From willamette-fcst at listsmart.osl.state.or.us Thu Aug 1 08:48:45 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 1 Aug 2013 08:48:45 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast_doug.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT THURS. AUG. 1, 2013 BURN ADVISORY: Recommended burn times for agricultural burning are 1:00 p.m. to 6:00 p.m. Prep burning is not allowed. WEATHER DISCUSSION: The upper trough is centered right on the coastline today, with widespread low cloud cover over the area and areas of drizzle after the overnight marine surge. Showers are also persisting over the east slopes of the Cascade Range. Surface winds are light and variable, and surface pressure gradients are not favorable and not expected to improve significantly during the day. Mostly cloudy skies are expected for the area today with some areas of drizzle. The low cloud is not expected to burn off significantly this afternoon, so surface temperatures will be much cooler than yesterday. Scattered light showers this afternoon are possible. Transport winds will become mostly westerly later this morning at speeds of 5 to 15 mph. Surface winds will also likely be westerly this afternoon. Mixed layer depth will be limited with the lack of sunshine today. (Salem Airport data for Wednesday, July 31st: High 80?F; Rainfall .00") (Maximum Ventilation Index expected today: 30) TODAY'S FORECAST: Expect mostly cloudy skies with low-level winds becoming westerly. Salem's high temperature today will be in the low 70s. Relative humidity will be 50-60% late this afternoon. Surface winds: W 5-10 mph. Transport winds: W to NW at 5-15 mph. Maximum mixing height: 3000 ft. Sunset tonight: 8:38 p.m. EXTENDED DISCUSSION: Upper troughing is expected to persist over the area on Friday, with mostly cloudy and cool conditions continuing, and a chance of light showers. Some decrease in low clouds is possible late in the day. General onshore flow is expected, but the lack of favorable surface pressure gradients could limit the burning potential. On Saturday a gradual warming, drying trend should start, with the upper trough weakening, but low clouds early in the day are likely. 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. Doug Wesley ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Thu Aug 1 11:45:09 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 1 Aug 2013 11:45:09 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_doug.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT THURS. AUG. 1, 2013 BURN ADVISORY: Recommended burn times for agricultural burning are 1:00 p.m. to 6:00 p.m. Prep burning is not allowed. WEATHER DISCUSSION: The upper trough is centered right on the coastline today, with persistent widespread low cloud cover over the area and areas of drizzle. Showers are also persisting on the eastern side of the Cascade Range, as part of the trough energy is ejecting northeastward. Surface winds are light and variable, and surface pressure gradients are not favorable and not expected to improve significantly during the day. Mostly cloudy skies are expected for the area this afternoon with some areas of light drizzle. The low cloud is not expected to burn off, so surface temperatures are much cooler than yesterday. Scattered light showers this afternoon are possible. Transport winds will be mostly westerly at speeds of 5 to 15 mph. Surface winds will also likely become westerly this afternoon. Mixed layer depth will be limited to some degree with the lack of sunshine. (Salem Airport data for Wednesday, July 31st: High 80?F; Rainfall .00") (Maximum Ventilation Index expected today: 35) TODAY'S FORECAST: Expect mostly cloudy skies with low-level winds becoming westerly. Salem's high temperature today will be around 70. Relative humidity will be 50-60% late this afternoon. Surface winds: W 5-10 mph. Transport winds: W to NW at 5-15 mph. Maximum mixing height: 3500 ft. Sunset tonight: 8:38 p.m. EXTENDED DISCUSSION: Upper troughing is expected to persist over the area on Friday, with mostly cloudy and cool conditions continuing for much of the day, and a chance of light showers. Some decrease in low clouds is possible late in the day. General onshore flow is expected, but the lack of a favorable surface gradient pattern could limit the burning potential. On Saturday a gradual warming, drying trend should start, with the upper trough weakening, but low clouds early in the day over the area are likely. 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. Doug Wesley ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Fri Aug 2 08:37:45 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 2 Aug 2013 08:37:45 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast_doug.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT FRI. AUG. 2, 2013 BURN ADVISORY: Agricultural burning is not recommended today. Prep burning is not allowed. WEATHER DISCUSSION: Upper troughing continues over the area today, with widespread low cloud cover and areas of drizzle on the coast and west slopes of the Cascades. Surface winds are light and variable, and the surface pressure gradient pattern in place is not favorable and not expected to improve significantly during the day. Mostly cloudy skies are generally expected for the area through the morning, with partial clearing beginning late this morning in some areas of the valley. No areas of precipitation more than trace amounts are expected this morning. Surface temperatures will continue to be much cooler than average. Transport winds will become mostly northwesterly later today at speeds of 5 to 15 mph. Surface winds will also likely turn to northwesterly late this afternoon. Mixed layer depth should be improved somewhat over yesterday's depth. If clearing becomes extensive a favorable burn period may exist late this afternoon as the gradient pattern may become more favorable. (Salem Airport data for Wednesday, July 31st: High 68?F; Rainfall T) (Maximum Ventilation Index expected today: 35) TODAY'S FORECAST: Expect mostly cloudy skies through the morning with areas of drizzle over the west slopes of the Cascades, with some clearing on the south portion. Becoming partly cloudy this afternoon with low-level winds becoming northwesterly. Salem's high temperature today will be in the low to mid 70s. Relative humidity will drop to the 50-60% range this afternoon. Surface winds: NW 5-10 mph. Transport winds: NW 5-15 mph. Maximum mixing height: 3500 ft. Sunset tonight: 8:37 p.m. EXTENDED DISCUSSION: Upper troughing is expected to persist just west the area on Saturday, but slowly weaken. Cloudy conditions are expected in the morning, with clearing likely later in the day over the valley and warmer, drier conditions prevailing. Extensive cloudiness is not expected to persist past mid-morning over the west slopes of the Cascades either. Generally northerly transport flow is expected in the afternoon. On Sunday, the upper trough continues to weaken and is still located off the coast. Upper ridging strengthens east of the trough, over much of Oregon. Generally similar low-level conditions are expected locally, with less morning cloud coverage than Saturday. Mostly sunny skies can be expected for the afternoon. Early next week it appears likely that northerly low-level flow and dry conditions will be dominant. 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. Doug Wesley ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Fri Aug 2 11:47:09 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 2 Aug 2013 11:47:09 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_doug.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT FRI. AUG. 2, 2013 BURN ADVISORY: Agricultural burning is not recommended today. Prep burning is not allowed. WEATHER DISCUSSION: Upper troughing continues over the area today. Low cloud cover is beginning to slowly dissipate over the valley and adjacent west slopes of the Cascades, particularly on the south side. Surface winds are light and variable, and the surface pressure gradient pattern in place is mostly neutral with the potential of some improvement later. Skies will become partly cloudy early this afternoon over the area with more warming at the surface than yesterday. Transport winds will be northwesterly later today at speeds of 5 to 15 mph. Surface winds will also likely turn to northwesterly late this afternoon. Mixed layer depth should be improved somewhat over yesterday's depth. If clearing becomes extensive a favorable burn period may exist late this afternoon as the gradient pattern may become more favorable. We will monitor latest model guidance, PIBALs, surface and satellite data as conditions evolve. (Salem Airport data for Wednesday, July 31st: High 68?F; Rainfall T) (Maximum Ventilation Index expected today: 35) TODAY'S FORECAST: Becoming partly cloudy this afternoon with low-level winds becoming northwesterly. The gradient pattern should improve somewhat as the afternoon evolves. Salem's high temperature today will be in the low to mid 70s. Relative humidity will drop to the 50-60% range this afternoon. Surface winds: NW 5-10 mph. Transport winds: NW 5-15 mph. Maximum mixing height: 4000 ft. Sunset tonight: 8:37 p.m. EXTENDED DISCUSSION: Upper troughing is expected to persist just west the area on Saturday, but slowly weaken. Cloudy conditions are expected in the morning, with clearing likely later in the day over the valley and warmer, drier conditions prevailing. Extensive cloudiness is not expected to persist past mid-morning over the west slopes of the Cascades either. Generally northerly transport flow is expected in the afternoon. On Sunday, the upper trough continues to weaken and is still located off the coast. Upper ridging strengthens east of the trough, over much of Oregon. Generally similar low-level conditions are expected locally, with less morning cloud coverage than Saturday. Mostly sunny skies can be expected for the afternoon. Early next week it appears likely that northerly low-level flow and dry conditions will be dominant. 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. Doug Wesley ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Mon Aug 5 08:52:16 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 5 Aug 2013 08:52:16 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast_Pete.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT MON AUG 5, 2013 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. WEATHER DISCUSSION: A weak and mostly dry upper-level disturbance, moving across Washington, increased the onshore flow overnight across western Oregon. Marine low clouds blanket the coastline this morning, with some penetration into the coastal range gaps. However, skies have remained generally clear over the Willamette Valley. The upper-level disturbance is forecast to progress eastward, into northern Idaho, today. The combination of weak westerly flow aloft and onshore flow at the surface may turn transport winds enough northwesterly to allow for some burning today. However, a significant onshore surge is not expected this evening, as the upper-level ridge begins rebuilding over Oregon. Satellite imagery shows a plume of elevated wildfire smoke, about 100 miles wide, streaming from the fires over SW Oregon northeastward across central Oregon and into SE Washington. At least for today, the main elevated smoke plume should stay east of the Willamette Valley. TODAY'S FORECAST: Sunny and warm. Salem's high temperature today will be near 91 degrees (normal is 84). Relative humidity: Drops below 60% by 11 a.m. and to near 30% by 5 p.m. Surface winds: NNW 3-8 mph this morning; NW 5-10 mph this afternoon. Transport winds: NNW 5-8 mph this morning; NNW 10-12 mph this afternoon. Mixing height: Rising to 3000 feet by 2 p.m. and to near 4500 feet by 5 p.m. Salem's sunset tonight: 8:33 p.m. (Salem Airport data for Sunday, Aug. 4th: High 92?F; Rainfall .00") (Maximum Ventilation index expected today: 54) EXTENDED DISCUSSION: The upper-level ridge is forecast to rebuild over Oregon on Tuesday. That will suppress mixing heights and turn transport winds more northerly. Beginning Wednesday, and continuing through Friday, southerly flow aloft will likely transport elevated wildfire smoke across most of western Oregon. Transport winds should remain generally northerly. There will also be an increasing chance of thundershowers 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 (ft) times the transport wind speed (mph) divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Mon Aug 5 11:55:35 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 5 Aug 2013 11:55:35 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_Pete.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT MON AUG 5, 2013 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. WEATHER DISCUSSION: A dry and stable westerly flow aloft is bringing sunny skies to the interior of NW Oregon today. However, weak onshore flow is keeping marine low clouds banked up against the coastline. At the surface, a weak thermal trough extends from south-central Washington, along the crest of the northern Cascades, into SW Oregon. Late-morning pressure gradients are 3.6mb onshore from Newport to Salem but only 0.6mb onshore from Salem to Redmond. The lack of onshore pressure gradients east of Salem will be a limiting factor for burning this afternoon. Pressure gradients and transport winds will be monitored closely today (PIBALS begin at 1:00 p.m.) for the possibility of enough northwesterly flow to allow for some open burning. However, a significant onshore surge is not expected this evening, as an upper-level ridge begins rebuilding over Oregon. Smoke from the multiple wildfires in SW Oregon is being transported well up into the atmosphere, where southwesterly winds aloft (above 8000 feet) are transporting it northeastward across central Oregon and into SE Washington. That, elevated, smoke plume should stay east of the Willamette Valley today. TODAY'S FORECAST: Sunny and warm. Salem's high temperature today will be near 91 degrees (normal is 84). Relative humidity: Drops to near 30% by 5 p.m. Surface winds: NW 5-10 mph this afternoon. Transport winds: NNW 10-12 mph this afternoon. Mixing height: Rising to 3000 feet by 2 p.m. and to near 4500 feet by 5 p.m. Salem's sunset tonight: 8:33 p.m. (Salem Airport data for Sunday, Aug. 4th: High 92?F; Rainfall .00") (Maximum Ventilation index expected today: 54) EXTENDED DISCUSSION: The upper-level ridge is forecast to rebuild over Oregon on Tuesday. That will suppress mixing heights and turn transport winds more northerly. Beginning Wednesday, and continuing through Friday, southerly flow aloft will likely transport elevated wildfire smoke across most of western Oregon. Even though transport winds should remain generally northerly, settling and down-mixing of wildfire smoke may deteriorate air quality in the Willamette Valley. There will also be an increasing chance of thundershowers 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 (ft) times the transport wind speed (mph) divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Tue Aug 6 08:28:39 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 6 Aug 2013 08:28:39 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast_Pete.