. Some thunderstorm development is possible over the Cascades. The flow aloft is forecast to turn westerly on Sunday, with increasing onshore flow capping temperatures in the upper 80s. A cold front is forecast to move into southern British Columbia and northwestern Washington on Monday. It is a long way out, but the current forecast of west-southwesterly transport winds could provide very favorable burning conditions Monday 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: 32256 bytes Desc: Silverton Hills Midday Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Fri Aug 19 08:57:58 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 19 Aug 2011 08:57:58 -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 AUG 19, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is allowed from 11:00 a.m. until 5:00 p.m. WEATHER DISCUSSION: A dry and seasonably warm weather pattern has established itself over the Pacific Northwest. A very weak upper-level trough remains over this morning with light winds aloft. At the surface, high pressure is centered offshore with a thermal trough beginning to build northward, from California, into southwestern Oregon. That has weakened the onshore flow with increasingly northerly pressure-gradients across western Oregon. Visible satellite imagery showed only patchy low clouds on the north coast and up the Columbia River into the Portland area. Elsewhere, skies were clear. A few low clouds could form as far south as the Silverton Hills but should quickly dissipate with daytime heating. This morning's Salem sounding was almost identical to 24 hours ago, with north to north-easterly winds from the surface up to 5000 feet. Warming aloft is forecast today, as the weak upper-level trough over the state sags southwestward to over northwestern California. That will allow temperatures to climb into the middle 80s. Pressure gradients are forecast to remain northerly, with increasing wind speeds this afternoon. TODAY'S FORECAST: Sunny and warmer. Salem's high temperature today will be near 85 degrees (normal is 82). Relative humidity drops to near 60% by 11 a.m. and to near 35% by 5 p.m. Surface winds: N 5-10 mph this morning; N 8-12 mph this afternoon. Transport winds: NNE 10-15 mph this morning; NNE 12-20 mph this afternoon. Mixing height: Rises to 3000 feet by noon and to 4500 feet by 5 p.m. Salem's sunset tonight: 8:12 p.m. THREE-HOURLY DATA: 11 a.m. 2 p.m. 5 p.m. 8 p.m. Temperature: 69 79 84 77 Relative Humidity: 61% 44% 35% 45% Surface Wind Direction: 360 010 360 360 Surface Wind Speed: 8 10 10 9 Transport Wind Direction: 010 010 010 360 Transport Wind Speed: 12 15 20 16 Mixing Height: 2800 3800 4500 2500 Ventilation Index: 34 57 90 40 EXTENDED DISCUSSION: With a weak cut-off upper-level trough centered over northwestern California, the upper-level flow will turn weakly south-southwesterly on Saturday. That will further warm the air mass with valley temperatures approaching 90 degrees. Some mid-level moisture could circulate far enough northward for isolated thunderstorm development over the Cascades, especially south. The system over northern California will continue to weaken on Sunday, and Oregon will come under the influence of a continued dry and more stable westerly flow aloft. The air mass will remain quite warm, with similar temperatures to Saturday. A weakening cold front is forecast to move into southern British Columbia, and extreme northwestern Washington, on Monday. That will increase the onshore flow and could create favorable burning conditions Monday afternoon. The front is forecast to stall and weaken, well north of the region, on Tuesday, with the flow aloft warming and turning more southerly. South-southwesterly flow aloft is forecast for the middle of next week, which will warm temperatures into the middle and upper 80s and circulate enough moisture into the region for a chance of thunderstorms, mainly over the Cascades. It is possible that a weather system will turn the flow more southwesterly by Friday, which would push the thunderstorm threat eastward and possibly create a 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 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 Aug 19 11:58:18 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 19 Aug 2011 11:58:18 -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 AUG 19, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is allowed from now until 5:00 p.m. WEATHER DISCUSSION: A dry and seasonably warm weather pattern has established itself over the Pacific Northwest. A very weak upper-level trough remains over Oregon with light westerly winds aloft. At the surface, high pressure is centered offshore with a thermal trough beginning to build northward, from California, into southwestern Oregon. Onshore pressure-gradients