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT TUE AUG 6, 2013 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is allowed from 2 p.m. to 4 p.m. with a 50 acre limit. WEATHER DISCUSSION: An upper-level ridge is rebuilding over Oregon today. That will slightly suppress mixing heights, compared to Monday. Surface gradients are still weakly onshore from Newport to Salem but have turned offshore between Salem and Redmond. In response to the decrease in onshore flow, marine low clouds are confined mostly to the immediate coastline this morning. The morning sounding over Salem showed NE winds from just above the surface up through 2000 feet. With daytime heating, transport winds will likely back from northeasterly to more northerly this afternoon, but burning opportunities will be limited by the lack of onshore flow. Smoke from the multiple wildfires in SW Oregon is being transported well up into the atmosphere, where southwesterly winds aloft (above 8000 feet) have been transporting it northeastward across much of central Oregon and eastern Oregon. As the flow aloft turns more southerly today, that "elevated" smoke will begin migrating northward across western Oregon; likely spreading over the Willamette Valley by tonight. TODAY'S FORECAST: Sunny and very warm. Increasing wildfire smoke aloft late. Salem's high temperature today will be near 93 degrees (normal is 84). Relative humidity: Drops below 50% by 11 a.m. and below 30% by 2 p.m. Surface winds: N 2-6 mph this morning; N 5-10 mph this afternoon. Transport winds: NNE 4-8 mph this morning; N 8-12 mph this afternoon. Mixing height: Rising to 3000 feet by 2 p.m. and to near 4000 feet by 5 p.m. Salem's sunset tonight: 8:31 p.m. (Salem Airport data for Monday, Aug. 5th: High 93?F; Rainfall .00") (Maximum Ventilation index expected today: 54) EXTENDED DISCUSSION: An upper-level trough is forecast to move over northwestern California on Wednesday and stall there at least through Friday. South to southeasterly flow aloft will likely continue to transport "elevated" wildfire smoke across most of western Oregon. Even though transport winds should remain generally northerly, settling and down-mixing of wildfire smoke may deteriorate air quality in the Willamette Valley. There will also be an increasing chance of thundershowers, with temperatures cooling to near average. Burning opportunities will likely by very limited. Long-range computer models are consistent is showing a weather pattern change, around the middle of next week, to a more westerly flow aloft. That will end the thunderstorm threat and could create more substantial 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 (ft) times the transport wind speed (mph) divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Tue Aug 6 11:37:23 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 6 Aug 2013 11:37:23 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_Pete.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT TUE AUG 6, 2013 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is allowed from 2 p.m. to 4 p.m. with a 50 acre limit. WEATHER DISCUSSION: Afternoon mixing heights will be slightly lower today, compared to yesterday, due to a building ridge of high pressure over Oregon. Surface gradients are weakly onshore (2.8mb) from Newport to Salem but essentially flat (0.1mb onshore) from Salem and Redmond. Daytime heating should turn transport winds from northeasterly to northerly this afternoon, which is more favorable for prep burning. However, burning will be limited by the lack of onshore flow. Smoke from multiple wildfires in SW Oregon is lifting to well over 8000 feet, where southwesterly winds aloft have been transporting it across much of central and eastern Oregon. With the flow aloft turning more southerly, "elevated" wildfire smoke will begin migrating northward, across western Oregon, likely spreading over the Willamette Valley tonight. TODAY'S FORECAST: Sunny and very warm. Increasing "elevated" wildfire smoke late. Salem's high temperature today will be near 93 degrees (normal is 84). Relative humidity: Below 30%; dropping to near 20% by 5 p.m. Surface winds: N 5-10 mph this afternoon. Transport winds: N 8-12 mph this afternoon. Mixing height: Rising to 3000 feet by 2 p.m. and to near 4000 feet by 5 p.m. Salem's sunset tonight: 8:31 p.m. (Salem Airport data for Monday, Aug. 5th: High 93?F; Rainfall .00") (Maximum Ventilation index expected today: 54) EXTENDED DISCUSSION: An upper-level trough is forecast to move onto the northern California coast on Wednesday, stall there through Friday, then lift northward across western Oregon this weekend. South to southeasterly flow aloft will transport more wildfire smoke into the region along with increasing mid-level moisture and instability. That will bring a good chance of thundershowers into the valley, especially south, beginning Wednesday evening. These storms may initially be fairly dry, but the potential for wetting rains will increase through the week and into the weekend. Temperatures should cool back to near average. Long-range computer models continue to advertise a weather pattern change, around the middle of next week, to a dry and more stable westerly flow aloft. That will end the thunderstorm threat and could create more substantial open 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 (ft) times the transport wind speed (mph) divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Wed Aug 7 08:44:02 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 7 Aug 2013 08:44:02 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast_doug.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT WED. AUG. 7, 2013 BURN ADVISORY: Agricultural burning is not recommended today. Prep burning is not allowed. WEATHER DISCUSSION: An upper-level closed low is spinning off the northern CA coastline today, and the associated cloudiness and even some light showers are spreading northward into the valley. Deep southerly to southeasterly flow aloft is beginning to predominate as the closed low slowly moves northeast. Surface winds are light and variable, and the surface pressure gradient pattern in place is weakly favorable but not expected to improve significantly during the day. Mostly cloudy skies are generally expected for the area through the day, with some light shower activity reaching the ground over portions of the south. Surface temperatures will be about 10 degrees cooler than yesterday due to the cloud cover. Transport winds will be mostly north-northeasterly later today at speeds of 5 to 15 mph. Surface winds will also likely become NNE late this afternoon. Mixed layer depth should be decreased somewhat over yesterday's depth. Hazy skies are also likely to continue today as wildfire smoke continues to be transported north from far southwest OR. (Salem Airport data for Tues., August 6: High 95?F; Rainfall 0) (Maximum Ventilation Index expected today: 30) TODAY'S FORECAST: Expect mostly cloudy skies through day and cooler with low-level winds becoming NNE but remaining weak. Some light showers will be scattered though the area, most numerous over the south side. Winds could get erratic this afternoon in the vicinity of showers. Salem's high temperature today will be in the low to mid 80s. Relative humidity will drop to the 35-40% range this afternoon. Surface winds: NNE 5-10 mph. Transport winds: NNE 5-15 mph. Maximum mixing height: 3500 ft. Sunset tonight: 8:30 p.m. EXTENDED DISCUSSION: Upper troughing is expected to continue on Thursday, with partly to mostly cloudy skies and the continued chance of light showers. Weak transport flows are also likely to continue. Generally northerly transport flow is expected in the afternoon. On Friday, general persistence is expected as the upper trough is likely to be centered just south of the valley. Shower activity will likely increase, and an onshore wind pattern is not expected. The trough is very slow to move to the north and on Saturday no significant changes are expected 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. Doug Wesley ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Wed Aug 7 11:48:54 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 7 Aug 2013 11:48:54 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_doug.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT WED. AUG. 7, 2013 BURN ADVISORY: Agricultural burning is not recommended today. Prep burning is not allowed. WEATHER DISCUSSION: An upper-level closed low is spinning off the northern CA coastline today, and the associated cloudiness and even some light showers are spreading northward into the south end of the valley. Deep southerly to southeasterly flow aloft (above 10000 feet AGL) is developing as the closed low slowly moves northeast. Surface winds are light and variable, and the surface pressure gradient pattern in place is weakly favorable but not expected to improve significantly during the afternoon. At 11:00 a.m. the gradient was 3.6 mb Newport-Salem and 1.6 mb Salem-Redmond. Mostly cloudy skies are generally expected for the area through the rest of the day, with some light shower activity reaching the ground over south portions. Surface temperatures will be about 10 degrees cooler than highs yesterday due to the cloud cover. Transport winds will be mostly north-northeasterly later today at speeds of 5 to 15 mph. Any changeover to NNW would be this evening. Surface winds will also likely become N late this afternoon, with a possible switch to NNW after 6pm. Mixed layer depth will be decreased somewhat over yesterday's depth. Hazy skies are also likely to continue today as some wildfire smoke continues to be transported north from far southwest OR. (Salem Airport data for Tues., August 6: High 95?F; Rainfall 0) (Maximum Ventilation Index expected today: 30) TODAY'S FORECAST: Expect mostly cloudy skies this afternoon with low-level winds becoming generally N but remaining weak. Some light showers will be scattered though the area, most numerous over the south side. Winds could get erratic this afternoon in the vicinity of showers. Salem's high temperature today will be in the low to mid 80s. Relative humidity will drop to the 35-40% range this afternoon. Surface winds: N 5-10 mph. Transport winds: N 5-15 mph. Maximum mixing height: 3500 ft. Sunset tonight: 8:30 p.m. EXTENDED DISCUSSION: Upper troughing is expected to continue on Thursday, with partly to mostly cloudy skies and the continued chance of light showers. N transport flows are also likely to continue. On Friday, general persistence is expected as the upper trough is likely to be centered just south of the valley and cloud cover will be significant. Shower activity will likely increase, and an onshore wind pattern is not expected. The trough is very slow to move to the north and on Saturday no significant changes are expected 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. Doug Wesley ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Thu Aug 8 08:44:00 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 8 Aug 2013 08:44:00 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast_doug.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT THURS. AUG. 8, 2013 BURN ADVISORY: Agricultural burning is not recommended today. Prep burning is not allowed. WEATHER DISCUSSION: An upper-level closed low continues to spin just to our southwest off the coast today. Deep southeasterly flow aloft is in place over western OR as the closed low slowly moves northeast. Surface winds are light and mostly southerly, and the surface pressure gradient pattern in place is unfavorable. Low clouds currently cover most of the southern portion of the valley after the marine push from the west late yesterday. Low clouds will mostly dissipate later this morning. However, partly to mostly cloudy skies will develop later and are generally expected through the afternoon, as moisture aloft is widespread out ahead of the upper closed low to the southwest. Some shower and thunderstorm activity is a possibility in the south valley and likely for SW/south central OR late in the day. Surface temperatures will be a bit cooler than yesterday, mixing heights will remain moderate, and transport winds will be mostly northerly later today at speeds of 5 to 15 mph. Surface winds will also likely become N late this afternoon. (Salem Airport data for Wed., August 7: High 83?F; Rainfall 0) (Maximum Ventilation Index expected today: 30) TODAY'S FORECAST: Expect partly to mostly cloudy skies through day. Cooler than average temperatures are expected, with low-level winds becoming mostly N but remaining weak. Some light showers are possible late today on the south side. Winds could get erratic this afternoon in the vicinity of these showers. Salem's high temperature today will be around 80. Relative humidity will drop to the 40-50% range this afternoon. Surface winds: N 5-10 mph. Transport winds: N 5-15 mph. Maximum mixing height: 2500 ft. Sunset tonight: 8:28 p.m. EXTENDED DISCUSSION: The upper trough gradually approaches western OR on Friday, with partly to mostly cloudy skies expected to continue in the valley with a chance of light showers. Again, any significant rain will likely be confined to the southern portions through much of the day. Weak transport flows are also likely to continue, but there is a possibility of some onshore gradients late in the day. Evening showers may spread through the valley. On Saturday, even more cloudiness and showery weather is expected as the upper trough likely moves into western OR. Shower activity will likely increase over the valley late in the day and mixing heights will be low. A drying trend is currently advertised on model guidance beginning Sunday, but cloudy conditions are expected in the morning. 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. Doug Wesley ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Thu Aug 8 11:48:03 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 8 Aug 2013 11:48:03 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_doug.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT THURS. AUG. 8, 2013 BURN ADVISORY: Agricultural burning is not recommended today. Prep burning is not allowed. WEATHER DISCUSSION: An upper-level closed low continues to spin just to our southwest off the coast today. Deep southeasterly flow aloft is in place over western OR as the closed low slowly edges northeast. Surface winds are light and variable, and the surface pressure gradient pattern in place is unfavorable. Low clouds have now cleared over much of the valley and Silverton Hills. Skies will become partly cloudy this afternoon, as moisture aloft has increased out ahead of the upper closed low to the southwest. Isolated shower activity is a possibility in the south valley and southern Cascades, and more widespread for far SW and south central OR late in the day. Surface temperatures will be a bit cooler than yesterday, mixing heights will remain moderate, and transport winds will be mostly northerly later today at speeds of 5 to 15 mph. Surface winds will also become N-NE late this afternoon. (Salem Airport data for Wed., August 7: High 83?F; Rainfall 0) (Maximum Ventilation Index expected today: 30) TODAY'S FORECAST: Expect skies to become partly cloudy this afternoon. Cooler than average temperatures are expected, with low-level winds and transport winds becoming N to NE but remaining weak. Some light showers are possible late today for the southern portion of the valley and hills. Winds could get erratic late this evening in the vicinity of these showers. A favorable gradient pattern is not likely. Salem's high temperature today will be around 80. Relative humidity will drop to the 30-40% range this afternoon. Surface winds: N to NE 5-10 mph. Transport winds: N to NE 5-15 mph. Maximum mixing height: 2500 ft. Sunset tonight: 8:28 p.m. EXTENDED DISCUSSION: The upper trough gradually approaches western OR on Friday, with partly to mostly cloudy skies expected to continue in the region with a chance of light showers. Again, any significant rain will probably be confined to the southern portions through much of the day. Weak transport flows are also likely to continue, but there is a possibility of some onshore gradients developing late in the day. Also, more widespread showers in the valley are possible during the evening hours. On Saturday, more cloudiness and increased shower activity are expected as the upper trough moves into western OR. Showers will be most likely late in the day and mixing heights will be relatively low. A drying trend is currently advertised on model guidance beginning Sunday, but cloudy conditions are expected in the region for at least the morning period. 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. Doug Wesley ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Fri Aug 9 08:56:41 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 9 Aug 2013 08:56:41 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast_doug.