have weakened and turned mostly northerly across western Oregon. Visible satellite imagery showed only low clouds on the north coast and clear skies over the remainder of Oregon. Minor warming aloft is forecast today, as the weak upper-level trough over the state sags southwestward to over northwestern California. That will allow temperatures to climb into the middle 80s. Pressure gradients are forecast to remain northerly today with some increase in wind speeds. Northerly winds will be verified with a pibal reading at 2:00 p.m. TODAY'S FORECAST: Sunny and warmer. Salem's high temperature today will be near 85 degrees (normal is 82). Relative humidity drops to near 35% by 5 p.m. Surface winds: N 8-12 mph this afternoon. Transport winds: NNE 12-20 mph this afternoon. Mixing height: Rises to 4500 feet by 5 p.m. Salem's sunset tonight: 8:12 p.m. THREE-HOURLY DATA: 2 p.m. 5 p.m. 8 p.m. Temperature: 79 84 77 Relative Humidity: 44% 35% 45% Surface Wind Direction: 010 360 360 Surface Wind Speed: 10 10 9 Transport Wind Direction: 010 010 360 Transport Wind Speed: 15 20 16 Mixing Height: 3800 4500 2500 Ventilation Index: 57 90 40 EXTENDED DISCUSSION: With a weak cut-off upper-level trough centered over northwestern California, the upper-level flow will turn weakly south-southwesterly on Saturday. That will further warm the air mass with valley highs near 90 degrees. Some mid-level moisture could circulate far enough northward for isolated thunderstorm development over the southern Cascades. The system over northern California will continue to weaken on Sunday, and Oregon will come under the influence of a more stable westerly flow aloft. The day will start out warmer than on Saturday, but increasing afternoon onshore flow should cap high temperatures near 90 degree. A weakening cold front is forecast to move into southern British Columbia, and extreme northwestern Washington, on Monday. That will further increase the onshore flow and could create favorable burning conditions Monday afternoon. The front is forecast to stall and weaken, well north of the region, on Tuesday, with the flow aloft warming and turning more southerly. South-southwesterly flow aloft is forecast for the middle of next week, which will warm temperatures into the middle and upper 80s and circulate enough moisture into the region for a chance of thunderstorms, mainly over the Cascades. It is possible that a weather system will turn the flow more southwesterly by Friday, which would push the thunderstorm threat eastward and possibly create a 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: 32256 bytes Desc: Silverton Hills Midday Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Mon Aug 22 08:39:42 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 22 Aug 2011 10:39:42 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Mon, Aug 22 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 Aug 22 11:49:34 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 22 Aug 2011 13:49:34 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Mon, Aug 22 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 Aug 23 08:29:04 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 23 Aug 2011 10:29:04 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Tue, Aug 23 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 Aug 23 11:49:43 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 23 Aug 2011 13:49:43 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Tue, Aug 23 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 Aug 24 08:55:44 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 24 Aug 2011 08:55:44 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 8:54 AM PDT WED AUG 24, 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 anchored over the south-central United States. The clockwise flow around it is directing a warm southwesterly flow aloft over Oregon. A weak disturbance, embedded in that flow, will turn the upper-level winds more southerly today. That will increase mid-level moisture and instability, with some thunderstorm development likely. The Salem sounding this morning showed several degrees of warming, compared to 24 hours ago, from the surface through 10,000 feet. Low-level winds were offshore, and satellite imagery this morning showed mostly clear skies over the northern two-thirds of Oregon. Transport winds are forecast to remain northerly or slightly offshore today, with increasingly southerly flow aloft. Mixing heights will be slow to rise due to warmer air aloft. Look for temperatures to be several degrees warmer than yesterday, with highs likely climbing into the low 90s. In addition, high dew-point temperatures will make it feel muggy. Daytime heating will combine with the increasing southerly flow aloft to spawn afternoon thunderstorm development. Storms will form first over southern Oregon and migrate northward, later this afternoon and evening, into northern Oregon. The best chance for thunderstorms will be over the Cascades, but some storms could make their way over the Willamette Valley. TODAY'S FORECAST: Sunny early; increasing clouds this afternoon with a chance of thunderstorms this evening and overnight. Warmer and muggy. Salem's high temperature today will be near 91 degrees (normal is 82). Relative humidity drops to near 60% around 11 a.m. and to near 37% by 5 p.m. Surface winds: N 5-10 mph. Transport winds: NNE 10-15 mph. Mixing height: Rises to 3000 feet by 2 p.m. and to 4000 feet by 5 p.m. Salem's sunset tonight: 8:03 p.m. THREE-HOURLY DATA: 11 a.m. 2 p.m. 5 p.m. 8 p.m. Temperature: 76 86 90 81 Relative Humidity: 60% 42% 37% 50% Surface Wind Direction: 360 360 360 330 Surface Wind Speed: 4 6 8 7 Transport Wind Direction: 020 010 010 340 Transport Wind Speed: 10 14 15 12 Mixing Height: 2000 3000 4000 1500 Ventilation Index: 20 42 60 18 EXTENDED DISCUSSION: The flow aloft is forecast to turn more southwesterly on Thursday, which will decrease the thunderstorm threat and cool temperatures a few degrees. Transport winds are forecast to remain north to northeasterly. Friday looks to be a repeat of today, with the flow aloft backing to more southerly and reintroducing a chance of thunderstorms. Burning opportunities are unlikely both days. The flow aloft is forecast to turn southwesterly again this weekend, which should bring a return of mostly sunny and warm weather. Long-range models are showing a possible burning opportunity for next Monday, as a system moving into southern British Columbia turns the flow aloft more westerly. 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 Wed Aug 24 11:47:56 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 24 Aug 2011 11:47:56 -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 WED AUG 24, 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 anchored over the south-central United States. The clockwise flow around it is directing a warm southwesterly flow aloft over Oregon. A weak disturbance, embedded in that flow, will turn the upper-level winds more southerly today and introduce the best chance of thunderstorms so far this summer into western Oregon Late-morning satellite imagery showed middle and high clouds advancing northward across the Willamette Valley. A more significant band of clouds was pushing northward across Douglas Lane Counties. Doppler radar showed some showers associated with these clouds but not any thunderstorms. Daytime heating will further destabilize the air mass over Oregon, so afternoon thunderstorm development is likely, bands of clouds continues to migrate northward. Most of the thunderstorms will be over the Cascades, but some storms are likely over the Willamette valley. Increasing clouds may act to limit afternoon heating, so the high temperature forecast was lowered slightly from this morning's forecast. Transport winds should remain northerly or slightly offshore this afternoon. A pibal is scheduled for 2 p.m. Winds will be highly variable, and possibly gusty, near showers and thunderstorms later this afternoon and evening. TODAY'S FORECAST: Warm and muggy. Increasing clouds with a chance of thunderstorms this afternoon through tonight. Salem's high temperature today will be near 90 degrees (normal is 82). Relative humidity drops to near 40% by 5 p.m. Surface winds: N 5-10 mph. Transport winds: NNE 10-15 mph. Mixing height: Rises to 3000 feet by 2 p.m. and to 4000 feet by 5 p.m. Salem's sunset tonight: 8:03 p.m. THREE-HOURLY DATA: 2 p.m. 5 p.m. 8 p.m. Temperature: 86 89 81 Relative Humidity: 42% 40% 50% Surface Wind Direction: 360 360 330 Surface Wind Speed: 6 8 7 Transport Wind Direction: 010 010 340 Transport Wind Speed: 14 15 12 Mixing Height: 3000 4000 1500 Ventilation Index: 42 60 18 EXTENDED DISCUSSION: The upper-level disturbance that will bring a threat of showers and thunderstorms overnight is forecast to move northeast of the region by Thursday morning. That should initiate a weak onshore surge and stabilize the air mass. Southwesterly flow aloft will decrease the thunderstorm threat and cool temperatures a few degrees. Afternoon transport winds are forecast to be northerly. Friday looks to be a repeat of today, with the flow aloft backing to more southerly and reintroducing a chance of thunderstorms. Burning opportunities are unlikely both days. The flow aloft is forecast to turn southwesterly again this weekend, which should stabilize the air mass and bring a return of mostly sunny and dry weather. Long-range models are still showing a possible burning opportunity for next Monday, as a system moving into southern British Columbia turns the flow aloft more westerly. 