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT FRI. AUG. 9, 2013 BURN ADVISORY: Agricultural burning is not recommended today. Prep burning is not allowed. WEATHER DISCUSSION: An upper-level closed low continues to spin just to our southwest off the coast today. Deep easterly flow aloft is in place over western OR as the closed low slowly edges to the northeast. Surface winds are light and variable, and the surface pressure gradient pattern is weakly favorable at the moment. Cloudy conditions are widespread with light showers moving westward over the southern portions of the Silverton Hills. Deep moisture will dominate the weather today with scattered shower activity likely to continue, with possible thunderstorms late in the day and this evening. Surface temperatures will be a bit cooler than yesterday, mixing heights will be lower as a result, and transport winds will be mostly northerly later today at speeds of 5 to 15 mph. Surface winds will also become N-NE late this afternoon. (Salem Airport data for Thurs., August 8: High 85?F; Rainfall 0) (Maximum Ventilation Index expected today: 25) TODAY'S FORECAST: Expect skies to remain mostly cloudy this afternoon with scattered showers and a chance of thunderstorms, some of which could produce significant rain especially at higher elevations. Cooler than average temperatures are expected, with low-level winds and transport winds becoming N to NE but remaining weak. Winds could get erratic late today in the vicinity of thunderstorms. Weakly favorable gradients are expected to continue. Salem's high temperature today will be around 80. Relative humidity will drop to the 40-45% range this afternoon. Surface winds: N to NE 5-10 mph. Transport winds: N to NE 5-15 mph. Maximum mixing height: 2500 ft. Sunset tonight: 8:27 p.m. EXTENDED DISCUSSION: The center of the upper trough gradually will move northward on Saturday, and mostly cloudy skies are expected to continue in the region with scattered showers. Rainfall tonight and Saturday will likely reduce the potential for burning in many areas. Weak transport flows are also likely to continue, but there is a chance of some onshore gradients developing late in the day on Saturday. On Sunday, the upper low is likely to progress further northward into western WA. Expect extensive cloudiness and remnant shower activity in the morning over the Silverton Hills, but a drying trend is probable in the afternoon with some possible clearing skies. Low clouds could persist through the day in the valley. Cool low-level conditions will continue. The current outlook for early next week is generally more favorable for some onshore flow as the upper flow trends towards southwesterly. 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. Doug Wesley ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Fri Aug 9 11:48:14 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 9 Aug 2013 11:48:14 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_doug.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT FRI. AUG. 9, 2013 BURN ADVISORY: Agricultural burning is not recommended today. Prep burning is not allowed. WEATHER DISCUSSION: An upper-level closed low continues to spin just to our southwest off the coast today, slowly edging northeastward. Deep easterly flow aloft is in place over western OR as the closed low slowly edges to the northeast. Surface winds are continuing light and variable, and the surface pressure gradient pattern is weakly favorable as of 11:00 a.m. Partly to mostly cloudy conditions are in place. Cloud cover will increase this afternoon with scattered shower activity moving into the region from the east by early evening, accompanied by possible thunderstorms. Surface temperatures will be a bit cooler than yesterday, mixing heights will be moderate, and transport winds will be mostly northerly later today at speeds of 5 to 15 mph. Surface winds will also become N-NE this afternoon and then NNW this evening. (Salem Airport data for Thurs., August 8: High 85?F; Rainfall 0) (Maximum Ventilation Index expected today: 30) TODAY'S FORECAST: Expect skies to become mostly cloudy late this afternoon with scattered showers and a chance of thunderstorms by evening, some of which could produce significant rain tonight, especially at higher elevations. Low-level winds and transport winds becoming N to NE but remaining weak. Winds could get erratic this evening in the vicinity of thunderstorms. Weakly favorable gradients are expected to continue. NNW surface flow is likely this evening. Salem's high temperature today will be around 80. Relative humidity will drop to the 40-45% range this afternoon. Surface winds: N to NE 5-10 mph becoming NNW 5-15 mph this evening. Transport winds: N 5-15 mph. Maximum mixing height: 2500-3000 ft. Sunset tonight: 8:27 p.m. EXTENDED DISCUSSION: The center of the upper trough gradually will move northward on Saturday, and mostly cloudy skies are expected to continue over the region with scattered showers late in the day. Rainfall tonight and late Saturday will likely reduce the potential for burning in many areas. Weak transport flows are also likely to continue, but there is again a chance of some onshore gradients developing late in the day on Saturday. On Sunday, the upper low is likely to progress further northward into western WA. Expect extensive cloudiness and remnant shower activity in the morning over the Silverton Hills, but a drying trend is probable in the afternoon with some clearing skies possible. Low clouds could persist through the day in the valley. Cool low-level conditions will continue. The current outlook for early next week is generally more favorable for some onshore flow as the upper flow trends towards southwesterly, especially on Tuesday. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Doug Wesley ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Mon Aug 12 08:52:06 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 12 Aug 2013 08:52:06 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast_Pete.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT MON AUG 12, 2013 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. WEATHER DISCUSSION: The upper-level trough that brought scattered thunderstorms to northwestern Oregon over the weekend has moved north of the region and is centered just off the northern Washington coast this morning. In its wake, strong onshore flow has stabilized the air mass and forced marine low clouds inland across the Willamette Valley. The morning sounding over Salem this morning was very similar to Sunday morning, with a saturated marine layer extending up to about 4000 feet. Winds are light in the marine layer, with southwesterly winds above it. Pressure gradients are onshore and evenly "stacked" this morning from Newport to Redmond. However, skies are clear east of the Cascade crest, so central Oregon will warm faster than western Oregon this morning; initially yielding unfavorable pressure gradients for burning. The marine clouds should begin breaking up early this afternoon. As the valley warms, pressure gradients will likely become favorable for open burning. Low-level winds should remain fairly light and turn northwesterly. Winds will stay southwesterly near the mixing height, which should rise to near 5000 feet later this afternoon. If skies clear early this afternoon, as expected, the prospects are good for open burning later in the afternoon. TODAY'S FORECAST: Morning clouds; becoming mostly sunny this afternoon. Salem's high temperature today will be near 80 degrees (normal is 83). Relative humidity: Drops to 50% by 11 a.m. and to near 40% by 5 p.m. Surface winds: SW 2-6 mph this morning; NW 4-7 mph this afternoon. Transport winds: W 5 mph this morning; W 6-10 mph this afternoon. Mixing height: Rising to 4000 feet by 2 p.m. and to near 5000 feet by 5 p.m. Salem's sunset tonight: 8:22 p.m. (Salem Airport data for Sunday, Aug. 11th: High 77?F; Rainfall .00") (Maximum Ventilation index expected today: 50) EXTENDED DISCUSSION: A dry and stable southwesterly flow aloft is forecast on Tuesday, with morning clouds giving way more quickly to sunny skies. Temperatures should warm into the mid 80s with transport winds turning mostly northerly. Another mostly sunny and warm day is expected on Wednesday, but an approaching upper-level trough will increase the southwesterly flow aloft, which could lead to very favorable open burning conditions Wednesday afternoon. A weak cold front is expected to come onshore Wednesday night, with more clouds and cooler temperatures on Thursday. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer (ft) times the transport wind speed (mph) divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Mon Aug 12 11:54:10 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 12 Aug 2013 11:54:10 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_Pete.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT MON AUG 12, 2013 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. WEATHER DISCUSSION: In the wake of an upper-level trough exiting to the north of the state, onshore flow has stabilized the air mass and forced a deep marine layer into western Oregon. Winds are light through the marine layer, with southwesterly flow above it. With sunshine heating central Oregon, late this morning, and low clouds retarding heating west of the Cascade crest, pressure gradients have turned slightly unfavorable for burning. Late-morning satellite imagery shows the low clouds beginning to break up over the northern Willamette Valley but still solidly covering the central and southern valley. Skies should begin clearing over the Silverton Hills area by 2 p.m. As the valley warms, onshore pressure gradients will become increasingly more favorable for open burning. Low-level winds should remain fairly light and turn northwesterly. Winds will stay southwesterly near the mixing height, which should rise to near 5000 feet by late this afternoon. PIBALS are scheduled to begin at 1:00 p.m. If skies clear soon enough, then the prospects are good for open burning later this afternoon. TODAY'S FORECAST: Morning clouds; becoming mostly sunny this afternoon. Salem's high temperature today will be near 80 degrees (normal is 83). Relative humidity: Drops to near 40% by 5 p.m. Surface winds: Becoming NW 4-7 mph this afternoon. Transport winds: W 6-10 mph this afternoon. Mixing height: Rising to 4000 feet by 2 p.m. and to near 5000 feet by 5 p.m. Salem's sunset tonight: 8:22 p.m. (Salem Airport data for Sunday, Aug. 11th: High 77?F; Rainfall .00") (Maximum Ventilation index expected today: 50) EXTENDED DISCUSSION: A dry and stable southwesterly flow aloft is forecast on Tuesday, with morning clouds giving way more quickly to sunny skies. Temperatures should warm into the mid 80s with transport winds turning mostly northerly. Another mostly sunny and warm day is expected on Wednesday, but an approaching upper-level trough will increase the southwesterly flow aloft, which could lead to very favorable open burning conditions Wednesday afternoon. A weak cold front is expected to come onshore Wednesday night, with more clouds and cooler temperatures on Thursday. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer (ft) times the transport wind speed (mph) divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Tue Aug 13 08:53:27 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 13 Aug 2013 08:53:27 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_Pete.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT TUE AUG 13, 2013 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is allowed from 1 p.m. to 3 p.m. with a 50 acre limit. WEATHER DISCUSSION: A dry and stable southwesterly flow aloft has weakened the onshore flow today. Pressure gradients are evenly stacked this morning and have relaxed to just over 2 mb onshore from Newport to Redmond. Only patchy marine low clouds have formed in the valley this morning and should give way to sunny skies by midday. The morning sounding over Salem showing several degrees of warming, above 4000 feet, compared to Monday morning. That will cap maximum mixing heights near 4000 feet, even with surface temperatures warming into the mid 80s this afternoon. NNE transport winds this morning should turn northerly this afternoon. Winds may turn to the NNW late but not likely enough to allow for significant burning. TODAY'S FORECAST: Morning clouds; becoming mostly sunny this afternoon. Salem's high temperature today will be near 85 degrees (normal is 83). Relative humidity: Drops to 50% by noon and to near 30% by 5 p.m. Surface winds: NNE 2-6 mph this morning; N 5-10 mph this afternoon. Transport winds: NNE 5 mph this morning; N 6-12 mph this afternoon. Mixing height: Rising to 3000 feet by 1 p.m. and to near 4000 feet by 5 p.m. Salem's sunset tonight: 8:21 p.m. (Salem Airport data for Monday, Aug. 12th: High 78?F; Rainfall .00") (Maximum Ventilation Index expected today: 40) EXTENDED DISCUSSION: Increasing high clouds are expected on Wednesday, as an approaching upper-level trough increases the southwesterly flow aloft. That will likely lead to very favorable open burning conditions Wednesday afternoon, as transport winds turn southwesterly. A weak cold front is forecast to stall as it moves onshore Wednesday night. Some drizzle or light rain is possible along the coast, with minimal inland penetration. More clouds and onshore flow will cool temperatures a few degrees on Thursday, with some burning possible. Another weak front is forecast to approach the coastline on Friday, which could also create favorable burning conditinos. 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 (ft) times the transport wind speed (mph) divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Tue Aug 13 11:33:09 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 13 Aug 2013 11:33:09 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_Pete.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT TUE AUG 13, 2013 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is allowed from 1 p.m. to 3 p.m. with a 50 acre limit. WEATHER DISCUSSION: A dry and stable southwesterly flow aloft has weakened the onshore flow today. Patchy marine clouds quickly gave way to sunshine this morning across the Willamette Valley, with late-morning temperatures running about 5 degrees warmer than 24 hours ago. The air aloft is also warmer, so afternoon mixing heights should not exceed 4000 feet, even with high temperatures expected to climb into the mid 80s. Onshore pressure gradients were evenly stacked late this morning (Newport to Salem was 1.5 mb and Salem to Redmond was 1.3 mb, as of 11 a.m.) and should turn slightly favorable for burning this afternoon. However, prevailing northerly transport winds will not likely allow for significant burning. PIBALS will begin at 2 p.m. to monitor for any shift or increase in transport winds that would allow for open burning. TODAY'S FORECAST: Sunny and warmer this afternoon. Salem's high temperature today will be near 85 degrees (normal is 83). Relative humidity: Drops to near 30% by 5 p.m. Surface winds: N 5-10 mph this afternoon. Transport winds: N 6-12 mph this afternoon. Mixing height: Rising to 3000 feet by 1 p.m. and to near 4000 feet by 5 p.m. Salem's sunset tonight: 8:21 p.m. (Salem Airport data for Monday, Aug. 12th: High 78?F; Rainfall .00") (Maximum Ventilation Index expected today: 40) EXTENDED DISCUSSION: Increasing high clouds are expected on Wednesday, as an approaching upper-level trough increases the southwesterly flow aloft. That will likely lead to very favorable open burning conditions fairly early Wednesday afternoon. This could be a significant burning opportunity, with southwesterly transport winds and mixing heights rising to near or above 5000 feet. A weak cold front is forecast to stall as it moves onshore Wednesday night. Some drizzle or light rain is possible along the coast, but little or no precipitation is expected in the Willamette Valley. More clouds and onshore flow will likely bring slight cooling on Thursday, but conditions may remain favorable for additional burning Thursday afternoon. A stronger front is forecast to move onshore Friday. If the timing is right, it could create another significant burning opportunity, Friday afternoon, with southwesterly transport winds and mixing heights rising to near or above 5000 feet. 