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 Thu Aug 25 08:45:15 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 25 Aug 2011 10:45:15 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Thu, Aug 25 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 Aug 25 12:34:50 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 25 Aug 2011 14:34:50 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Thu, Aug 25 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 Aug 26 08:56:57 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 26 Aug 2011 08:56:57 -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 AUG 26, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: There has been little change to the overall weather pattern. A large upper-level ridge of high pressure remains anchored over the south-central United States. The clockwise flow around it is continuing to direct a warm south to southwesterly flow aloft over Oregon. A small upper-level disturbance produced quite a lightning show early this morning. Thunderstorms rolled across the Willamette Valley, from SW to NE, before exiting over the northern Cascades. CoCoRaHS stations showed scattered rainfall totals, mostly less than one-tenth of an inch, across the southern valley and the east side of the north valley. The strongest storms were over the east side of the valley, with numerous rainfall reports of around one-tenth of an inch along the Cascade foothills. The greatest reported rainfall total was .26" at a site 6 miles ENE of Stayton, in Marion County. The upper-level disturbance that brought the thunderstorms early this morning has moved northeast of the region, and more stable conditions are expected today. Doppler radar was still showing some shower activity over the northern Oregon Cascades at mid-morning, but skies had mostly cleared over the Willamette Valley. Satellite imagery showed marine low clouds banked up along the coastal strip with some inland penetration into the coastal mountain gaps. Patchy low clouds are possible in the Willamette Valley this morning but should quickly give way to sunshine. The Salem sounding this morning showed northeasterly winds, and several degrees of warming compared to 24 hours ago, from about 1500 feet to 6000 feet. With quite warm air aloft, mixing heights will struggle to reach 3000 feet today, even with strong surface heating. The mid-morning surface map showed a thermal trough extending from southeastern Washington through southwestern Oregon with a weak north to northwest flow across the Willamette Valley. Surface and transport winds are forecast to be northerly today. TODAY'S FORECAST: Sunny and very warm. Salem's high temperature today will be near 91 degrees (normal is 81). Relative humidity drops to near 50% around 11 a.m. and to near 33% by 5 p.m. Surface winds: N 5-10 mph. Transport winds: NNE 10 mph this morning; N 12-15 mph this afternoon. Mixing height: Rises to 3000 feet by 4 p.m. and to 3200 feet by 5 p.m. Salem's sunset tonight: 8:00 p.m. THREE-HOURLY DATA: 11 a.m. 2 p.m. 5 p.m. 8 p.m. Temperature: 76 86 90 79 Relative Humidity: 52% 38% 33% 47% Surface Wind Direction: 360 360 360 330 Surface Wind Speed: 6 7 8 7 Transport Wind Direction: 010 360 360 350 Transport Wind Speed: 10 12 15 15 Mixing Height: 1500 2700 3200 1500 Ventilation Index: 15 32 48 23 EXTENDED DISCUSSION: The flow aloft is forecast to back to more southerly on Saturday and reintroducing a chance of thunderstorms, especially near and over the Cascades late in the day. High temperatures will only cool a couple of degrees. The upper-level flow is forecast to turn more southwesterly and stabilize on Sunday. Weak onshore flow may bring some marine clouds into the valley with temperatures cooling into the mid 80s (still above normal). Long-range models are showing a possible burning opportunity on Monday, as a system moving into southern British Columbia increasing both the southwesterly flow aloft and the onshore flow in the transport layer. 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 Aug 26 11:58:35 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 26 Aug 2011 11:58:35 -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 AUG 26, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. Propane flaming is not allowed. WEATHER DISCUSSION: There has been little change to the overall weather pattern. A large upper-level ridge of high pressure remains anchored over the south-central United States. The clockwise flow around it is continuing to direct a warm south to southwesterly flow aloft over Oregon. The upper-level disturbance that brought the thunderstorms to the Willamette Valley early this morning has moved northeast of the region, and more stable conditions are expected today. The late-morning