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 (ft) times the transport wind speed (mph) divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Wed Aug 14 08:56:28 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 14 Aug 2013 08:56:28 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast_Pete.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT WED AUG 14, 2013 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. WEATHER DISCUSSION: Middle and high clouds are on the increase across western Oregon this morning, in response to an approaching Pacific weather system. The offshore storm has more of an early autumn-like appearance on satellite imagery but is forecast to weaken as it very slowly moves onshore and stalls along the coastline later this afternoon and evening. That should produce a prolonged period of favorable open burning conditions, beginning early this afternoon, as southerly low-level winds veer to the southwest and cooling aloft combines with continued warm surface temperatures to lift mixing heights above 3000 feet. Onshore pressure gradients are already favorably stacked this morning to promote sustained lifting of smoke, so the limiting factors today will be mixing heights and wind direction. PIBALS are scheduled to begin early today, at 11 a.m., since favorable burning conditions may begin in the early afternoon. Rain is likely along the coast later today but should stay west of the Valley until tonight. TODAY'S FORECAST: Increasing clouds. Chance of light rain late. Salem's high temperature today will be near 85 degrees (normal is 83). Relative humidity: Drops to 50% by noon and to near 35% by 5 p.m. Surface winds: S 2-7 mph this morning; SW 5-10 mph this afternoon. Transport winds: SSW 10 mph this morning; SW 15 mph this afternoon. Mixing height: Rising to 3000 feet by 1 p.m. and to near 5000 feet by 5 p.m. Salem's sunset tonight: 8:19 p.m. (Salem Airport data for Tuesday, Aug. 13th: High 86?F; Rainfall .00") (Maximum Ventilation Index expected today: 75) EXTENDED DISCUSSION: The weather system will continue to weaken as it moves inland tonight and Thursday, with a chance of light rain in the Willamette Valley. More clouds and onshore flow will likely bring several degrees of cooling on Thursday, but conditions may remain favorable for additional burning, if fields are able to stay dry. Another weather system is forecast to move onshore Friday. If the timing is right and fields are dry enough, it could create another 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 (ft) times the transport wind speed (mph) 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_Pete.doc Type: application/msword Size: 31744 bytes Desc: Silverton Hills AM Forecast_Pete.doc URL: From willamette-fcst at listsmart.osl.state.or.us Wed Aug 14 11:51:46 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 14 Aug 2013 11:51:46 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_Pete.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT WED AUG 14, 2013 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. WEATHER DISCUSSION: Middle and high clouds continue to stream over Oregon ahead of an autumn-like cold front that stretches from southwestern British Columbia to about 200 miles west of the Oregon coast. The cold front is forecast to weaken as it very slowly approaches the Oregon coast this afternoon and moves onshore this evening. South-southwesterly flow aloft is also transporting "elevated" smoke over the region from wildfires in SW Oregon and northern California. As of late this morning, radar showed rainfall just off the Washington and northern Oregon coast. A few sprinkles had progressed as far south and east as Astoria, on the northern Oregon coast. Ahead of the storm, temperatures in the Willamette Valley were generally in the mid to upper 70s, which is about 5-8 degrees warmer than 24 hours ago). The air aloft has also warmed several degrees since yesterday, so mixing heights will not reach 3000 feet until surface temperatures climb into the low 80s this afternoon. Onshore pressure gradients are already favorable to promote sustained lifting of smoke, so the limiting factors today will be mixing heights and wind direction. An 11 a.m. PIBAL showed mostly south to southwesterly winds from the surface up to 4000 feet, with mixing heights estimated near 2000 feet. Both were in-line with computer model guidance. The forecast is for the winds to slowly turn more southwesterly this afternoon, as mixing heights climb above 3000 feet. That will likely create favorable open burning conditions by mid-afternoon, if not sooner. Hourly PIBALS are scheduled to closely monitor this predicted shift in transport winds. Some rain is likely to move onshore this afternoon but should remain west of the Silverton Hills. It is highly questionable how much rain will eventually make it into the northern Willamette Valley tonight and Thursday, as the frontal system stalls and falls apart. Some model guidance is suggesting up to one-quarter of an inch of rain may fall in the Salem area tonight through Thursday, but that looks to be overdone. A trace to a few hundredths of an inch is a more likely target. TODAY'S FORECAST: Considerable middle and high clouds. Chance of light rain late. Salem's high temperature today will be near 85 degrees (normal is 83). Relative humidity: Drops to near 35% by 5 p.m. Surface winds: SSW 5-10 mph; Becoming SW 5-10 mph this afternoon. Transport winds: S 15 mph; Becoming SW 15 mph this afternoon. Mixing height: Rising to 3000 feet about 1 p.m. and to 4-5000 feet by 5 p.m. Salem's sunset tonight: 8:19 p.m. (Salem Airport data for Tuesday, Aug. 13th: High 86?F; Rainfall .00") (Maximum Ventilation Index expected today: 75) EXTENDED DISCUSSION: A decaying cold front will bring mostly cloudy skies, cooler temperatures, and perhaps some light rain to the Willamette Valley tonight and Thursday. Transport wind directions are forecast to be favorable for burning Thursday afternoon, but conditions may be too damp. Another weather system is forecast to weaken as it moves onshore Friday. If the timing is right and conditions remain dry enough, it could create another burning opportunity Friday 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 (ft) times the transport wind speed (mph) divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Thu Aug 15 08:45:07 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 15 Aug 2013 08:45:07 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast_doug.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT THURS AUG 15, 2013 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. WEATHER DISCUSSION: Middle and high clouds continue to stream over northwestern Oregon ahead of an upper trough off the Oregon coast. A few light showers are on the west side of the valley and over coastal areas this morning, but these are not expected to make much progress inland today as the trough is not progressive. The showery areas are moving to the north-northeast. Surface heating will be limited today compared to yesterday, due primarily to the cloud cover. Mixing heights will likely not reach the deep levels we saw yesterday, but 3000 feet should be reached once we get surface temperatures up into the middle 70s this afternoon. Like yesterday, a favorable wind profile is in place with mostly southwesterly flow through the day, with potentially more toward westerly late in the day. Currently surface pressure gradients are very weak. Gradient stacking against easterly transport could be an issue this afternoon as the Cascades should heat faster than the valley. The gradient pattern will be monitored closely. If stacking does not occur we should get some favorable open burning conditions by mid-afternoon. Since rain did not occur in the Silverton Hills overnight, wet fields should not be a factor. TODAY'S FORECAST: Mostly cloudy this morning with partial clearing this afternoon and cooler. A few light showers are possible on the western side of the valley through the day. Salem's high temperature today will be around 80. Relative humidity: Drops to near 40% by 4 p.m. Surface winds: S 5-10 mph; becoming SW 5-10 mph this afternoon. Transport winds: SW 10-15 mph this afternoon. Mixing height: Rising to 3500 feet late this afternoon. Salem's sunset tonight: 8:18 p.m. (Salem Airport data for Wednesday, Aug. 14th: High 87?F; Rainfall .00") (Maximum Ventilation Index expected today: 40) EXTENDED DISCUSSION: The upper trough will remain off the coast and deepen on Friday. Southwesterly transport wind directions are forecast to continue for the afternoon under partly cloudy skies, with a chance of showers late. Potential burning conditions should continue in the afternoon. More of an onshore pattern is forecast for Saturday as surface temperatures continue near to just below the seasonal average. Morning low clouds are a possibility. No major changes are forecast for Sunday but weaker flow aloft is likely and low clouds are again possible early in the 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 (ft) times the transport wind speed (mph) 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. Doug Wesley ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Thu Aug 15 11:50:14 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 15 Aug 2013 11:50:14 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_doug.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT THURS AUG 15, 2013 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. WEATHER DISCUSSION: Cloudy skies continue to dominate over the Silverton Hills and Willamette Valley as of noon, ahead of the upper trough off the Oregon coast. Light showers continue to be confined to the west side of the valley and over coastal areas this morning; these are still not expected to move eastward today as the trough is not progressive. Surface heating is more limited today compared to yesterday, due primarily to the cloud cover. Mixing heights will likely not reach the deep levels we saw yesterday, but 3000+ feet should be reached by early afternoon. Noon PIBAL data will be examined closely for more specific timing of these favorable burning conditions. Like yesterday, a favorable wind profile is in place with mostly southwesterly flow expected through the afternoon, with potential turning towards westerly late in the day. 11 a.m. surface pressure gradients were weakly favorable with 2.4 mb Newport-Salem and 0.7 mb Salem-Redford. Gradient stacking against easterly transport could be an issue later this afternoon as the Cascades are heating up faster than the valley. The gradient pattern will be monitored closely. If stacking does not occur we should get some favorable open burning conditions within the next few hours. TODAY'S FORECAST: Mostly cloudy this afternoon. A few light showers are possible on the western side of the valley through the day. Salem's high temperature today will be in the low 80s. Relative humidity: Drops to near 40% by 4 p.m. Surface winds: Light and variable, becoming SW 5-10 mph this afternoon. Transport winds: SW 10 mph this afternoon. Mixing height: Rising to 3500 feet late this afternoon. Salem's sunset tonight: 8:18 p.m. (Salem Airport data for Wednesday, Aug. 14th: High 87?F; Rainfall .00") (Maximum Ventilation Index expected today: 35) EXTENDED DISCUSSION: The upper trough will remain off the coast and elongate on Friday. Southwesterly transport wind directions are forecast to continue for the afternoon under mostly cloudy skies, with a chance of showers late. Potential burning conditions exist for the afternoon and we will closely monitor guidance this afternoon and tomorrow morning. More of an onshore pattern is forecast for Saturday as surface temperatures continue near to just below the seasonal average. Morning low clouds are a possibility. No major changes are forecast for Sunday and low clouds are again possible early in the 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 (ft) times the transport wind speed (mph) 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. Doug Wesley ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Fri Aug 16 08:43:50 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 16 Aug 2013 08:43:50 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast_doug.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT FRI AUG 16, 2013 BURN ADVISORY: Recommended burn times for agricultural burning are 2:00 p.m. to 6:30 p.m. Prep burning is not allowed. WEATHER DISCUSSION: Cloudy skies and very humid conditions continue to dominate over the Silverton Hills and Willamette Valley this morning, ahead of the stationary upper trough off the Oregon coast. A band of light rain currently extends from Corvallis northeastward up into the Hood River/The Dalles region east of Portland. Showers appear to be affecting some of higher portions of the Silverton Hills area at this time, and areas that are receiving significant rain are not likely to dry sufficiently this afternoon for any burning operations. A few hundredths of an inch of precipitation was reported this morning at Jordan, Stayton, Lebanon and Russellville. Any other rural precipitation reports would be appreciated here. Surface heating will again be limited today, due primarily to the cloud cover. The 3000+ feet level likely will not be reached until mid-afternoon. Like yesterday, a favorable wind profile is in place with mostly southwesterly transport flow through the afternoon, potentially directed more toward westerly late in the day. Currently surface pressure gradients are weak with 2.0 mb Newport-Salem and -0.6 mb Salem-Redmond. Gradient stacking against easterly transport could again be an issue later this afternoon as areas east of the Cascades are heating up faster than the local valley/hills. The gradient pattern will be monitored closely. High surface humidities are in place and this could pose another problem again today. The readings appear to be likely to stay well above 50% at least through mid-afternoon, as we won't have a drying mechanism until at least tomorrow afternoon. TODAY'S FORECAST: Mostly cloudy today. A few light showers are possible through the day, with a better chance of measurable rain over the hills. Salem's high temperature today will be around 80. Relative humidity: Drops to near 55% by 4 p.m. Surface winds: Light and variable, becoming W 5-10 mph this afternoon. Transport winds: SW 10 mph this afternoon. Mixing height: Rising to 3000-3500 feet late this afternoon. Salem's sunset tonight: 8:16 p.m. (Salem Airport data for Thursday, Aug. 15th: High 80?F; Rainfall T) (Maximum Ventilation Index expected today: 25) EXTENDED DISCUSSION: The upper trough to the west will weaken and elongate this weekend, and generally westerly upper flow will be in place by Sunday with a drying trend setting in at low levels. Significant cloud cover over the hills is not expected Saturday or Sunday afternoons, although some onshore flow is expected both evenings. Broad upper ridging will likely set in early next week with mostly dry and warm conditions at low levels. Northerly low-level flow appears likely to take over with potentially a westerly component late in the days on Monday/Tuesday. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer (ft) times the transport wind speed (mph) 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. Doug Wesley ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Fri Aug 16 11:46:02 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 16 Aug 2013 11:46:02 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_doug.