surface map showed a thermal trough extending from north-central Oregon through southwestern Oregon with very weak northerly pressure-gradients across the Willamette Valley. Late-morning satellite imagery showed marine low clouds still banked up along most of the northern and central Oregon coast, but they were dissipating from the coastal mountain gaps. Patchy low clouds did make it into the extreme northern and southern Willamette Valley, but elsewhere sunny skies prevailed. With very warm air aloft, mixing heights will struggle to reach 3000 feet today, even with strong surface heating. TODAY'S FORECAST: Sunny and very warm. Salem's high temperature today will be near 90 degrees (normal is 81). Relative humidity drops to near 37% by 5 p.m. Surface winds: N 3-10 mph. Transport winds: N 10-15 mph. Mixing height: Rises to 3000 feet by 4 p.m. and to 3200 feet by 5 p.m. Salem's sunset tonight: 8:00 p.m. THREE-HOURLY DATA: 2 p.m. 5 p.m. 8 p.m. Temperature: 85 89 79 Relative Humidity: 42% 37% 47% Surface Wind Direction: 360 360 330 Surface Wind Speed: 7 8 7 Transport Wind Direction: 360 360 350 Transport Wind Speed: 10 12 12 Mixing Height: 2700 3200 1500 Ventilation Index: 27 38 18 EXTENDED DISCUSSION: The flow aloft is forecast to back to more southerly on Saturday; reintroducing a chance of thunderstorms, especially near and over the Cascades. High temperatures will only cool a couple of degrees. The upper-level flow is forecast to turn more southwesterly and stabilize on Sunday. Weak onshore flow may bring some marine clouds into the valley with temperatures cooling into the mid 80s (still above normal). Long-range models are showing a possible burning opportunity on Monday, as increasing southwesterly flow aloft pushes the surface thermal trough into Idaho and increases the onshore flow into western Oregon. 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: 31744 bytes Desc: Silverton Hills Midday Forecast.doc URL: From willamette-fcst at listsmart.osl.state.or.us Mon Aug 29 11:53:11 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 29 Aug 2011 13:53:11 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Mon, Aug 29 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 Aug 30 08:34:48 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 30 Aug 2011 10:34:48 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Tue, Aug 30 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 Aug 30 11:46:33 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 30 Aug 2011 13:46:33 -0500 Subject: [willamette-fcst] Field Burning Forecast for Silverton Hills - Tue, Aug 30 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 Aug 31 08:56:07 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 31 Aug 2011 08:56:07 -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 AUG 31, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is allowed from 11 a.m. until 2 p.m. with a 50 acre limit. Propane flaming is allowed from 11 a.m. until 5 p.m. WEATHER DISCUSSION: A cool but generally dry upper-level trough is over the Pacific Northwest this morning. An embedded disturbance rotated across northern Oregon overnight and deepened the marine layer over the Willamette Valley. The Salem sounding this morning showed an inversion at the top of the marine layer, at about 7000 feet, with some drying of the air mass below 5000 feet, compared to Tuesday morning. Winds were light southwesterly near the surface and veered to northwesterly up to 7000 feet. The freezing level was at just 10,000 feet, which is well below normal for the end of August. Mid-morning satellite imagery showed low clouds blanketing the Willamette Valley, but there were breaks in the clouds along the coast and over the coastal range. No rain was being reported in the valley, with temperatures in the mid to upper 50s. Since the lower layers of the air mass are not saturated, at most only patchy morning drizzle is possible. It appears as if conditions will become favorable for open burning today. With the air aloft being so cool, daytime heating will rapidly lift mixing heights above 3000 feet later this morning. Another upper-level disturbance is forecast to rotate across Washington and northern Oregon this afternoon, which will maintain the cool air aloft and likely allow mixing heights to rise to the top of the marine layer (around 7000 feet). Transport winds are forecast to slowly veer from WNW to NW this afternoon. Possible limiting factors for burning will be minor morning gradient-stacking, which should at least balance out this afternoon, and high surface humidity. There is also a slight chance of an afternoon shower. TODAY'S FORECAST: Mostly cloudy. Slight chance of morning drizzle and/or afternoon showers. Salem's high temperature today will be near 70 degrees (normal is 81). Relative