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT FRI AUG 16, 2013 BURN ADVISORY: Recommended burn times for agricultural burning are 2:00 p.m. to 6:30 p.m. Prep burning is not allowed. WEATHER DISCUSSION: Mostly cloudy skies and very humid conditions continue to dominate over the Silverton Hills and Willamette Valley today, ahead of the stationary upper trough off the Oregon coast. Light showers have mostly moved off to the north and east late this morning. Surface heating will again be limited today, due primarily to the cloud cover. The 3000+ feet mixing level likely will be reached by 1-2 pm. Like yesterday, a favorable wind profile is in place with mostly southwesterly transport flow through the afternoon, likely shifting to westerly late in the day. Surface winds, now weak, will also be westerly later today. Currently surface pressure gradients are weakly positive with 2.7 mb Newport-Salem and 0.5 mb Salem-Redmond. Gradient stacking and potential down-mixing could again be an issue later as the latter gradient continues to increase this afternoon (areas east of the Cascades are heating up faster than the local valley/hills). The gradient pattern will continue to be monitored closely. High surface humidities are persistent and this is another limiting factor again today. The readings appear to be likely to stay well above 50% at least through mid-afternoon, as we won't have a significant drying mechanism until at least tomorrow afternoon. TODAY'S FORECAST: Mostly cloudy today. A few light showers are possible through the afternoon, but no significant rain expected. Salem's high temperature today will be around 80. Relative humidity: Drops to near 55% by 4 p.m. Surface winds: Light and variable, becoming W 5-10 mph this afternoon. Transport winds: SW to W 10 mph this afternoon. Mixing height: Rising to 3000-3500 feet later this afternoon. Salem's sunset tonight: 8:16 p.m. (Salem Airport data for Thursday, Aug. 15th: High 80?F; Rainfall T) (Maximum Ventilation Index expected today: 30) EXTENDED DISCUSSION: The upper trough to the west will weaken and elongate this weekend, and generally westerly upper flow will be in place by Sunday with a drying trend at low levels. Significant cloud cover over the hills is doubtful for late Saturday, and not expected Sunday afternoon, although some onshore flow is expected both evenings. Morning cloud cover is also expected both days. Broad upper ridging will likely set in early next week with mostly dry and warm conditions at low levels. Northerly low-level flow appears likely to take over with potentially a westerly transport component late in the days on Monday/Tuesday. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer (ft) times the transport wind speed (mph) 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. Doug Wesley ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: Silverton Hills Midday Forecast_doug.doc Type: application/msword Size: 32768 bytes Desc: Silverton Hills Midday Forecast_doug.doc URL: From willamette-fcst at listsmart.osl.state.or.us Fri Aug 16 11:48:41 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 16 Aug 2013 11:48:41 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_doug.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT FRI AUG 16, 2013 BURN ADVISORY: Recommended burn times for agricultural burning are 2:00 p.m. to 6:30 p.m. Prep burning is not allowed. WEATHER DISCUSSION: Mostly cloudy skies and very humid conditions continue to dominate over the Silverton Hills and Willamette Valley today, ahead of the stationary upper trough off the Oregon coast. Light showers have mostly moved off to the north and east late this morning. Surface heating will again be limited today, due primarily to the cloud cover. The 3000+ feet mixing level likely will be reached by 1-2 pm. Like yesterday, a favorable wind profile is in place with mostly southwesterly transport flow through the afternoon, likely shifting to westerly late in the day. Surface winds, now weak, will also be westerly later today. Currently surface pressure gradients are weakly positive with 2.7 mb Newport-Salem and 0.5 mb Salem-Redmond. Gradient stacking and downward-mixing could again be an issue later as the latter gradient continues to increase this afternoon (areas east of the Cascades are heating up faster than the local valley/hills). The gradient pattern will continue to be monitored closely. High surface humidities are persistent and this is another limiting factor again today. The readings appear to be likely to stay well above 50% at least through mid-afternoon, as we won't have a drying mechanism until at least tomorrow afternoon. TODAY'S FORECAST: Mostly cloudy today. A few light showers are possible through the afternoon, but no significant rain expected. Salem's high temperature today will be around 80. Relative humidity: Drops to near 55% by 4 p.m. Surface winds: Light and variable, becoming W 5-10 mph this afternoon. Transport winds: SW to W 10 mph this afternoon. Mixing height: Rising to 3000-3500 feet later this afternoon. Salem's sunset tonight: 8:16 p.m. (Salem Airport data for Thursday, Aug. 15th: High 80?F; Rainfall T) (Maximum Ventilation Index expected today: 30) EXTENDED DISCUSSION: The upper trough to the west will weaken and elongate this weekend, and generally westerly upper flow will be in place by Sunday with a drying trend at low levels. Significant cloud cover over the hills is doubtful for late Saturday, and not expected Sunday afternoon, although some onshore flow is expected both evenings. Morning cloud cover is also expected both days. Broad upper ridging will likely set in early next week with mostly dry and warm conditions at low levels. Northerly low-level flow appears likely to take over with potentially a westerly transport component late in the days on Monday/Tuesday. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer (ft) times the transport wind speed (mph) 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. Doug Wesley ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Mon Aug 19 08:39:49 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 19 Aug 2013 08:39:49 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_Pete.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT MON AUG 19, 2013 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is allowed from 1 p.m. to 3 p.m. with a 50 acre limit. WEATHER DISCUSSION: A flat upper-level ridge of high pressure is producing a dry and stable westerly flow aloft over Oregon. Only patchy marine clouds were able to form in the Willamette Valley this morning, so sunny skies will prevail today. NE transport winds this morning will turn northerly and increase this afternoon. A weak weather system is forecast to cut across southern British Columbia today. Slight upper-level cooling will provide good afternoon mixing, but transport winds will likely remain too northerly to allow for much burning. TODAY'S FORECAST: Sunny and warm. Increasing north winds in the afternoon. Salem's high temperature today will be near 86 degrees (normal is 82). Relative humidity: Drops to 50% by noon and to near 35% by 5 p.m. Surface winds: N 5-10 mph this morning; N 10-15 mph this afternoon; possibly turning NNW late this afternoon. Transport winds: NNE 7-12 mph this morning; N 10-15 mph this afternoon; possibly turning NNW late this afternoon. Mixing height: Rising to 3000 feet by noon and to near 5000 feet by 5 p.m. Salem's sunset tonight: 8:11 p.m. (Salem Airport data for Sunday, Aug. 18th: High 87?F; Rainfall .00") (Maximum Ventilation Index expected today: 75) EXTENDED DISCUSSION: The upper-level ridge is forecast to strengthen over Oregon on Tuesday, with slackening winds aloft. Warmer air aloft will make for lower afternoon mixing heights, even with surface temperatures climbing into the mid to upper 80s. Prevailing northerly transport winds will limit burning opportunities. The flow aloft will turn weakly southwesterly on Wednesday, with an upper-level disturbance, over northern California, likely triggering afternoon thundershowers across southern Oregon. Sunny skies and northerly transport winds should continue to prevail over NW Oregon with temperatures warming into the low 90s. The upper-level disturbance over northern California is forecast to lift northeastward, into SE Oregon, by Thursday afternoon, which will trigger thunderstorms across much of southern and eastern Oregon. Dry conditions will continue across NW Oregon, but increasing westerly flow aloft will initiate a cooling trend. Transport winds may turn enough onshore to provide a burning opportunity. Increasing southwesterly flow aloft is forecast to drive a weak weather system onshore Friday afternoon, which also may 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 (ft) times the transport wind speed (mph) 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_Pete.doc Type: application/msword Size: 31744 bytes Desc: Silverton Hills Midday Forecast_Pete.doc URL: From willamette-fcst at listsmart.osl.state.or.us Mon Aug 19 11:50:33 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 19 Aug 2013 11:50:33 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_Pete.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT MON AUG 19, 2013 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is allowed from 1 p.m. to 3 p.m. with a 50 acre limit. WEATHER DISCUSSION: A flat upper-level ridge of high pressure is producing a dry and stable westerly flow aloft over Oregon. Expect sunshine and increasing north winds this afternoon. A weak weather system, cutting across southern British Columbia, will slightly cool the air aloft; making for good afternoon mixing. Onshore pressure gradients are already favorable to suppress down-mixing of smoke, so the limiting factors for burning today will be transport wind direct and low-level wind speeds. Surface wind speeds will likely exceed 10 mph later this afternoon and may become strong enough to inhibit vertical plume development. Northerly transport winds are forecast to possibly turn northwesterly this afternoon, which would be more favorable for burning. PIBALS are scheduled to begin at 1 p.m. to monitor both low-level wind speeds and transport wind direction. TODAY'S FORECAST: Sunny and warm. Increasing north winds; possibly turning northwesterly. Salem's high temperature today will be near 86 degrees (normal is 82). Relative humidity: Drops to near 35% by 5 p.m. Surface winds: N 10-15 mph this afternoon; possibly veering to NW. Transport winds: N 10-15 mph this afternoon; possibly veering to NW. Mixing height: Rising to near 5000 feet by 5 p.m. Salem's sunset tonight: 8:11 p.m. (Salem Airport data for Sunday, Aug. 18th: High 87?F; Rainfall .00") (Maximum Ventilation Index expected today: 75) EXTENDED DISCUSSION: The upper-level ridge is forecast to strengthen over Oregon on Tuesday, with slackening winds aloft. Warmer air aloft will make for lower afternoon mixing heights, even with surface temperatures climbing into the mid to upper 80s. Northerly transport winds will limit burning opportunities. The flow aloft will turn weakly southwesterly on Wednesday, with an upper-level disturbance, over northern California, likely triggering afternoon thundershowers across southern Oregon. Sunny skies and northerly transport winds should continue to prevail over NW Oregon with temperatures warming into the low 90s. A significant burning opportunity is not likely. The upper-level disturbance over northern California is forecast to lift northeastward, into SE Oregon, by Thursday afternoon, which will trigger thunderstorms across much of southern and eastern Oregon. Dry conditions will continue across NW Oregon, but increasing westerly flow aloft will initiate a cooling trend. Transport winds may turn enough onshore to provide a burning opportunity. Increasing southwesterly flow aloft is forecast for Friday. Dry conditions should continue, with an approaching weak weather system possibly generating enough onshore flow to create another 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 (ft) times the transport wind speed (mph) divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Tue Aug 20 08:50:58 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 20 Aug 2013 08:50:58 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_Pete.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT TUE AUG 20, 2013 BURN ADVISORY: Agricultural Burning: North of Salem: Recommended agricultural burn times are noon to 6 p.m. >From Salem south: Agricultural burning is not recommended. Prep burning is not allowed. WEATHER DISCUSSION: The weak weather system that pushed across southern British Columbia yesterday has moved well east of the region, which is allowing the upper-level ridge to rebuild over Oregon today. Patchy low clouds in the Willamette Valley this morning should quickly give way to sunshine, with temperatures warming into the mid to upper 80s this afternoon. At the surface, a thermal trough is building northward along the southern Oregon Coast. Onshore pressure gradients have relaxed across NW Oregon and are turning northerly. The Salem sounding this morning showed brisk NE winds from just above the surface through 3000 feet. Transport winds should remain mostly northeasterly today, which is not favorable for burning. Warming aloft will also slightly suppress mixing heights. TODAY'S FORECAST: Areas of morning low clouds; sunny, warm, and breezy this afternoon. Salem's high temperature today will be near 87 degrees (normal is 82). Relative humidity: Drops to 50% by noon and to near 30% by 5 p.m. Surface winds: NNE 5-10 mph this morning; NNE 10-15 mph this afternoon. Transport winds: NE 10-15 mph this morning; NE 15-20 mph this afternoon. Mixing height: Rising to 3000 feet at noon and to near 4500 feet by 5 p.m. Salem's sunset tonight: 8:09 p.m. (Salem Airport data for Monday, Aug. 19th: High 87?F; Rainfall .00") (Maximum Ventilation Index expected today: 90) EXTENDED DISCUSSION: The flow aloft will turn weakly southwesterly on Wednesday, with continued warming aloft over Oregon. An upper-level disturbance, over northern California, will trigger afternoon thundershowers across much of southern Oregon, but skies should remain sunny over NW Oregon. Transport winds are forecast to remain generally northeasterly. An upper-level disturbance is forecast to lift out of northern California, on Thursday, into south-central Oregon. That will likely trigger widespread thundershower activity from the Cascades eastward. Skies should remain mostly sunny across NW Oregon, but increasing onshore flow will initiate a cooling trend and may create an afternoon burning opportunity. Increasing southwesterly flow aloft will bring dry but cooler conditions on Friday. An approaching weak weather system may increase the onshore gradients enough to allow for some afternoon 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 (ft) times the transport wind speed (mph) divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Tue Aug 20 11:36:46 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 20 Aug 2013 11:36:46 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_Pete.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT TUE AUG 20, 2013 BURN ADVISORY: Agricultural Burning: North of Salem: Recommended agricultural burn times are noon to 6 p.m. >From Salem south: Agricultural burning is not recommended. Prep burning is not allowed. WEATHER DISCUSSION: An upper-level ridge of high pressure is strengthening over Oregon today. At the surface, a thermal trough is building northward along the southern Oregon Coast. Although pressure gradients are still weakly onshore, from Newport to Redmond, Willamette Valley surface winds have turned north to northeasterly. The Salem sounding this morning showed brisk NE winds from just above the surface through 3000 feet, and ODF SODAR was showing brisk low-level NE winds, in the coast range, late this morning. Brisk transport winds should remain mostly northeasterly today, which is not favorable for burning. Warming aloft will also slightly suppress mixing heights. A 3 p.m. PIBAL is scheduled to confirm the NE transport winds. TODAY'S FORECAST: Sunny, warm, and breezy this afternoon. Salem's high temperature today will be near 87 degrees (normal is 82). Relative humidity: Drops to near 30% by 5 p.m. Surface winds: NNE 10-15 mph this afternoon. Transport winds: NE 15-20 mph this afternoon. Mixing height: Rising to near 4500 feet by 5 p.m. Salem's sunset tonight: 8:09 p.m. (Salem Airport data for Monday, Aug. 19th: High 87?F; Rainfall .00") (Maximum Ventilation Index expected today: 90) EXTENDED DISCUSSION: The flow aloft will turn weakly southwesterly on Wednesday, with continued warming aloft over Oregon. An upper-level disturbance, over northern California, will trigger afternoon thundershowers across much of southern Oregon, but skies should remain sunny over NW Oregon. Transport winds are forecast to remain generally north to northeasterly; shearing to south-southwesterly at the mixing height. Winds aloft are forecast to turn more southerly on Thursday...sending the upper-level disturbance into south-central Oregon. That will likely trigger widespread thundershower activity...mainly from the Cascades eastward. It is possible that thundershowers could make it over the Willamette Valley. That will need to be closely watched. At least some increase in cloud-cover is likely. If thundershowers remain well east of the region, increasing low-level NW winds will initiate a cooling trend and may create an afternoon burning opportunity. Southwesterly flow aloft will bring dry but cooler conditions on Friday. An approaching weak weather system is forecast to turn winds southwesterly, Friday afternoon, which may combine with cooling aloft to create very favorable burning conditions. 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 (ft) times the transport wind speed (mph) divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Wed Aug 21 08:49:44 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 21 Aug 2013 08:49:44 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast_doug.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT WED AUG 21, 2013 BURN ADVISORY: Agricultural Burning: North of Salem: Recommended agricultural burn times are 11 a.m. to 6 p.m. >From Salem south: Agricultural burning is not recommended. Prep burning is not allowed. WEATHER DISCUSSION: Weak upper ridging is in place today over western OR, ahead of a small closed low off the central CA coast. At the surface, a thermal trough has developed over southwestern Oregon. Surface winds currently mostly weak from the northeast. Middle and upper cloudiness is extensive over portions of the southern half of the state this morning. The Salem sounding this morning continued to show brisk NNE winds from just above the surface through 4000 feet, and ODF SODAR measurements are similar for the coast range. Brisk transport winds should remain mostly north to northeasterly today, which is not favorable for burning. Significant warming aloft has occurred overnight, and this will lead to even warmer surface temperatures this afternoon while mixing heights should be similar to those observed yesterday. TODAY'S FORECAST: Becoming partly cloudy, warm, and breezy this afternoon. Hazy conditions will persist. Salem's high temperature today will be near 90 degrees (average is 82). Relative humidity: Drops to near 25% by 5 p.m. Surface winds: N 10-15 mph this afternoon. Transport winds: NNE 15-20 mph this afternoon. Mixing height: Rising to near 3500 feet by 5 p.m. Salem's sunset tonight: 8:09 p.m. (Salem Airport data for Tuesday, Aug. 20th: High 86?F; Rainfall .00") (Maximum Ventilation Index expected today: 50) EXTENDED DISCUSSION: The upper level low pressure system is forecast to slowly approach OR from the south on Thursday, with increasing clouds and much weaker transport winds possibly turning to the south. Cooler surface temperatures are expected. Showers/thunderstorms will likely be confined to east of the region late in the day, including the eastern portions of the Cascade Range. Wetting rains are not expected over the Silverton Hills. A more favorable onshore pattern with cooler conditions and southwesterly flow aloft is expected for Friday. Cloud cover may be a limiting factor as extensive morning cloudiness is expected and how fast that dissipates later will be key to getting mixing heights to a significant level. We will monitor new model guidance for Friday's forecast. 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 (ft) times the transport wind speed (mph) 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. Doug Wesley ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Wed Aug 21 11:45:51 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 21 Aug 2013 11:45:51 -0700 Subject: [willamette-fcst] Silverton Hills PM Forecast_doug.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT WED AUG 21, 2013 BURN ADVISORY: Agricultural Burning: North of Salem: Recommended agricultural burn times are 11 a.m. to 6 p.m. >From Salem south: Agricultural burning is not recommended. Prep burning is not allowed. WEATHER DISCUSSION: Weak upper ridging is in place today over western OR, ahead of a small closed low off the central CA coast. At the surface, a thermal trough has developed over southwestern Oregon extending northward into the Willamette Valley. Surface winds currently mostly weak from the north-northeast 5-10 mph. Middle and upper cloudiness is scattered through most of the state currently. The Salem outlook for the remainder of the day shows NNE winds from just above the surface through 3000-3500 feet. Transport winds should remain mostly north to northeasterly today, which is not favorable for burning, and will increase a bit late today. Very warm surface temperatures will continue this afternoon and mixing heights should be similar to those observed yesterday. TODAY'S FORECAST: Partly cloudy and very warm this afternoon. Hazy conditions will persist. Salem's high temperature today will be near 90 degrees (average is 82). Relative humidity: Drops to near 25% by 5 p.m. Surface winds: N 5-15 mph this afternoon. Transport winds: NNE 10-20 mph this afternoon. Mixing height: Rising to near 3500 feet by 5 p.m. Salem's sunset tonight: 8:08 p.m. (Salem Airport data for Tuesday, Aug. 20th: High 86?F; Rainfall .00") (Maximum Ventilation Index expected today: 50) EXTENDED DISCUSSION: The upper level low pressure system is forecast to slowly approach OR from the south on Thursday, with increasing clouds and much weaker transport winds possibly turning to the south/southwest. Cooler surface temperatures are expected. Showers/thunderstorms will mostly be confined to east of the region late in the day, including the eastern portions of the Cascade Range, but some late shower activity is possible over Cascade foothills on the western side. A more favorable onshore pattern with cooler conditions and southwesterly to westerly flow aloft is expected for Friday. Cloud cover may be a limiting factor as extensive morning cloudiness is possible. How fast that dissipates later will be key to getting mixing heights to a significant level. 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 (ft) times the transport wind speed (mph) 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. Doug Wesley ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Thu Aug 22 08:45:41 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 22 Aug 2013 08:45:41 -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 THU AUG 22, 2013 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. WEATHER DISCUSSION: Upper level ridge is over the region to the north and east with an upper low to the south along the northern California coast. This low is rotating clouds, showers and thundershowers up from the south. A few lightning strikes have shown up to our south in Linn and Lane County. The surface thermal trough is in the Willamette Valley this morning with an onshore pressure gradient of 3.5 mb from Newport to Salem but an offshore pressure gradient of -2.0 mb from Salem to Redmond. The morning sounding shows very stable conditions with very light NW to NE winds. The upper low will continue to move up from the south today bringing the chance of showers or thundershowers over the region but mainly over the Cascades. Clouds will be variable throughout the day. The pressure gradient will slowly turn more onshore later this afternoon but mixing will remain quite poor - under 3000 ft. (Salem Airport data for Wednesday, August 21st: High 91?F; Rainfall .00") (Maximum Ventilation Index expected today: 20) TODAY'S FORECAST: Variable clouds with chance of showers or thundershowers. Salem's high temperature today will be near 85. Relative humidity drops to 50% around noon. Minimum RH 35-40%. Surface winds: Light and variable during the morning to early afternoon. SW to W at 3-7 mph during the afternoon. Transport winds: Light and variable during the morning. S to W at 4-8 mph during the afternoon. Maximum mixing height: 2700 ft. Sunset tonight: 8:06 p.m. EXTENDED DISCUSSION: Upper level low kicks out to the northeast overnight and into Friday leaving the region under dry southwest flow aloft with a trough off the coast. Onshore flow will bring marine low clouds into the region overnight tonight and into Thursday morning. Expect some clearing tomorrow afternoon. If there's enough clearing there should be a burn opportunity with mixing heights rising to 4000-5000 ft and wind flow SW'erly. Over the weekend and into early next week the trough off the coast moves in closer and strengthens. Expect a pretty deep marine layer with a chance of drizzle or light showers. Expect cooler conditions with high temperatures potentially staying in the upper 60s. Wind flow will be light during the early morning becoming NW'erly during the late morning and 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. Nick Yonker ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Thu Aug 22 11:48:59 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 22 Aug 2013 11:48:59 -0700 Subject: [willamette-fcst] Silverton Hills Field Burning Forecast - Noon Update Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT THU AUG 22, 2013 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. WEATHER DISCUSSION: An upper low is to the south of the region rotating clouds, showers and thundershowers toward the Willamette Valley. Radar echoes show showers to the NE of Salem in the Cascades and echoes moving north through the Roseburg area. The surface thermal trough is still in the Willamette Valley this morning but moving eastward. Newport to Salem pressure gradient is 3.0 mb with a pressure gradient of -1.2 mb from Salem to Redmond. The upper low will continue to move up from the south today bringing the chance of showers or thundershowers over the region but mainly over the Cascades. Clouds will be variable throughout the day. The pressure gradient will slowly turn more onshore later this afternoon but mixing will remain quite poor - under 3000 ft. (Salem Airport data for Wednesday, August 21st: High 91?F; Rainfall .00") (Maximum Ventilation Index expected today: 20) TODAY'S FORECAST: Variable clouds with chance of showers or thundershowers. Salem's high temperature today will be near 83. Relative humidity drops to 50% around 1 p.m.. Minimum RH near 40%. Surface winds: Light and variable during the morning to early afternoon. SW to W at 3-7 mph during the afternoon. Transport winds: Light and variable during the morning. S to W at 4-8 mph during the afternoon. Maximum mixing height: 2700 ft. Sunset tonight: 8:06 p.m. EXTENDED DISCUSSION: Upper level low kicks out to the northeast overnight and into Friday leaving the region under dry southwest flow aloft with a trough off the coast. Onshore flow will bring marine low clouds into the region overnight tonight and into Friday morning. Expect some clearing tomorrow afternoon. If there's enough clearing there should be a burn opportunity with mixing heights rising to 4000-5000 ft and wind flow SW'erly. Over the weekend and into early next week the trough off the coast moves in closer and strengthens. Expect a pretty deep marine layer with a chance of drizzle or light showers. Expect cooler conditions with high temperatures potentially staying in the upper 60s. Wind flow will be light during the early morning becoming NW'erly during the late morning and 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. Nick Yonker ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Fri Aug 23 08:42:30 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 23 Aug 2013 08:42:30 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast_doug.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT FRI AUG 23, 2013 BURN ADVISORY: Recommended times for agricultural burning are 11:00 a.m. to 6:00 p.m. Prep burning is not allowed. WEATHER DISCUSSION: Our meteorological setup is quite different today. We have mostly cloudy conditions over the Willamette Valley and Silverton Hills this morning, behind the upper wave that moved off to the north last night. Rain late yesterday has left us with wet fields. Low clouds will be dominant through most of the morning as onshore flow is prevailing. Generally southwesterly transport winds will likely prevail through the afternoon, with partly cloudy skies expected by early afternoon and cooler surface conditions. If the low cloud does burn off significantly, mixing heights from mid-afternoon through early evening will be favorable. The pressure gradient pattern will slowly improve this afternoon in this scenario and surface humidities should decrease to below 50% by mid afternoon. Ventilation will be significantly improved compared to yesterday after the low cloud coverage decreases. However conditions will be closely monitored as the low cloud may not burn off sufficiently. (Salem Airport data for Thursday, August 22nd: High 86?F; Rainfall .02") (Maximum Ventilation Index expected today: 30) TODAY'S FORECAST: Cooler today; mostly cloudy this morning becoming partly cloudy this afternoon. Salem's high temperature today will be in the upper 70s. Relative humidity drops to below 50% during the early afternoon. Late afternoon 40-45%. Surface winds: Weak southerly during the morning. SW to W at 5-10 mph by late afternoon. Transport winds: WSW 10 mph by afternoon with some strengthening late this afternoon. Maximum mixing height: 3000-3500 ft. Sunset tonight: 8:04 p.m. EXTENDED DISCUSSION: Cooler than average surface temperatures and onshore conditions will likely prevail through the weekend, with the likelihood of morning low clouds. These low clouds should burn off at least partially by early afternoon over the area on both days, yielding to partly cloudy afternoons but with scattered showers developing late over the Cascades and coastal ranges. However in general widespread afternoon clouds over the Silverton Hills is not expected either Saturday or Sunday. This onshore, cool pattern with periods of sunshine and a westerly component to afternoon transport winds looks to persist into early next week with potential favorable burning conditions. 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. Doug Wesley ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Fri Aug 23 11:45:01 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 23 Aug 2013 11:45:01 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_doug.