humidity drops to near 50% from 2 p.m. through 5 p.m. Surface winds: W 3-6 mph this morning; NW 6-12 mph this afternoon. Transport winds: WNW 5-10 mph this morning; NW 10-15 mph this afternoon. Mixing height: Rises to 3000 feet by 11 a.m. and to near 7000 feet by 2 p.m. Salem's sunset tonight: 7:51 p.m. THREE-HOURLY DATA: 11 a.m. 2 p.m. 5 p.m. 8 p.m. Temperature: 63 67 68 63 Relative Humidity: 60% 50% 50% 60% Surface Wind Direction: 270 310 320 330 Surface Wind Speed: 4 6 10 10 Transport Wind Direction: 300 315 330 340 Transport Wind Speed: 6 12 15 20 Mixing Height: 3000 7000 6500 3000 Ventilation Index: 18 84 98 60 EXTENDED DISCUSSION: The upper-level trough is forecast to push east of the Cascades by Thursday morning with the flow aloft warming and turning more northerly Thursday afternoon. Transport winds will likely become mostly northerly, so the potential for open burning is poor. An upper-level ridge will build over the Pacific Northwest Friday through Sunday for much warmer conditions. Transport winds are forecast to become northerly on Friday and possibly offshore this weekend. Increasing southerly flow aloft may introduce a chance of thunderstorms into the region by Sunday. 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 Wed Aug 31 11:47:21 2011 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 31 Aug 2011 11:47:21 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 11:46 AM PDT WED AUG 31, 2011 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is allowed from now until 2 p.m. with a 50 acre limit. Propane flaming is allowed from now until 5 p.m. WEATHER DISCUSSION: A cool but generally dry upper-level trough is over the Pacific Northwest this morning. The Salem sounding this morning showed a deep marine layer extending from the surface up to almost 7000 feet. The lowest levels of the air mass have dried some since Tuesday, so cloud bases are up at nearly 6000 feet and are breaking up late this morning. Late-morning satellite imagery showed a band of low clouds, associated with another upper-level disturbance, rotating into northwestern Oregon. That system is helping to break up the marine clouds over the Willamette Valley but also adding to their vertical development. It is possible that some light showers could develop this afternoon. The outlook for open burning this afternoon remains favorable. There was still some minor gradient-stacking late this morning, which will need to get balanced out to ensure good smoke evacuation over the Cascades. That could happen by early this afternoon. Due to the very cool air aloft, mixing heights are likely already above 3000 feet. An 11 a.m. pibal showed light westerly winds up to 3800 feet, before the balloon was lost in the clouds. As mixing heights rapidly climb this afternoon, transport winds should increase in speed and slowly veer to northwesterly. TODAY'S FORECAST: Mostly cloudy. Slight chance of a shower. Salem's high temperature today will be near 70 degrees (normal is 81). Relative humidity drops to near 50% from 2 p.m. through 5 p.m. Surface winds: W 5 mph; becoming NW 6-12 mph this afternoon. Transport winds: W 5 mph; becoming NW 10-15 mph this afternoon. Mixing height: Rises to near 7000 feet by 2 p.m. Salem's sunset tonight: 7:51 p.m. THREE-HOURLY DATA: 2 p.m. 5 p.m. 8 p.m. Temperature: 67 68 63 Relative Humidity: 50% 50% 60% Surface Wind Direction: 310 320 330 Surface Wind Speed: 6 10 10 Transport Wind Direction: 315 330 340 Transport Wind Speed: 12 15 20 Mixing Height: 7000 6500 3000 Ventilation Index: 84 98 60 EXTENDED DISCUSSION: The upper-level trough is forecast to push into Idaho Thursday. The flow aloft will warm and turning more northerly, as an upper-level ridge begins to build over the region. Transport winds will likely turn northerly on Thursday and north-northeasterly on Friday, with high temperatures warming back into the low 80s by Friday. Open burning is highly unlikely both days. A weak upper-level ridge is forecast to move directly over Oregon on Saturday and begin pushing east of the state on Sunday. Temperatures will continue to warm with highs likely climbing into the low 90s by Sunday. Increasing southerly flow aloft may introduce a chance of thunderstorms into the region by Sunday afternoon. Increasing southwesterly flow aloft will bring some minor cooling on Monday and could initiate enough of an afternoon sea breeze to allow for limited open burning. Little chance to the overall weather pattern is forecast for the remainder of next week, with a continuation of warm and dry conditions. There could be enough onshore flow for limited burning opportunities, which will need to be monitored on a day-to-day basis. 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... 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