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT FRI AUG 23, 2013 BURN ADVISORY: Recommended time for agricultural burning is from now to 6:00 p.m. Prep burning is not allowed. WEATHER DISCUSSION: Mostly cloudy conditions continue late this morning over the Willamette Valley and Silverton Hills, with initiation of cloud dissipation confined to the higher Cascades. Wet fields continue and drying will be dependent on the cloud evolution. Low clouds will be dominant through at least early afternoon and possibly later. Due to the lack of solar heating today, the gradient pattern in place is not favorable and mixing heights are currently rather low. We may be partly cloudy at best late this afternoon. Generally southwesterly transport winds will likely prevail through the afternoon, with some clearing expected by mid afternoon and cool surface conditions. If the low cloud does burn off significantly, mixing heights from mid-afternoon through early evening will be somewhat favorable. The pressure gradient pattern will slowly improve this afternoon in this scenario and surface humidities should decrease to below 50% by mid afternoon if we get some clearing. However conditions will need to be closely monitored as the low cloud is not burning off yet and if this continues conditions for burning will not occur. (Salem Airport data for Thursday, August 22nd: High 86?F; Rainfall .02") (Maximum Ventilation Index expected today: 30) TODAY'S FORECAST: Mostly cloudy early this afternoon, becoming partly cloudy late afternoon. Salem's high temperature today will be in the mid 70s. Relative humidity drops to below 55% during the early afternoon. Late afternoon 45-50%. Surface winds: Weak southerly, becoming SW-W 5-10 mph by late afternoon. Transport winds: WSW 10 mph with some strengthening late this afternoon. Maximum mixing height: 2500-3000 ft. Sunset tonight: 8:04 p.m. EXTENDED DISCUSSION: Cooler than average surface temperatures and onshore conditions will likely prevail through the weekend, with the likelihood of morning low clouds. Once again, for Saturday these low clouds may not burn off completely; the highest chance of burning off would be the higher hills. At this point, widespread cloudy conditions are doubtful for early afternoon, but a complicating factor is that cloudiness and showers will increase in those areas late in the day also as the heating increases. For Sunday, low clouds are also likely in the morning, and latest model guidance suggests an increased coverage of late-day showers and thunderstorms. This onshore, cool pattern with periods of clouds and a westerly component in the transport winds looks to persist into early next week. On Monday and Tuesday, potential favorable burning conditions will likely exist if clearing and surface warming occurs during the early afternoon hours. At this point it appears that the better chance of this occurring is on Tuesday. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer times the transport wind speed divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Doug Wesley ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Mon Aug 26 08:49:01 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 26 Aug 2013 08:49:01 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_Pete.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT MON AUG 26, 2013 BURN ADVISORY: Agricultural Burning is not recommended. Prep burning is not allowed. WEATHER DISCUSSION: A moist south-southwesterly flow aloft directed a weather system across Oregon Sunday afternoon and evening. The bulk of the shower and thundershower activity was focused across a path from SW Oregon, along the Cascades, and over central Oregon. However, some showers did make their way into the Willamette Valley, where rainfall totals were mostly around one-tenth of an inch. An autumn-like upper-level trough remains anchored in the eastern Gulf of Alaska this morning, with brisk southwesterly flow aloft over Oregon. However, the region is between weather systems today, and some breaks in the clouds are already appearing across much of western Oregon. The combination of slight warming aloft and some sun-breaks today will help afternoon temperatures climb back into the upper 70s. In addition, south to SW winds should also aid in the drying of damp fields. Brisk southwesterly transport winds and high afternoon mixing heights should be favorable for burning this afternoon, if fields can dry out enough. Fluffing may be necessary. Another weather disturbance will likely spread rain back onto the north coast by late this afternoon. It may bring some light rain to the northern Willamette Valley this evening and tonight, as it stalls over NW Oregon. TODAY'S FORECAST: Mostly cloudy but warmer. Chance of light rain late by evening. Salem's high temperature today will be near 77 degrees (normal is 81). Relative humidity: Drops to 60% by noon and to near 45% by 5 p.m. Surface winds: S 5-10 mph this morning; SSW 10-15 mph this afternoon. Transport winds: SWW 10-15 mph this morning; SW 15-20 mph this afternoon. Mixing height: Rising to 3000 feet by noon and to near 6000 feet by 5 p.m. Salem's sunset tonight: 7:59 p.m. (Salem Airport data for Sunday, Aug. 25th: High 71?F; Rainfall .07") (Maximum Ventilation Index expected today: 120) EXTENDED DISCUSSION: The flow aloft will turn more southerly by Tuesday, with a decaying frontal system keeping skies mostly cloudy over NW Oregon. Southwesterly transport winds will likely remain favorable for burning, but continued warming aloft will begin to suppress mixing. Dampness of fields may also limit burning. A mostly dry day is forecast for Wednesday, ahead of another weather system slated to come onshore Thursday afternoon. Some burning opportunities are possible each day, but that will depend of dampness of fields and the timing of incoming weather systems. 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 (ft) times the transport wind speed (mph) divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Mon Aug 26 11:56:54 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Mon, 26 Aug 2013 11:56:54 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_Pete.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT MON AUG 26, 2013 BURN ADVISORY: Agricultural Burning is not recommended. Prep burning is not allowed. WEATHER DISCUSSION: An autumn-like upper-level trough remains anchored in the eastern Gulf of Alaska, with brisk southwesterly flow aloft over Oregon. The region is between weather systems, at midday. Mostly sunny skies and increasing south winds are aiding in the drying of damp fields across the Willamette Valley. However, some fields may need to be fluffed to be dry enough for burning. The combination of slight warming aloft and sunshine will help temperatures recover into the upper 70s this afternoon. However, the air aloft will remain cool enough for mixing heights to exceed 5000 feet this afternoon. Brisk southwesterly transport winds should be favorable for burning but may be too strong to allow for good vertical smoke plume development. PIBALS will begin at noon to monitor transport wind directions and speeds. A slow-moving weather disturbance, currently just off the Oregon coast, will likely spread rain onto the north coast later this afternoon. Some light rain may progress into the northern Willamette Valley tonight, as the weather system weakens and stalls over NW Oregon. TODAY'S FORECAST: Mostly sunny and breezy through early this afternoon. Increasing clouds later this afternoon with a chance of light rain tonight. Salem's high temperature today will be near 77 degrees (normal is 81). Relative humidity: Drops below 50% by 1 p.m. and to near 40% by 5 p.m. Surface winds: S 10-15; veering to SSW 10-15 mph this afternoon. Transport winds: SSW 15-20 mph; veering to SW 15-20 mph this afternoon. Mixing height: Rising to 5000 feet by 2 p.m. and to near 6000 feet by 5 p.m. Salem's sunset tonight: 7:59 p.m. (Salem Airport data for Sunday, Aug. 25th: High 71?F; Rainfall .07") (Maximum Ventilation Index expected today: 120) EXTENDED DISCUSSION: The flow aloft will turn more southerly by Tuesday, with a decaying frontal system keeping skies mostly cloudy over NW Oregon. Southwesterly transport winds will likely remain favorable for burning, but continued warming aloft will begin to suppress mixing. Dampness of fields may also limit burning. A mostly dry day is forecast for Wednesday, ahead of another weather system slated to come onshore Thursday afternoon. Some burning opportunities are possible each day, but that will depend of dampness of fields and the timing of incoming weather systems. 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 (ft) times the transport wind speed (mph) divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Tue Aug 27 08:58:20 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 27 Aug 2013 08:58:20 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast_Pete.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT TUE AUG 27, 2013 BURN ADVISORY: Agricultural Burning is not recommended. Prep burning is not allowed. WEATHER DISCUSSION: A decaying frontal system stalled near the northern Oregon coast last night; dumping about one-quarter of an inch of rain across the extreme northern Willamette Valley. However, rain totals tapered off rapidly to the south, with only a few hundredths of an inch falling in the Silverton Hills. An autumn-like upper-level trough remains anchored in the eastern Gulf of Alaska this morning, with southwesterly flow aloft holding the surface front in place near the northern Oregon coast. With little movement of the frontal zone expected today, skies should remain partly sunny across the northern Willamette Valley today. That should allow for continued drying of fields. Winds were too strong for burning on Monday. Weaker wind speeds are expected today. Wind directions near the mixing height are forecast to stay mainly southerly, but low-level winds are forecast to veer from southeasterly this morning to more westerly by late this afternoon. The air aloft is still cool enough to support 5000-foot mixing heights. TODAY'S FORECAST: Partly sunny. Not as breezy as it was on Monday. Salem's high temperature today will be near 83 degrees (normal is 81). Relative humidity: Drops to 50% by noon and to near 35% by 5 p.m. Surface winds: SE 4-8 mph this morning; becoming S 5-10 mph early this afternoon and W 5-10 mph late this afternoon. Transport winds: S 10 mph this morning; becoming SW 10-15 mph this afternoon. Mixing height: Rising to 3000 feet by 11 a.m. and to 5000 feet by 2 p.m. Salem's sunset tonight: 7:57 p.m. (Salem Airport data for Monday, Aug. 26th: High 82?F; Rainfall .03") (Maximum Ventilation Index expected today: 75) EXTENDED DISCUSSION: Little change in the weather pattern is expected on Wednesday, with a stationary frontal zone remaining near the northern Oregon coast. Skies should be partly sunny again in the Silverton Hills with very similar winds and mixing heights compared to today. A cold front will push onshore Thursday and should be strong enough to bring rain into the Willamette Valley. Things dry out again on Friday, with continued southwesterly flow aloft. 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 (ft) times the transport wind speed (mph) divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Tue Aug 27 11:55:21 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Tue, 27 Aug 2013 11:55:21 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_Pete.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT TUE AUG 27, 2013 BURN ADVISORY: Agricultural Burning is not recommended. Prep burning is not allowed. WEATHER DISCUSSION: An autumn-like upper-level trough remains anchored in the eastern Gulf of Alaska, with south-southwesterly flow aloft holding a surface front in place near the northern Oregon coast. Satellite imagery shows mostly cloudy skies stretching from western Washington across the NW corner of Oregon, with mostly sunny skies to the south and east. The Silverton Hills are on the eastern edge of the clouds. With little movement of the frontal zone expected, skies should remain partly sunny this afternoon. At the surface, a weak thermal trough is over the Willamette Valley, with light onshore flow from Newport to Salem and light offshore flow from Redmond to Salem. Daytime heating will need to shift the thermal trough into central Oregon, before any burning can occur this afternoon. Wind directions near the mixing height are generally southerly and should shift to south-southwesterly later this afternoon. Low-level winds should also turn southwesterly, as the surface thermal trough shifts east of the region. Those wind-shifts are not likely to occur before 2 p.m., but winds will be monitored, with PIBALS, beginning at noon (to be sure). The air aloft (up through 10,000 feet above the surface) is still cool enough to support 5000-foot mixing heights, once surface temperatures climb into the 80s. TODAY'S FORECAST: Partly sunny. Not as breezy as it was on Monday. Salem's high temperature today will be near 83 degrees (normal is 81). Relative humidity: Drops to near 35% by 5 p.m. Surface winds: Variable 3-6 mph; becoming S 5-10 mph early this afternoon and SW 5-10 mph late this afternoon. Transport winds: S 10 mph; becoming SW 10-15 mph later this afternoon. Mixing height: Rising to 5000 feet by 2 p.m. Salem's sunset tonight: 7:57 p.m. (Salem Airport data for Monday, Aug. 26th: High 82?F; Rainfall .03") (Maximum Ventilation Index expected today: 75) EXTENDED DISCUSSION: Little change in the weather pattern is expected on Wednesday, with a stationary frontal zone remaining near the northern Oregon coast. Skies should be partly sunny again in the Silverton Hills with very similar winds and mixing heights compared to today. Computer models are consistent in showing the offshore upper-level trough moving closer to the coast on Thursday, with a cold front likely spreading wetting rains inland as far as the Willamette Valley. Drier weather is on tap for Friday and Saturday, before a much stronger upper-level trough is forecast to spread rain back across the region Sunday and Monday (Labor 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 (ft) times the transport wind speed (mph) divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Wed Aug 28 08:56:58 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 28 Aug 2013 08:56:58 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast_Pete.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT WED AUG 28, 2013 BURN ADVISORY: Agricultural Burning is not recommended. Prep burning is not allowed. WEATHER DISCUSSION: Little change in the overall weather pattern is expected today, so another significant burning opportunity is likely this afternoon. The most probable timeframe is from 2:00 p.m. until 6:00 p.m. An autumn-like upper-level trough remains anchored in the eastern Gulf of Alaska, with a warm and moist south-southwesterly flow aloft over Oregon. Surges of moisture continue to circulate around the trough, bringing some rain to mainly the coast and the NW corner of the state. A few hundredths of an inch of rain fell in the northern Willamette Valley overnight, including the Silverton Hills. Satellite imagery shows an impressive cloud-shield, associated with a moist frontal system, stretching from just off the southern British Columbia coast southwestward to off the northern California coast. Cloudy skies extend inland across western Washington and much of western Oregon, but the light rain that fell overnight has ended. Skies remain mostly sunny from the Oregon Cascades eastward. The Silverton Hills are on the eastern edge of the clouds. With no significant surge of moisture expected to move onshore today, skies should remain partly sunny. At the surface, a thermal trough extends from central Washington to over the northern Oregon Cascades. Pressure gradients are weakly onshore from Newport to Salem and weakly offshore from Redmond to Salem. Like yesterday, daytime heating should shift the thermal trough into central Oregon this afternoon, which will also turn the flow onshore from Salem to Redmond. Transport wind directions are generally southeasterly this morning but should shift to south-southwesterly this afternoon. Low-level winds should also turn southwesterly, as the surface thermal trough shifts east of the region. Those wind-shifts are likely to occur by 2:00 p.m. The air aloft is still cool enough to support mixing heights above 5000 feet, once surface temperatures climb into the 80s. TODAY'S FORECAST: Partly sunny and warm. Salem's high temperature today will be near 84 degrees (normal is 81). Relative humidity: Drops to 50% by 2 p.m. and to near 40% by 5 p.m. Surface winds: SE 3-7 mph this morning; becoming SW 3-7 mph early this afternoon and W 5-10 mph late this afternoon. Transport winds: SE 5-10 mph this morning; becoming SW 15 mph this afternoon. Mixing height: Rising to 5000 feet by 2 p.m. and to 6000 feet by 5 p.m. Salem's sunset tonight: 7:56 p.m. (Salem Airport data for Tuesday, Aug. 27th: High 85?F; Rainfall Trace) (Maximum Ventilation Index expected today: 90) EXTENDED DISCUSSION: Computer models are consistent in showing the offshore upper-level trough moving closer to the coast on Thursday, with a cold front likely spreading wetting rains inland across the Silverton Hills. The latest guidance suggests about one-tenth of an inch of rain, beginning Thursday morning. Things should dry out Friday, with more sunshine helping temperatures recover back into the 80s Saturday and perhaps Sunday. Another upper-level trough is forecast to spread showers and cooler temperatures back across the region on Monday (Labor 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 (ft) times the transport wind speed (mph) 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_Pete.doc Type: application/msword Size: 33280 bytes Desc: Silverton Hills AM Forecast_Pete.doc URL: From willamette-fcst at listsmart.osl.state.or.us Wed Aug 28 11:56:04 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Wed, 28 Aug 2013 11:56:04 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_Pete.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT WED AUG 28, 2013 BURN ADVISORY: Agricultural Burning is not recommended. Prep burning is not allowed. WEATHER DISCUSSION: The weather pattern today is very similar to what we saw on Tuesday, so another significant burning opportunity is likely this afternoon. The most probable timeframe is from 2:00 p.m. until 6:00 p.m. PIBALS are scheduled to begin at 1:00 p.m. Due to spotty light rain in the northern Willamette Valley overnight, some fields may be damp enough to require fluffing. An autumn-like upper-level trough remains anchored in the eastern Gulf of Alaska, with a warm and moist south-southwesterly flow aloft over Oregon. Surges of moisture continue to circulate around the trough, with the next batch of rain not slated to come onshore until tonight. Midday satellite imagery shows an impressive cloud-shield, associated with a nearly stationary frontal system, stretching from just off the southern British Columbia coast southwestward to off the northern California coast. Cloudy skies extend inland across much of western Oregon, especially from the coast range westward, but no rain is being reported. The Silverton Hills are on the eastern edge of the clouds, with sunshine from the Cascades eastward. At the surface, a thermal trough extends from central Washington to over the northern Oregon Cascades. Pressure gradients are weakly onshore from Newport to Salem and flat from Salem to Redmond. Like yesterday, daytime heating should shift the thermal trough into central Oregon this afternoon, which will increase the onshore gradients; making for favorable burning conditions. Transport wind directions are likely to be southwesterly again this afternoon. Light low-level winds should also turn southwesterly, and eventually westerly; similar to what occurred yesterday. The air aloft is still cool enough to support mixing heights rising above 5000 feet. TODAY'S FORECAST: Partly sunny and warm. Salem's high temperature today will be near 84 degrees (normal is 81). Relative humidity: Drops to 50% by 2 p.m. and to near 40% by 5 p.m. Surface winds: Becoming SW 3-7 mph early this afternoon and W 5-10 mph late this afternoon. Transport winds: Becoming SW 15 mph this afternoon. Mixing height: Rising to near, or above, 5000 feet after 2 p.m. Salem's sunset tonight: 7:56 p.m. (Salem Airport data for Tuesday, Aug. 27th: High 85?F; Rainfall Trace) (Maximum Ventilation Index expected today: 90) EXTENDED DISCUSSION: Computer models are consistent in showing the offshore upper-level trough moving closer to the coast on Thursday, with another surge of moisture likely spreading mostly light rain inland across NW Oregon, beginning Thursday morning. The latest guidance suggests about one-tenth to one-quarter of an inch of rain in the Silverton Hills. Temperatures will drop back into the mid 70s. Things should dry out Friday, with more sunshine helping temperatures recover to near normal. Increasing sunshine will boost temperatures back into the 80s Saturday and Sunday. Another upper-level trough is forecast to spread showers and cooler temperatures back across the region Monday (Labor Day) and/or Tuesday of next week, but this system is showing up as "weaker" with each update of the computer models. 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 (ft) times the transport wind speed (mph) divided by 1000. 4. Surface wind direction is the general expected wind direction. At a specific point surface winds are highly dependent on local terrain conditions. This forecast is provided under an agreement between the Oregon Department of Agriculture and the Oregon Department of Forestry. For information contact ODA at 503-986-4701. Pete Parsons ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Thu Aug 29 08:48:21 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 29 Aug 2013 08:48:21 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast_doug.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT THURS AUG 29, 2013 BURN ADVISORY: Recommended times for agricultural burning are noon to 6 p.m.. Prep burning is not allowed. WEATHER DISCUSSION: The strong upper-level trough is centered just off Oregon's Pacific coastline this morning, and this is creating unsettled, showery conditions over the area and that will persist throughout the day. Rain amounts overnight in the northern Willamette Valley and the Silverton Hills were generally 0.10 to 0.20". Surface pressure gradients are weak at the moment and are not expected to change significantly today. Wind profiles will be generally southwesterly through the day over the area with strong winds above 2000 feet. Surface winds will likely shift to more westerly late in the day. Heating at the surface and mixing heights will be limited compared to yesterday, and even if we partially clear and warm up more than expected, wet fields will likely be a preventative factor for burning. Favorable conditions for burning are not expected overall. Scattered showers will likely continue into the evening; we will closely monitor the situation for updates. TODAY'S FORECAST: Mostly cloudy and cooler with scattered showers through the day and possible thunderstorm activity this afternoon and evening. General rainfall amounts will be light, with local areas of moderate amounts. Salem's high temperature today will be near 76 degrees. Relative humidity: 60-70% by 2 p.m. and to about 55% by 5 p.m.. Surface winds: SE 3-7 mph this morning; becoming SW 5-10 mph early this afternoon and W 5-15 mph late this afternoon. Transport winds: SSW 10-15 this morning becoming SW 20-25 mph this afternoon. Mixing height: Rising to 2500 feet by 2 p.m. and to 3000-3500 feet by 5 p.m.. Salem's sunset tonight: 7:54 p.m. (Salem Airport data for Wed., Aug. 28th: High 82?F and 0.04" rainfall) (Maximum Ventilation Index expected today: 65) EXTENDED DISCUSSION: The trough flattens and warming aloft is in the works for Friday. More sunshine will help temperatures recover to near 80 and southwesterly transport winds continuing. Potential burn conditions in the afternoon are expected. Dry and warm conditions should persist through the weekend. An approaching trough may bring some moisture back into the region early 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 (ft) times the transport wind speed (mph) 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. Doug Wesley ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Thu Aug 29 11:48:46 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Thu, 29 Aug 2013 11:48:46 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_doug.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT THURS AUG 29, 2013 BURN ADVISORY: Recommended times for agricultural burning are now through 6 p.m.. Prep burning is not allowed. WEATHER DISCUSSION: The strong upper-level trough continues to be entrenched just off Oregon's Pacific coastline today, and this is creating unsettled, showery conditions over the area and that will persist throughout the day. Additional wetting rains have covered large portions of the northern Willamette Valley and the Silverton Hills this morning. Surface pressure gradients are weak at the moment and are not expected to get better than a weakly-favorable level today Wind profiles will be generally southwesterly through the day over the area with strong winds above 1000-2000 feet. Surface winds, generally weak SE now, will likely shift to more SW-W as we progress through the afternoon. Heating at the surface and mixing heights is limited compared to yesterday, with some periods of partly cloudy skies possible but continued scattered showers and a possible thunderstorm. Favorable conditions for burning are not expected today. TODAY'S FORECAST: Mostly cloudy and cooler with scattered showers through the day and possible thunderstorm activity this afternoon and evening. General rainfall amounts will be light, with local areas of moderate amounts. Salem's high temperature today will be near 75 degrees. Relative humidity: 60-70% by 2 p.m. and about 55% by 5 p.m.. Surface winds: Becoming SW 5-10 mph early this afternoon and W 5-15 mph late this afternoon. Transport winds: Becoming SW 20-25 mph this afternoon. Mixing height: Rising to 3000-3500 feet by 5 p.m.. Salem's sunset tonight: 7:54 p.m. (Salem Airport data for Wed., Aug. 28th: High 82?F and 0.04" rainfall) (Maximum Ventilation Index expected today: 65) EXTENDED DISCUSSION: The trough flattens and a quieter pattern is in the works for Friday along with drier low-level conditions. More sunshine will help temperatures recover to near 80 late in the day with winds aloft weakening and partly cloudy skies. Potential burn conditions in the afternoon are expected, if fields can dry sufficiently during the late morning and early afternoon. Dry and warm conditions should persist through the weekend. An approaching trough may bring some moisture back into the region by late Monday or Tuesday. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer (ft) times the transport wind speed (mph) 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. Doug Wesley ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Fri Aug 30 08:43:18 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 30 Aug 2013 08:43:18 -0700 Subject: [willamette-fcst] Silverton Hills AM Forecast_doug.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 9:00 AM PDT FRI AUG 30, 2013 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. WEATHER DISCUSSION: Upper-level ridging will begin to take over today, as yesterday's disturbance has moved off to the northeast. This scenario will stabilize the atmosphere today with warmer temperatures at all levels and drier conditions taking over. Some rain showers occurred overnight in portions of the Silverton Hills and that factor along with rains from the last 2 days has generally left us with wet fields. This scenario will improve as the afternoon wears on. The stabilization and upper ridging means that local wind patterns will begin to dominate later today over the area, and winds will be much weaker than yesterday. Northerly surface and transport winds are expected this afternoon, and gradients generally favorable. Winds should switch to northwesterly late in the day and conditions will be monitored closely. If this occurs early enough and sufficient drying at the surface occurs, burning conditions would be in place. TODAY'S FORECAST: Clearing this morning with mostly sunny skies through the bulk of the day and warmer. Salem's high temperature today will be near 82 degrees. Relative humidity: 50-55% by 2 p.m. and 40-45% by 5 p.m.. Surface winds: Near calm this morning, becoming N 5-10 mph by afternoon and NW 5-10 late afternoon. Transport winds: N 5-10 mph by afternoon and NNW 10 mph this afternoon. Mixing height: Rising to 3500-4000 feet by 5 p.m.. Salem's sunset tonight: 7:52 p.m. (Salem Airport data for Thurs., Aug. 29th: High 80?F and 0.17" rainfall) (Maximum Ventilation Index expected today: 35-40) EXTENDED DISCUSSION: After some morning cloudiness Saturday, mostly sunny skies are expected for the region through Sunday as upper ridging continues to strengthen. Surface maximum temperatures are expected to be above average both days. Early next week clouds and moisture will increase as a new trough approaches from the west. Cooler conditions with a chance of showers are expected on Tuesday. At this point, a general rain event is not expected. 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 (ft) times the transport wind speed (mph) 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. Doug Wesley ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: From willamette-fcst at listsmart.osl.state.or.us Fri Aug 30 11:44:59 2013 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Field Burning Forecast) Date: Fri, 30 Aug 2013 11:44:59 -0700 Subject: [willamette-fcst] Silverton Hills Midday Forecast_doug.doc Message-ID: SILVERTON HILLS FIELD BURNING FORECAST OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE 12:00 PM PDT FRI AUG 30, 2013 BURN ADVISORY: Agricultural burning is not recommended. Prep burning is not allowed. WEATHER DISCUSSION: Upper-level ridging is in place today, stabilizing the atmosphere with warmer temperatures at all levels and drier conditions taking over. However, recent rains have left fields too wet for burning and this has continued so far today. As of 11:00 a.m. surface relative humidity measurements are still well above 60% over the Silverton Hills. Gradients are very weak. The stabilization and upper ridging means that local wind patterns are now dominant today over the area. Northerly surface and transport winds are expected this afternoon, with gradients generally weakly favorable. Winds should switch to northwesterly late in the day and conditions will be monitored closely. Surface humidities are expected to decrease significantly by late afternoon. TODAY'S FORECAST: Mostly sunny skies this afternoon. Salem's high temperature today will be near 82 degrees. Relative humidity: 50-55% by 2 p.m. and 40-45% by 5 p.m.. Surface winds: Becoming NE 5-10 mph, then NW 5-10 late afternoon. Transport winds: N 5-10 mph, becoming NNW 10 mph late this afternoon. Mixing height: Rising to 4000-4500 feet by 5 p.m.. Salem's sunset tonight: 7:52 p.m. (Salem Airport data for Thurs., Aug. 29th: High 80?F and 0.17" rainfall) (Maximum Ventilation Index expected today: 45) EXTENDED DISCUSSION: After some morning cloudiness Saturday, mostly sunny skies are expected for the region through Sunday as upper ridging continues to strengthen. Surface maximum temperatures are expected to be above average both days. Early next week clouds and moisture will increase as a new trough approaches from the west. Cooler conditions with a chance of showers are expected on Tuesday, with an onshore wind pattern. At this point, an extensive rain event is not expected on Tuesday. The National Weather Service's digital forecast is available at: http://forecast.weather.gov/MapClick.php?lat=44.90549606158295&lon=-122.8106689453125&site=pqr&unit=0&lg=en&FcstType=text Notes: 1. Mixing height, as used here, is the lowest height at which the potential temperature exceeds the potential temperature at the surface. As a practical matter it is the approximate height to which a smoke plume will rise assuming good ignition, dry fuels, and winds less than about 15mph. 2. Transport winds are a layer average through the mixing height, weighted slightly toward the winds at the top of the layer. 3. Ventilation Index is the height of the mixing layer (ft) times the transport wind speed (mph) 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. Doug Wesley ODF Meteorologist -------------- next part -------------- An HTML attachment was scrubbed... URL: