From willamette-fcst at listsmart.osl.state.or.us Tue Dec 1 09:07:40 2009 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Tue, 01 Dec 2009 11:07:40 -0600 Subject: [willamette-fcst] Forecast - Tuesday, December 1st, 2009 Message-ID: Daily Smoke Management Forecast Oregon Department of Agriculture Smoke Management Program Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts. Issued: Tuesday, December 1st, 2009 at 9:00am. Burn Advisory: Agricultural burning is not recommended. Stack burning is not allowed. Weather Discussion: A very weak cold front dropped southward across Washington Monday, in a dry northwesterly flow aloft. It was falling apart near the Washington/Oregon border this morning. Satellite imagery showed a narrow band of clouds, associated with the cold front, extending across extreme northeastern and north-central Oregon, but neither Doppler radar nor surface reports showed any precipitation. The air aloft is very warm, with the freezing levels over Salem and Medford measured at 9400 and 9600 feet respectively this morning. Strong low-level temperature inversions allowed for the formation of widespread valley fog, on both sides of the Cascades overnight. Surface temperatures dropped into the 20s across most of central and eastern Oregon by early this morning, with some spots, like Lakeview, dipping into the teens. Readings west of the Cascades were mostly in the upper 30s and lower 40s. Visible satellite imagery showed fog covering most valley locations across western Oregon, with mostly clear skies over sections of the coast and higher elevations of the Cascades. The ODA surface analysis showed higher pressure beginning to build over eastern Washington and extreme northeastern Oregon and a thermal trough building northward along the southern Oregon coast. Increasing offshore flow will promote drying of the air mass across western Oregon this afternoon. Fog should clear from areas near the Columbia Gorge by late this morning, with some clearing even making it as far south as the southern Willamette Valley by late this afternoon. A little sunshine will help valley highs climb into the upper 40s in most locations. Surface Winds: NNE 3-10 this morning, NNE 5-15 this afternoon. Transport Winds: NNE 7 this morning, NNE 10 this afternoon. Atmospheric Ventilation Conditions: Maximum mixing height today will be near 1700 feet. Ventilation index 17. High Temperature: Salem\'s high temperature today will be near 48. Humidities: Minimum relative humidity will be near 63%. Sunrise/Sunset: Salem sunset tonight: 4:32pm; sunrise tomorrow: 7:31am. Extended Outlook: The flow aloft is forecast to turn more northerly Wednesday, as the upper-level ridge builds inland over western Canada. Increasing offshore flow, at the surface, will continue to dry out the air mass over western Oregon. Dry easterly winds, from the Columbia Gorge, should keep fog from forming overnight in the extreme northern Willamette Valley, but fog is still likely to form over much of the central and southern valley. Temperatures should drop below freezing across most of the valley Wednesday morning. However, skies should clear across all of the Willamette Valley by Wednesday afternoon, with temperatures recovering into the upper 40s. Not much change is forecast for Thursday, with a frosty morning and dry offshore flow providing plenty of afternoon sunshine. Temperatures will likely cool slightly, as the air mass continues to dry out. The long-range models begin to radically differ beginning Friday, so confidence in the forecast is below average. It would appear likely, however, that colder air will begin moving into the region. The chances for precipitation increase by late Friday, but it could remain dry through the weekend. Tomorrow (02 Dec): Areas of AM Fog South. Becoming Mostly Sunny. 30/48 Thu (03 Dec): Areas of AM Fog...Mainly South. Mostly Sunny. 26/46 Fri (04 Dec): Increasing Clouds. Slight Chance of Rain. 28/45 Sat (05 Dec): Partly Cloudy and Turning Colder. 32/44 Sun (06 Dec): Partly Cloudy and Cold. 26/38 Mon (07 Dec): Mostly Sunny and Cold. 25/33 Tue (08 Dec): Mostly Sunny and Cold. 22/32 ODA Meteorologist weather at oda.state.or.us From willamette-fcst at listsmart.osl.state.or.us Tue Dec 1 12:12:21 2009 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Tue, 01 Dec 2009 14:12:21 -0600 Subject: [willamette-fcst] Forecast - Tuesday, December 1st, 2009 Message-ID: Daily Smoke Management Forecast Oregon Department of Agriculture Smoke Management Program Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts. NOON UPDATE Issued: Tuesday, December 1st, 2009 at 12:00pm. Burn Advisory: Agricultural burning is not recommended. Stack burning is not allowed. Weather Discussion: An upper-level ridge of high pressure, centered just offshore, is producing a dry northwesterly flow aloft over Washington and Oregon. The air aloft is very warm over western Oregon. The freezing levels, over Salem and Medford, were measured at over 9000 feet this morning. Meanwhile, the low-level air mass remains cool and moist enough for widespread fog and low clouds across the valleys of western Oregon. With strong low-level temperature inversions in place, ventilation conditions are poor today across western Oregon. A very weak cold front dropped southward across Washington Monday and brought spotty light rain and snow flurries to sections of north-central and northeastern Oregon this morning. In its wake, cooler and drier air had cleared skies across eastern Washington. Cool and relatively dry air is also beginning to pour into the Columbia Gorge and westward into the extreme northern Willamette Valley. That helped to clear skies in the Portland area this morning. However, fog and low clouds were persisting, at midday, from about Woodburn southward, across the remainder of the Willamette Valley. Skies were mostly sunny along the coast and over the Cascades. The ODA surface analysis showed rising pressures across eastern Washington and north-central Oregon, in response to the cool and dry Canadian air spilling into the region. A weak thermal torugh was also trying to build along the southern Oregon Coast. Increasing offshore flow will promote drying of the air mass across western Oregon today. The low clouds and fog should begin to break up, from north to south, across the Willamette Valley this afternoon. However, some sections of the valley, especially the Eugene area, may stay cloudy all day. Midday temperatures ranged from a cloudy 40 degrees, in the Eugene area, to the upper 40s, with some sunshine, in the northern Willamette Valley and along the coast. Highs this afternoon will likely stay in the low to mid 40s in the south valley but may reach 50 degrees in sunny sections of the north valley and low to mid 50s along the coast. Surface Winds: NNE 5-15 this afternoon. Transport Winds: NNE 10 this afternoon. Atmospheric Ventilation Conditions: Maximum mixing height today will be near 1700 feet. Ventilation index 17. High Temperature: Salem\'s high temperature today will be near 48. Humidities: Minimum relative humidity will be near 63%. Sunrise/Sunset: Salem sunset tonight: 4:32pm; sunrise tomorrow: 7:31am. Extended Outlook: The flow aloft is forecast to turn more northerly Wednesday, as the upper-level ridge builds inland over western Canada. Increasing offshore flow, at the surface, will continue to dry out the air mass over western Oregon. Dry easterly winds, from the Columbia Gorge, should keep fog from forming overnight in the extreme northern Willamette Valley, but fog is still likely to form over much of the central and southern valley. The drier air will allow most valley temperatures to drop below freezing Wednesday morning. However, skies should clear across most, and possibly all, of the Willamette Valley Wednesday afternoon, with temperatures recovering into the mid to upper 40s. The upper-level ridge is forecast to hold over the region Thursday, with a frosty morning and dry offshore flow providing plenty of afternoon sunshine to most of western Oregon. There may still be some persistent areas of fog in the southern valleys. Overnight temperatures will likely cool slightly, as the air mass continues to dry out, but daytime highs should recover close to normal. The upper-level ridge will begin giving way on Friday, with a cool weather system forecast to move from southwestern Canada into Washington and northern Oregon by late in the day. This cold front may be strong enough to bring some light rain and snow to the region, with snow levels dropping to around 1000 feet by Saturday morning. Much colder air is forecast to push southward into Washington and Oregon over the weekend, but it also appears as if the air mass will be drying out at the same time. The cold and dry conditions will likely persist through early next week. Tomorrow (02 Dec): Areas of AM Fog Central and South. Becoming Mostly Sunny. 30/48 Thu (03 Dec): Areas of AM Fog...Mainly South. Mostly Sunny. 26/46 Fri (04 Dec): Increasing Clouds. Slight Chance of Rain late. 28/45 Sat (05 Dec): Chance of Light Rain or Snow Early...Becoming Partly Cloudy. 32/44 Sun (06 Dec): Partly Cloudy and Cold. Slight Chance of Light Snow Early. 26/35 Mon (07 Dec): Sunny and Cold. 22/32 Tue (08 Dec): Sunny and Cold. 20/32 ODA Meteorologist weather at oda.state.or.us From willamette-fcst at listsmart.osl.state.or.us Wed Dec 2 09:08:21 2009 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Wed, 02 Dec 2009 11:08:21 -0600 Subject: [willamette-fcst] Forecast - Wednesday, December 2nd, 2009 Message-ID: Daily Smoke Management Forecast Oregon Department of Agriculture Smoke Management Program Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts. Issued: Wednesday, December 2nd, 2009 at 9:00am. Burn Advisory: Agricultural burning is allowed. Suggested burn times are from 10:00am until 2:30pm. Stack burning is not allowed. Weather Discussion: An upper-level ridge of high pressure, centered just offshore, is producing a dry northerly flow aloft over Washington and Oregon. The air aloft is still very warm over western Oregon. The freezing levels, over Salem and Medford, were measured at 9500 feet and 11,000 feet respectively early this morning. Meanwhile, cool and dry low-level air is filtering southward, across the Willamette Valley. Strong low-level temperature inversions are still in place, but ventilation near the Columbia Gorge has significantly improved due to an increase in easterly winds...gusting to over 30 mph. Northerly winds in the central and southern Willamette Valley are not conducive to good ventilation for stack burning. The cool and dry low-level air helped to keep skies clear of fog in the northern Willamette Valley overnight, but there were still some areas of fog in the south valley this morning. Skies were sunny along the coast and over the Cascades. Temperatures were much cooler this morning, with most of the Willamette Valley dropping to near or below freezing. Mid-morning temperatures ranged from the mid 20s in the south valley to the mid 30s in the north valley. The ODA surface analysis showed pressures rising across eastern Washington and north-central Oregon, in response to the cool and dry Canadian air spilling into the region. A weak thermal torugh was also trying to build along the southern Oregon Coast. The offshore flow will promote further drying of the air mass across western Oregon. Fog should begin to lift, from the southern Willamette Valley this afternoon. Highs this afternoon will likely stay in the 40s in the south valley but may reach the low 50s in parts of the north valley and along the coast. Surface Winds: N 5-15 this morning, NNE 5-15 this afternoon. Transport Winds: N 10 this morning, NNE 10 this afternoon. Atmospheric Ventilation Conditions: Maximum mixing height today will be near 2000 feet. Ventilation index 20. High Temperature: Salem\'s high temperature today will be near 49. Humidities: Minimum relative humidity will be near 40%. Sunrise/Sunset: Salem sunset tonight: 4:32pm; sunrise tomorrow: 7:32am. Extended Outlook: The upper-level ridge is forecast to hold over the region Thursday, with another frosty morning and dry offshore flow providing plenty of afternoon sunshine to most of western Oregon. There may still be a few pockets of fog in the southern Willamette Valley and the southwestern valleys. Overnight temperatures will likely cool slightly, as the air mass continues to dry out, but daytime highs should recover close to normal. A cool weather system is forecast to move from southwestern Canada into Washington and northern Oregon by late Friday. This cold front may be strong enough to bring some light rain and snow to the region, with snow levels dropping to 1000 feet, or lower, by Saturday morning. Much colder air is forecast to push southward into Washington and Oregon over the weekend, but the air mass is forecast to remain mostly dry during the transition into the Arctic air. Quite cold and dry conditions will likely persist through early next week. A westerly flow aloft is forecast to undercut the offshore ridge and begin a warming trend around the middle of next week. That process will need to be closely monitored, for the potential of significant snow and/or ice accumulation, even in the Willamette Valley, as Pacific moisture gets thrown over the existing cold dome of low-level air. Temperatures will likely warm above freezing, in the lowest elevations, by the end of next week, with snow and ice turning to plain old rain in the lowlands. Significant snows may continue in the mountains. Tomorrow (03 Dec): Areas of AM Fog South. Mostly Sunny. NNE Winds. 26/46 Fri (04 Dec): Increasing Clouds. Slight Chance of Light Rain or Flurries Late. 26/45 Sat (05 Dec): Slight Chance of Light Rain or Snow Flurries. 30/44 Sun (06 Dec): Partly Cloudy and Cold. Slight Chance of Light Snow. 26/35 Mon (07 Dec): Sunny and Cold. 22/33 Tue (08 Dec): Sunny and Cold. 20/35 Wed (09 Dec): Good Chance of Snow. Significant Accumulations Possible. 25/33 ODA Meteorologist weather at oda.state.or.us From willamette-fcst at listsmart.osl.state.or.us Wed Dec 2 09:37:55 2009 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Wed, 02 Dec 2009 11:37:55 -0600 Subject: [willamette-fcst] Forecast - Wednesday, December 2nd, 2009 Message-ID: Daily Smoke Management Forecast Oregon Department of Agriculture Smoke Management Program Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts. Issued: Wednesday, December 2nd, 2009 at 9:00am. Burn Advisory: Agricultural burning is allowed. Suggested burn times are from 10:00am until 2:30pm. Stack burning is not allowed. Weather Discussion: An upper-level ridge of high pressure, centered just offshore, is producing a dry northerly flow aloft over Washington and Oregon. The air aloft is still very warm over western Oregon. The freezing levels, over Salem and Medford, were measured at 9500 feet and 11,000 feet respectively early this morning. Meanwhile, cool and dry low-level air is filtering southward, across the Willamette Valley. Strong low-level temperature inversions are still in place, but ventilation near the Columbia Gorge has significantly improved due to an increase in easterly winds...gusting to over 30 mph. Northerly winds in the central and southern Willamette Valley are not conducive to good ventilation for stack burning. The cool and dry low-level air helped to keep skies clear of fog in the northern Willamette Valley overnight, but there were still some areas of fog in the south valley this morning. Skies were sunny along the coast and over the Cascades. Temperatures were much cooler this morning, with most of the Willamette Valley dropping to near or below freezing. Mid-morning temperatures ranged from the mid 20s in the south valley to the mid 30s in the north valley. The ODA surface analysis showed pressures rising across eastern Washington and north-central Oregon, in response to the cool and dry Canadian air spilling into the region. A weak thermal torugh was also trying to build along the southern Oregon Coast. The offshore flow will promote further drying of the air mass across western Oregon. Fog should begin to lift, from the southern Willamette Valley this afternoon. Highs this afternoon will likely stay in the 40s in the south valley but may reach the low 50s in parts of the north valley and along the coast. Surface Winds: N 5-15 this morning, NNE 5-15 this afternoon. Transport Winds: N 10 this morning, NNE 10 this afternoon. Atmospheric Ventilation Conditions: Maximum mixing height today will be near 2000 feet. Ventilation index 20. High Temperature: Salem\'s high temperature today will be near 49. Humidities: Minimum relative humidity will be near 40%. Sunrise/Sunset: Salem sunset tonight: 4:32pm; sunrise tomorrow: 7:32am. Extended Outlook: The upper-level ridge is forecast to hold over the region Thursday, with another frosty morning and dry offshore flow providing plenty of afternoon sunshine to most of western Oregon. There may still be a few pockets of fog in the southern Willamette Valley and the southwestern valleys. Overnight temperatures will likely cool slightly, as the air mass continues to dry out, but daytime highs should recover close to normal. A cool weather system is forecast to move from southwestern Canada into Washington and northern Oregon by late Friday. This cold front may be strong enough to bring some light rain and snow to the region, with snow levels dropping to 1000 feet, or lower, by Saturday morning. Much colder air is forecast to push southward into Washington and Oregon over the weekend, but the air mass is forecast to remain mostly dry during the transition into the Arctic air. Quite cold and dry conditions will likely persist through early next week. A westerly flow aloft is forecast to undercut the offshore ridge and begin a warming trend around the middle of next week. That process will need to be closely monitored, for the potential of significant snow and/or ice accumulation, even in the Willamette Valley, as Pacific moisture gets thrown over the existing cold dome of low-level air. Temperatures will likely warm above freezing, in the lowest elevations, by the end of next week, with snow and ice turning to plain old rain in the lowlands. Significant snows may continue in the mountains. Tomorrow (03 Dec): Areas of AM Fog South. Mostly Sunny. NNE Winds. 26/46 Fri (04 Dec): Increasing Clouds. Slight Chance of Light Rain or Flurries Late. 26/45 Sat (05 Dec): Slight Chance of Light Rain or Snow Flurries. 30/44 Sun (06 Dec): Partly Cloudy and Cold. Slight Chance of Light Snow. 26/35 Mon (07 Dec): Sunny and Cold. 22/33 Tue (08 Dec): Sunny and Cold. 20/35 Wed (09 Dec): Good Chance of Snow. Significant Accumulations Possible. 25/33 ODA Meteorologist weather at oda.state.or.us From willamette-fcst at listsmart.osl.state.or.us Thu Dec 3 10:01:44 2009 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Thu, 03 Dec 2009 12:01:44 -0600 Subject: [willamette-fcst] Forecast - Thursday, December 3rd, 2009 Message-ID: Daily Smoke Management Forecast Oregon Department of Agriculture Smoke Management Program Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts. Issued: Thursday, December 3rd, 2009 at 9:00am. Burn Advisory: Agricultural burning is allowed. Suggested burn times are from 11:00am until 2:00pm. Stack burning is not allowed. Weather Discussion: An upper-level ridge of high pressure, centered just offshore, is producing a dry northerly flow aloft over Washington and Oregon today. The air aloft is still very warm over western Oregon, with freezing levels around 10,000 feet. However, cool and dry low-level air has filtered southward, across the Willamette Valley. That is maintaining a strong low-level temperature inversion over the valley. It was cold again this morning across the state with Willamette Valley minimums mostly in the 20s and low 30s. There were pockets of icy fog in the south valley, with visibilities less than one-quarter of a mile in the Eugene area. In contrast, the the central and north valley were free of fog but getting some increase in high clouds from a weak weather system movning into southwestern British Columbia. The ODA surface analysis showed pressures continuing to rise across eastern Washington and north-central Oregon, in response to the cool and dry Canadian air spilling into the region. That was combining with a weak thermal trough along the southern Oregon Coast to bring a dry offshore flow to western Oregon. Easterly winds were gusting as high as 30 mph along the central Oregon Coast and to over 40 mph at the western end of the Columbia Gorge. The few patches of fog in the southern Willamette Valley should give way to increasing high clouds this afternoon. Highs this afternoon will likely stay in the mid 40s in the south valley but may reach the low 50s in parts of the north valley and along the coast. Surface Winds: N 5-10 this morning, N 5-10 this afternoon. Transport Winds: N 10 this morning, N 10 this afternoon. Atmospheric Ventilation Conditions: Maximum mixing height today will be near 2000 feet. Ventilation index 20. High Temperature: Salem\'s high temperature today will be near 50. Humidities: Minimum relative humidity will be near 33%. Sunrise/Sunset: Salem sunset tonight: 4:32pm; sunrise tomorrow: 7:34am. Extended Outlook: A cool weather system is forecast to drop southward, across Washington and northern Oregon, late on Friday. It will have very limited moisture but will bring a chance of spotty light rain and snow to the region. Snow levels will rapidly drop to around 1000 feet, or lower, Saturday. An Arctic cold front is forecast to push southward across Washington and Oregon Saturday night and Sunday. That system is associated with very cold air but limited moisture. It should produce lots of clouds, and at least some snow flurries, as it pushes southward across the Willamette Valley Saturday night into Sunday morning. It is possible that some valley locations could pick up enough snow to cover the ground, but significant accumulations are unlikely. Quite cold and dry conditions will follow the Arctic cold frontal passage later Sunday through Tuesday. Cold easterly winds will increase in and near the Columbia River Gorge, making for very low windchill values. Overnight minimums will drop well into the 20s, across the Willamette Valley, Monday and Tuesday (locally into the high teens). Mostly sunny skies will help daytime highs recover into the 30s. A westerly flow aloft is forecast to undercut the offshore ridge and begin introducing moisture into western Oregon next Wednesday. With cold air in place across western Oregon, there is a high potential for significant snow and/or ice accumulation Wednesday and Thursday, before warmer Pacific air can penetrate inland. Temperatures will eventually moderate above freezing, from south to north across the Willamette Valley...most likely on Thursday. The last place to transition back to plain old rain will be areas in and near the Columbia River Gorge. Snow levels should lift to 4-5000 feet by Friday, with precipitation in the Gorge finally changing to all rain. Tomorrow (04 Dec): Increasing Clouds. Slight Chance of Light Rain or Flurries Late. 26/45 Sat (05 Dec): Partly Cloudy. Increasing Clouds with Snow Flurries Late. 28/44 Sun (06 Dec): Chance of Light Snow Early. Turning Partly Cloudy and Cold. 27/35 Mon (07 Dec): Sunny and Cold. 20/33 Tue (08 Dec): Sunny and Cold. 21/35 Wed (09 Dec): Snow Developing Late. Possibly Turning to Freezing Rain or Rain South. 22/34 Thu (10 Dec): Snow, Freezing Rain, or Rain...Turning to Rain From South to North. 32/44 ODA Meteorologist weather at oda.state.or.us From willamette-fcst at listsmart.osl.state.or.us Fri Dec 4 09:08:05 2009 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Fri, 04 Dec 2009 11:08:05 -0600 Subject: [willamette-fcst] Forecast - Friday, December 4th, 2009 Message-ID: Daily Smoke Management Forecast Oregon Department of Agriculture Smoke Management Program Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts. Issued: Friday, December 4th, 2009 at 9:00am. Burn Advisory: Agricultural burning is allowed. Suggested burn times are from 12:00pm until 2:30pm. Stack burning is not allowed. Weather Discussion: A dry and cool northwesterly flow aloft is directing a an upper-level disturbance southward across southern British Columbia this morning. Satellite imagery shows very limited moisture with this system, but it was pushing some low clouds onto the northern Oregon Coast. The remainder of Oregon had mostly sunny skies this morning, with the expection of areas of icy valley fog. Enough cold and dry low-level air has filtered into the Willamette Valley to inhibit fog formation, except for in the extreme south valley. It was cold again this morning, with mid-morning temperatures in the 20s and low 30s across western Oregon. The ODA surface analysis showed weak pressure gradients across the region and winds were generally light. A cool weather system is forecast to drop southward, across Washington and northern Oregon, later today and tonight. It will have very limited moisture but will bring a chance of spotty light rain and snow to the region. Snow levels will rapidly drop to around 1000 feet, or lower, Saturday. Surface Winds: Var 0-6 this morning, NNW 5-10 this afternoon. Transport Winds: Var 3 this morning, NW 7 this afternoon. Atmospheric Ventilation Conditions: Maximum mixing height today will be near 1700 feet. Ventilation index 12. High Temperature: Salem\'s high temperature today will be near 45. Humidities: Minimum relative humidity will be near 50%. Sunrise/Sunset: Salem sunset tonight: 4:31pm; sunrise tomorrow: 7:35am. Extended Outlook: An Arctic cold front will be driven southward, across Washington and Oregon, Saturday night and Sunday, by a strong northerly flow aloft. This front will not have a lot of moisture to work with but may produce some flurries or a dusting of snow across the lowlands of western Oregon...including the coastline. Quite cold and dry conditions will follow the Arctic cold frontal passage later Sunday and Monday. Weak impulses, in the cold northerly flow, may bring some flurries to western Oregon Tuesday and Wednesday, along with reinforcing surges of cold air. Cold easterly winds will increase, in and near the Columbia River Gorge, beginning this weekend, making for very low windchill values. Morning minimums will drop into the teens and 20s across the Willamette Valley, Monday and Tuesday, with highs likely staying at or below freezing, even with some sunshine. A westerly flow aloft is forecast to undercut the offshore ridge and begin introducing moisture into California by next Wednesday. Some moisture may extend northward, into Oregon, by Thursday, but that is questionable. It now appears as if the mostly dry northerly flow will dominate through most of next week...decreasing the threat of significant snow but keeping temperatures frigid. Some moderation in temperatures will likely begin by Friday, but no significant moisture is forecast to be directed into the region. Tomorrow (05 Dec): Partly Cloudy. Increasing Clouds with Snow Flurries Late. 28/44 Sun (06 Dec): Chance of Light Snow Early. Turning Partly Cloudy and Cold. 27/31 Mon (07 Dec): Partly Cloudy and Much Colder. Chance of Flurries. 19/30 Tue (08 Dec): Partly Cloudy and Cold. Chance of Flurries. 17/31 Wed (09 Dec): Partly Cloudy and Cold. Chance of Flurries. 17/31 Thu (10 Dec): Partly Cloudy and Cold. Chance of Flurries. 18/32 Fri (11 Dec): Partly Cloudy and Cold. Chance of Flurries. 22/35 ODA Meteorologist weather at oda.state.or.us From willamette-fcst at listsmart.osl.state.or.us Mon Dec 7 09:14:11 2009 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Mon, 07 Dec 2009 11:14:11 -0600 Subject: [willamette-fcst] Forecast - Monday, December 7th, 2009 Message-ID: Daily Smoke Management Forecast Oregon Department of Agriculture Smoke Management Program Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts. Issued: Monday, December 7th, 2009 at 9:00am. Burn Advisory: Agricultural burning is allowed. Suggested burn times are from 9:00am until 2:30pm. Straw stack burning is allowed from 9:00am until 2:30pm. Weather Discussion: A strong northerly flow aloft drove a cold and dry Arctic air mass into Oregon over the weekend. The morning ODA surface analysis showed a cold dome of high pressure centered over central and eastern Washington, with strong northerly flow across central and eastern Oregon and offshore flow across western Oregon. The combination of brisk north-northeasterly winds, gusting to near 30 mph, and surface temperatures in the mid 20s dropped windchill values into the single digits in the northern Willamette Valley overnght. Northerly winds of 10-15 mph were common in the central and southern Willamette Valley this morning, with temperatures in the low to mid 20s. Visible satellite imagery showed low clouds, due to upsloping northeasterly winds, covering sections of central Oregon. A few middle and high clouds were streaming across the Willamette Valley, but the low-levels of the atmosphere were very dry west of the Cascades. Cold air also moved in aloft over the weekend, with the freezing level crashing from around 10,000 feet to the surface. Temperatures were near zero this morning over the Cascade passes, with brisk easterly winds making for dangerously cold windchill temperatures. The cold and dry offshore flow extended to the coastline. Temperatures along the beaches were in the mid to upper 20s this morning, with brisk easterly winds dropping windchill temperatures to around 10 degrees. Temperatures were in the single digits over most of central and eastern Oregon, at mid-morning. Meacham, in the northeast mountains, was a chilly 5 degrees below zero. The upper-level trough that ushered the cold air into the region has moved south of Oregon and will bring rain and snow to much of central and southern California today. Dry notherly flow aloft will presist over Oregon, with temperatures staying below freezing all day, except for along the southern coast and sections of the interior of southwestern Oregon. Even with plenty of sunshine, highs in the Willamette Valley will struggle to reach 30 degrees, with continued brisk north-northeasterly winds. Mostly clear skies tonight will allow temperatures to quickly fall into the teens and possibly the single digits, in wind-sheltered areas. Surface Winds: NNE 10-15 G30 North this morning, NNE 10-15 G 30 North this afternoon. Transport Winds: NE 15 this morning, NE 15 this afternoon. Atmospheric Ventilation Conditions: Maximum mixing height today will be near 2500 feet. Ventilation index 38. High Temperature: Salem\'s high temperature today will be near 30. Humidities: Minimum relative humidity will be near 27%. Sunrise/Sunset: Salem sunset tonight: 4:31pm; sunrise tomorrow: 7:38am. Extended Outlook: A weak upper-level disturbance, in the cold northerly flow aloft, is forecast to drop southward, from British Columbia to just off the Oregon Coast Tuesday. It may gather enough moisture to spread some clouds across western Oregon, with a treat of snow flurries, especially along the coast and over the coast range. Offshore pressure gradients should relax slightly, with some decrease in the north-northeasterly winds across western Oregon. After a very cold start, afternoon temperatures will, once again, struggle to reach 30 degrees in the Willamette Valley. Cold and generally dry notherly flow aloft will continue Wednesday and Thursday, with only a slight moderation of temperatures. By Friday, a westerly flow aloft will begin to undercut the offshore ridge and inject Pacific moisture into the cold dome of air over western Oregon. That will increase the chance of snow or freezing rain, with moderating temperatures. Things could get pretty messy, especially in the northern Willamette Valley, before an eventual changeover to plain old rain early next week...if not sooner. Tomorrow (08 Dec): Partly Cloudy. Slight Chance of Snow Flurries. 13/28 Wed (09 Dec): Partly Cloudy. Slight Chance of Snow Flurries. 14/30 Thu (10 Dec): Mostly Sunny and Continue Cold. 17/32 Fri (11 Dec): Increasing Chance of Snow or Freezing Rain. 22/32 Sat (12 Dec): Snow, Sleet, Freezing Rain, or Rain Likely. 28/35 Sun (13 Dec): Snow, Sleet, Freezing Rain or Rain Likely. 30/37 Mon (14 Dec): Chance of Snow, Sleet, Freezing Rain or Rain. 30/37 ODA Meteorologist weather at oda.state.or.us From willamette-fcst at listsmart.osl.state.or.us Mon Dec 7 12:12:04 2009 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Mon, 07 Dec 2009 14:12:04 -0600 Subject: [willamette-fcst] Forecast - Monday, December 7th, 2009 Message-ID: Daily Smoke Management Forecast Oregon Department of Agriculture Smoke Management Program Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts. Issued: Monday, December 7th, 2009 at 9:00am. Burn Advisory: Agricultural burning is allowed. Suggested burn times are from 9:00am until 2:30pm. Straw stack burning is allowed from 9:00am until 2:30pm. Weather Discussion: A strong northerly flow aloft drove a cold and dry Arctic air mass into Oregon over the weekend. The morning ODA surface analysis showed a cold dome of high pressure centered over central and eastern Washington, with strong northerly flow across central and eastern Oregon and offshore flow across western Oregon. The combination of brisk north-northeasterly winds, gusting to near 30 mph, and surface temperatures in the mid 20s dropped windchill values into the single digits in the northern Willamette Valley overnght. Northerly winds of 10-15 mph were common in the central and southern Willamette Valley this morning, with temperatures in the low to mid 20s. Visible satellite imagery showed low clouds, due to upsloping northeasterly winds, covering sections of central Oregon. A few middle and high clouds were streaming across the Willamette Valley, but the low-levels of the atmosphere were very dry west of the Cascades. Cold air also moved in aloft over the weekend, with the freezing level crashing from around 10,000 feet to the surface. Temperatures were near zero this morning over the Cascade passes, with brisk easterly winds making for dangerously cold windchill temperatures. The cold and dry offshore flow extended to the coastline. Temperatures along the beaches were in the mid to upper 20s this morning, with brisk easterly winds dropping windchill temperatures to around 10 degrees. Temperatures were in the single digits over most of central and eastern Oregon, at mid-morning. Meacham, in the northeast mountains, was a chilly 5 degrees below zero. The upper-level trough that ushered the cold air into the region has moved south of Oregon and will bring rain and snow to much of central and southern California today. Dry notherly flow aloft will presist over Oregon, with temperatures staying below freezing all day, except for along the southern coast and sections of the interior of southwestern Oregon. Even with plenty of sunshine, highs in the Willamette Valley will struggle to reach 30 degrees, with continued brisk north-northeasterly winds. Mostly clear skies tonight will allow temperatures to quickly fall into the teens and possibly the single digits, in wind-sheltered areas. Surface Winds: NNE 10-15 G30 North this morning, NNE 10-15 G 30 North this afternoon. Transport Winds: NE 15 this morning, NE 15 this afternoon. Atmospheric Ventilation Conditions: Maximum mixing height today will be near 2500 feet. Ventilation index 38. High Temperature: Salem\'s high temperature today will be near 30. Humidities: Minimum relative humidity will be near 27%. Sunrise/Sunset: Salem sunset tonight: 4:31pm; sunrise tomorrow: 7:38am. Extended Outlook: A weak upper-level disturbance, in the cold northerly flow aloft, is forecast to drop southward, from British Columbia to just off the Oregon Coast Tuesday. It may gather enough moisture to spread some clouds across western Oregon, with a treat of snow flurries, especially along the coast and over the coast range. Offshore pressure gradients should relax slightly, with some decrease in the north-northeasterly winds across western Oregon. After a very cold start, afternoon temperatures will, once again, struggle to reach 30 degrees in the Willamette Valley. Cold and generally dry notherly flow aloft will continue Wednesday and Thursday, with only a slight moderation of temperatures. By Friday, a westerly flow aloft will begin to undercut the offshore ridge and inject Pacific moisture into the cold dome of air over western Oregon. That will increase the chance of snow or freezing rain, with moderating temperatures. Things could get pretty messy, especially in the northern Willamette Valley, before an eventual changeover to plain old rain early next week...if not sooner. Tomorrow (08 Dec): Partly Cloudy. Slight Chance of Snow Flurries. 13/28 Wed (09 Dec): Partly Cloudy. Slight Chance of Snow Flurries. 14/30 Thu (10 Dec): Mostly Sunny and Continue Cold. 17/32 Fri (11 Dec): Increasing Chance of Snow or Freezing Rain. 22/32 Sat (12 Dec): Snow, Sleet, Freezing Rain, or Rain Likely. 28/35 Sun (13 Dec): Snow, Sleet, Freezing Rain or Rain Likely. 30/37 Mon (14 Dec): Chance of Snow, Sleet, Freezing Rain or Rain. 30/37 ODA Meteorologist weather at oda.state.or.us From willamette-fcst at listsmart.osl.state.or.us Tue Dec 8 09:11:38 2009 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Tue, 08 Dec 2009 11:11:38 -0600 Subject: [willamette-fcst] Forecast - Tuesday, December 8th, 2009 Message-ID: Daily Smoke Management Forecast Oregon Department of Agriculture Smoke Management Program Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts. Issued: Tuesday, December 8th, 2009 at 9:00am. Burn Advisory: Agricultural burning is allowed. Suggested burn times are from 12:00pm until 2:30pm. Stack burning is not allowed. Weather Discussion: A weak upper-level disturbance, in the cold northerly flow aloft, will drop southward, from British Columbia to just off the Oregon Coast this afternoon. It does not appear as if it will have enough moisture to bring any precipitation to the region, so skies should stay mostly sunny over western Oregon. There will be some middle and high clouds, mainly near the coast. Offshore pressure gradients should relax slightly today, with some decrease in the north-northeasterly winds across western Oregon. After a very cold start, with western Oregon temperatures mostly in the teens, afternoon highs will struggle to around the freezing mark in the Willamette Valley. I\'ll have a rundown of the cold morning minimums on the noon update. Surface Winds: NNE 5-15 this morning, NNE 5-15 this afternoon. Transport Winds: NNE 10 this morning, NNE 10 this afternoon. Atmospheric Ventilation Conditions: Maximum mixing height today will be near 2700 feet. Ventilation index 27. High Temperature: Salem\'s high temperature today will be near 29. Humidities: Minimum relative humidity will be near 30%. Sunrise/Sunset: Salem sunset tonight: 4:31pm; sunrise tomorrow: 7:39am. Extended Outlook: Cold and dry northerly flow aloft will continue Wednesday and Thursday. Decreasing surface winds will allow for even colder overnight temperatures across western Oregon. Mostly sunny skies will help afternoon highs recover to around freezing. By Friday, a westerly flow aloft will begin to undercut the offshore ridge...taking Pacific storm systems into California. The flow aloft over Oregon will back from northerly to northwesterly. Clouds will be on the increase across extreme southern Oregon, but skies should remain mostly sunny over the Willamette Valley with moderating temperatures. By Saturday morning, moisture is forecast to spread northward into the Willamette Valley. The air mass aloft will be warming, but continued offshore flow at the surface should allow enough low-level cold air to remain in place for precipitation to fall mainly as snow, sleet, or freezing rain. there may be enough warming for areas of the central and southern valley to changeover to plain old rain, but expect conditions to remain icy in the Portland area and in the Columbia Gorge. By Sunday, most of the Willamette Valley should see temperatures moderate to above freezing, with precipitation falling as rain. However, there may still be areas of wintry precipitation in and near the Columbia Gorge. A much warmer weather system is forecast to come onshore late Monday, which should scour out any remaining low-level cold air trapped in the Gorge. Tomorrow (09 Dec): Mostly Sunny and Cold. 11/30 Thu (10 Dec): Mostly Sunny and Cold. 15/34 Fri (11 Dec): Mostly Sunny and Cold. 19/38 Sat (12 Dec): Snow, Sleet, or Freezing Rain Likely. Likley Changing to Rain South. 28/35 Sun (13 Dec): Chance of Rain...Possible Wintry Mix Near the Gorge. 32/42 Mon (14 Dec): Rain Increasing Late. Turning Warmer. 36/50 Tue (15 Dec): Rain Likely. Mild. 42/52 ODA Meteorologist weather at oda.state.or.us From willamette-fcst at listsmart.osl.state.or.us Tue Dec 8 12:09:06 2009 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Tue, 08 Dec 2009 14:09:06 -0600 Subject: [willamette-fcst] Forecast - Tuesday, December 8th, 2009 Message-ID: Daily Smoke Management Forecast Oregon Department of Agriculture Smoke Management Program Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts. ...Next Update Not Until Thursday, December 10th, 2009 at 9:00am... Issued: Tuesday, December 8th, 2009 at 12:00pm. Burn Advisory: Agricultural burning is allowed. Suggested burn times are from now until 2:30pm. Stack burning is not allowed. Weather Discussion: Washington and Oregon remain under the influence of a dry and cold northerly flow aloft today, with a low-level dome of cold Arctic air blanketing the region. A weak upper-level disturbance was visible on satellite imagery dropping southward just off the Washington Coast late this morning. Cloudiness associated with this system was staying offshore, with dry north-northeasterly winds keeping skies sunny across western Washington and western Oregon. Although some increase in middle high clouds is is possible along the Oregon Coast, later today, it does not appear as if any precipitation will move onshore. Offshore pressure gradients haved relaxed since Monday, with north-northeasterly winds generally in the 5-15 mph range across western Oregon. The exception was in the extreme northern Willamette Valley, where outflow from the Columbia Gorge was generating easterly gusts to around 25 mph. It was the coldest morning of the year across most of the state. Many spots east of the Cascades fell well below zero. Meacham (northeastern Oregon) was the cold spot in the state this morning at -14 degrees. Burns (southeastern Oregon) dropped down to -12 degrees, Lakeview (south-central Oregon) hit -11, and Redmond (central Oregon) dipped to -10 degrees. Most of western Oregon dropped into the teens overnight. Eugene bottomed out at just 10 degrees. Hillsboro dipped down to 12, and Corvallis slid to 13. Both Portland and Salem recorded a minimum of 14 degrees. With sunny skies today, afternoon highs will struggle to around the freezing mark in the Willamette Valley. Temperatures will quickly drop back into the teens, under mostly clear skies, this evening. Surface Winds: NNE 5-15 this afternoon. Transport Winds: NNE 10 this afternoon. Atmospheric Ventilation Conditions: Maximum mixing height today will be near 2700 feet. Ventilation index 27. High Temperature: Salem\'s high temperature today will be near 30. Humidities: Minimum relative humidity will be near 25%. Sunrise/Sunset: Salem sunset tonight: 4:31pm; sunrise tomorrow: 7:39am. Extended Outlook: Cold and dry northerly flow aloft will continue Wednesday and Thursday. Decreasing surface winds will allow for even colder overnight temperatures across western Oregon, single-digit readings likely in sections of the Willamette Valley. Sunny skies will help afternoon highs recover to around freezing on Wednesday and possibly the mid 30s on Thursday. By Friday, a westerly flow aloft will begin to undercut the offshore ridge...directing Pacific moisture into California. The flow aloft over Oregon will back from northerly to northwesterly, with clouds increasing across extreme southern Oregon. Skies should remain mostly sunny over the Willamette Valley with highs climbing in the mid to upper 30s. By Saturday morning, moisture is forecast to spread northward into the Willamette Valley. The air mass aloft will be warming, but continued offshore flow at the surface should allow enough low-level cold air to remain in place for precipitation to begin as snow, sleet, or freezing rain. There will likely be enough warming for much of the central and southern valley to changeover to plain old rain by late Saturday, but expect wintry conditions to hold fast in the Portland area and in the Columbia Gorge. Precipitation is expected to taper off Sunday, with most of the Willamette Valley just getting plain old rain. However, there could still be enough cold air coming out of the Columbia Gorge to keep wintry precipitation in the immediate Portland area. A much warmer weather system is forecast to come onshore late Monday, which should scour out the remaining low-level cold air trapped in the Gorge. Tomorrow (09 Dec): Mostly Sunny and Cold. 11/32 Thu (10 Dec): Mostly Sunny and Cold. 15/34 Fri (11 Dec): Mostly Sunny and Cold. 19/38 Sat (12 Dec): Snow, Sleet, or Freezing Rain...Likely Changing to Rain South. 28/35 Sun (13 Dec): Chance of Rain...Possible Wintry Mix Near the Gorge. 32/42 Mon (14 Dec): Rain Increasing Late. Turning Warmer. 36/50 Tue (15 Dec): Rain Likely. Mild. 42/52 ODA Meteorologist weather at oda.state.or.us From willamette-fcst at listsmart.osl.state.or.us Thu Dec 10 09:15:34 2009 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Thu, 10 Dec 2009 11:15:34 -0600 Subject: [willamette-fcst] Forecast - Thursday, December 10th, 2009 Message-ID: Daily Smoke Management Forecast Oregon Department of Agriculture Smoke Management Program Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts. Issued: Thursday, December 10th, 2009 at 9:00am. Burn Advisory: Agricultural burning is not recommended. Stack burning is not allowed. Weather Discussion: A very cold and dry air mass will remain in place over Washington and Oregon today. With the exception of a few mid and high-level clouds, satellite imagery and surface reports show mostly clear skies over both states. The ODA surface analysis showed high pressure centered near the eastern end of the Columbia Gorge, with continued weak offshore flow across western Oregon. Light winds and clear skies allowed temperatures to locally drop into the single digits across the Willamette Valley early this morning. Even the southwestern valleys dropped well down into the teens, with coastal minimums mostly in the low 20s. The very cold northerly jet stream, that brought the Arctic air into the region, is slowly shifting east...allowing temperatures aloft to begin warming. The Salem sounding from early this morning showed several degrees of warming, between 2000 feet and 16,000 feet. A strengthening low-level temperature inversion is is making for poor ventilation conditions. Even though the air mass aloft is warming, temperatures were still below freezing. Another full day of sunshine is expected today, but the shortened day and low sun-angle will not allow for enough surface warming to break the strong low-level temperature inversion. Valley highs, once again, will struggle to get to the freezing mark. Winds will remain light from the north-northeast, except for near the western end of the Columbia Gorge, where easterly winds will gust to around 30 mph...making for very cold windchill temperatures. Surface Winds: NNE 0-6 this morning, NNE 3-8 this afternoon. Transport Winds: NNE 6 this morning, NNE 6 this afternoon. Atmospheric Ventilation Conditions: Maximum mixing height today will be near 1700 feet. Ventilation index 10. High Temperature: Salem\'s high temperature today will be near 31. Humidities: Minimum relative humidity will be near 40%. Sunrise/Sunset: Salem sunset tonight: 4:31pm; sunrise tomorrow: 7:40am. Extended Outlook: Skies should remain mostly clear overnight across the Willamette Valley, making for very cold temperatures, again, Friday morning. However, some changes will begin to show up by Friday afternoon. The flow aloft over Oregon will turn westerly, with clouds increasing across southern Oregon, as a Pacific weather system moves into California. Clouds will begin to increase, from the south, across the Willamette Valley, Friday afternoon and evening. Continued north-northeastery surface winds will maintain the cold layer of air, below about 2000 feet, while the upper-levels of the atmosphere warm above freezing. That will set the stage for a wintry mix of precipitation Friday night and Saturday... By early Saturday morning, enough moisture is forecast to spread northward into the Willamette Valley for precipitation to begin. The air mass aloft will be continuing to warm, but low-level cold air will reamin entrenched across the Willamette Valley. The cold air mass will be deepest in the north valley, where precipitation will likely begin as all snow. However,the air aloft over the central and south valley will be warmer, so some sleet and/or freezing rain is likely to at least mix with snow. Precipitation amounts are not forecast to be heavy, with most of the moisture staying south of the region. However, even small amounts of freezing rain can make for very hazardous travel conditions. Precipitation is expected to taper off Sunday, with the low-level flow turning weakly onshore. That should help most of the Willamette Valley transition to just plain rain. However, there could still be enough cold air coming out of the Columbia Gorge to keep wintry precipitation in the immediate Portland area. Another weather system is forecast to come onshore late Monday. There could still be enough cold air remaining in the Columbia Gorge, and the immediate Portland area, for a wintry mix of precipitation, but the rest of the Willamette Valley should get just rain. Even the Gorge should get scoured out by Tuesday, with warmer Pacific air moving back into the region. Tomorrow (11 Dec): Mostly Sunny and Cold Early. Increasing Clouds. 15/34 Sat (12 Dec): Snow, Sleet, or Freezing Rain...Likely Changing to Rain South. 28/35 Sun (13 Dec): Showers...Possible Wintry Mix Near the Gorge. 32/42 Mon (14 Dec): Mostly Cloudy. Chance of Rain...Possible Freezing Rain North. 32/40 Tue (15 Dec): Rain. Possibly Starting as Freezing Rain North. 32/47 Wed (16 Dec): Mostly Cloudy and Warmer. Rain Likely Late. 37/49 Thu (17 Dec): Rain Turning to Showers. 42/49 ODA Meteorologist weather at oda.state.or.us From willamette-fcst at listsmart.osl.state.or.us Thu Dec 10 12:10:06 2009 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Thu, 10 Dec 2009 14:10:06 -0600 Subject: [willamette-fcst] Forecast - Thursday, December 10th, 2009 Message-ID: Daily Smoke Management Forecast Oregon Department of Agriculture Smoke Management Program Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts. Issued: Thursday, December 10th, 2009 at 12:00pm. Burn Advisory: Agricultural burning is not recommended. Stack burning is not allowed. Weather Discussion: A very cold and dry air mass remains in place over Washington and Oregon today. Satellite imagery and surface reports show mostly clear skies over both states. Light winds and clear skies allowed temperatures to locally drop into the single digits across the Willamette Valley early this morning. Eugene and Hillsboro both dropped to 8 degrees (after recording minimums of 7 degrees Wednesday morning), Salem and Corvallis both bottomed out at 10 degrees, for the second consecutive morning, and Portland hit 13 degrees (Wednesday\'s low in Portland was 12 degrees). Even the southwestern valleys dropped well down into the teens. Medford recorded a minimum this morning of just 12 degrees and Roseburg dropped to 14. The Arctic chill extended to the beaches. Astoria had a morning minimum 20 degrees (Wednesday\'s low was 15 degrees), North Bend dropped to 23 degrees (Wednesday\'s low was 19 degrees). As expected, the coldest temperatures in the state were east of the Cascades. Many location were below zero this morning. Redmond dropped to -10 degrees...the third straight day with a double-digit below zero minimum. Pendleton also dipped below zero with a minimum of -1. Sunny skies had helped warm midday temperatures into the mid to upper 20s across the interior valleys of western Oregon, with readings in the 30s along the coast. As a sign of things to come, Brookings, on the southern Oregon Coast, had warmed into the mid 40s. Midday temperatures were only in the teens and low 20s east of the Cascades...including in the Columbia Gorge. The ODA surface analysis showed high pressure centered near the eastern end of the Columbia Gorge, with offshore flow continuing across western Oregon. The very cold northerly jet stream, that brought the Arctic air into the region, is slowly shifting east...allowing warmer air to move in aloft over the region. The Salem sounding from early this morning showed several degrees of warming, between 2000 feet and 16,000 feet, but the entire column of air was still below freezing. A strong low-level temperature inversion is making for poor ventilation conditions. Another full day of sunshine is expected today, but the shortened day-length and low sun-angle will not generate enough surface warming to break the low-level temperature inversions. Valley highs, once again, will struggle to get to the freezing mark. Winds will remain light from the north-northeast, except for easterly gusts to around 30 mph near the western end of the Columbia Gorge...making for very cold windchill values. Surface Winds: NNE 3-8 this afternoon. Transport Winds: NNE 6 this afternoon. Atmospheric Ventilation Conditions: Maximum mixing height today will be near 1700 feet. Ventilation index 10. High Temperature: Salem\'s high temperature today will be near 31. Humidities: Minimum relative humidity will be near 40%. Sunrise/Sunset: Salem sunset tonight: 4:31pm; sunrise tomorrow: 7:40am. Extended Outlook: Skies should remain mostly clear overnight across the Willamette Valley, making for very cold temperatures. However, some changes will begin to show up on Friday. The flow aloft over Oregon will turn westerly, with a weather system undercutting the offshore ridge and moving into California. Clouds will increase, from south to north, across Oregon during the day. With surface low-pressure forecast to approach the northern California Coast, offshore gradients will continue to feed cold low-level air out of the Columbia Gorge and into the Willamette Valley. Meanwhile, the air mass above 2000 feet will continue to warm and should climb above freezing...especially over the central and southern Willamette Valley. That will set the stage for a wintry mix of precipitation later Friday through Saturday... Computer models differ considerably on both their timing and intensity of the precipitation across western Oregon. Some begin the wintry mix, in the southern Willamette Valley, as early as late Friday afternoon...pushing into the north valley Friday night. Others hold off on the precipitation until Friday night south and late-morning north. Forecast precipitation amounts vary from around one-tenth of an inch (water equivalent) to around four-tenths of an inch. Even small amounts of snow, sleet, and freezing rain can make for very hazardous travel conditions. Precipitation is expected to taper off Sunday, with the low-level flow turning weakly onshore across most of the valley. That should help most of the Willamette Valley transition to just plain rain. However, there could still be enough cold air coming out of the Columbia Gorge to keep wintry precipitation in the immediate Portland area. Another weather system is forecast to come onshore late Monday. There could still be enough cold air remaining in the Columbia Gorge, and the immediate Portland area, for a wintry mix of precipitation, but the rest of the Willamette Valley should get just rain. Even the Gorge should get scoured out by Tuesday, with warmer Pacific air moving back into the region. Tomorrow (11 Dec): Mostly Sunny and Cold Early. Increasing Clouds. 15/34 Sat (12 Dec): Snow, Sleet, or Freezing Rain...Likely Changing to Rain South. 28/35 Sun (13 Dec): Showers...Possible Wintry Mix Near the Gorge. 32/42 Mon (14 Dec): Mostly Cloudy. Chance of Rain...Possible Freezing Rain North. 32/40 Tue (15 Dec): Rain. Possibly Starting as Freezing Rain North. 32/47 Wed (16 Dec): Mostly Cloudy and Warmer. Rain Likely Late. 37/49 Thu (17 Dec): Rain Turning to Showers. 42/49 ODA Meteorologist weather at oda.state.or.us From willamette-fcst at listsmart.osl.state.or.us Fri Dec 11 09:12:05 2009 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Fri, 11 Dec 2009 11:12:05 -0600 Subject: [willamette-fcst] Forecast - Friday, December 11th, 2009 Message-ID: Daily Smoke Management Forecast Oregon Department of Agriculture Smoke Management Program Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts. Issued: Friday, December 11th, 2009 at 9:00am. Burn Advisory: Agricultural burning is not recommended. Stack burning is not allowed. Weather Discussion: A very cold and dry air mass remains entrenched across Washington and Oregon this morning. Clear skies allowed temperatures to drop into the teens, and locally single digits, in the Willamette Valley this morning, with most areas only a couple of degrees warmer than on Thursday morning. Skies also remained clear along the northern and central coast, with most morning temperatures dropping into the low to mid 20s and locally into the upper teens. Many areas east of the Cascades fell below zero again this morning. As expected, some significant changes in the weather pattern are taking place this morning. The flow aloft over Oregon has become westerly, with a weather system undercutting the offshore ridge of high pressure and moving into California. That has continued to warm the air aloft, between 2000 and 10,000 feet, with a shallow layer of above-freeezing air showing up on the morning soundings, over Salem and Medford, between 2000 and about 5000 feet. The column of above freezing air was thicker over Medford than over Salem. Temperatures were still well below freezing from the surface up to about 2000 feet over both locations. That will set the stage for a wintry mix of precipitation later today through Saturday, as the feed of moisture moves northward across western Oregon. Clouds spread northward, into southern Oregon, overnight, and Doppler radar was showing precipitation also spreading north of the California border at mid-morning. Rain was falling in Brookings, on the southern Oregon Coast, where temperatures had warmed into the upper 30s. Surface temperatures in the southwestern interior were still in the 20s, where the precipitation will fall in the form of a wintry mix as it spreads northward this morning. Computer models differ considerably on both their timing and intensity of the precipitation, as it moves northward, across western Oregon today. Some begin the wintry mix, in the southern Willamette Valley, as early as mid-afternoon, with precipitation likely moving into the south valley by this evening. The plume of moisture will sweep northward to the Portland area by about midnight. High temperatures today will, once again, struggle to climb into the low to mid 30s. Temperatures will rapidly chill back into the 20s, as soon as the sun sets or if precipitation begins. The precipitation will begin mostly as snow or sleet in the south valley, with a likely transition to sleet and freezing rain, as the air aloft continues to warm. Light northerly surface winds will continue to supply low-level cold air throughout the valley. However, there may be enough surface warming, in the south valley, to change precipitation to just plain rain as early as Saturday morning. Further north, precipitation will be more likely to begin as snow, due to the deeper layer of cold air, especially in the Portland area and in the Columbia Gorge. A transition to sleet and/or freezing rain is possible in the north valley during the day Saturday, with portions of the central valley possibly changing to plain rain. Forecast precipitation amounts vary from around one-tenth of an inch (water equivalent) to around four-tenths of an inch. However, even small amounts of snow, sleet, and freezing rain can make for very hazardous travel conditions, so be prepared for wintry travel conditions in the Willamette Valley tonight and Saturday. It is possible that the bands of precipitation will stall over the north valley Saturday, which could end up producing more significant amounts of snow and ice there. Surface Winds: NNE 0-6 this morning, NNE 3-6 this afternoon. Transport Winds: NNE 5 this morning, NNE 5 this afternoon. Atmospheric Ventilation Conditions: Maximum mixing height today will be near 1500 feet. Ventilation index 8. High Temperature: Salem\'s high temperature today will be near 34. Humidities: Minimum relative humidity will be near 51%. Sunrise/Sunset: Salem sunset tonight: 4:31pm; sunrise tomorrow: 7:41am. Extended Outlook: Precipitation is expected to taper off Sunday, with the low-level flow turning onshore across most of the valley. That should help most of the Willamette Valley transition to just plain rain. However, there could still be enough cold air coming out of the Columbia Gorge to keep wintry precipitation in the immediate Portland area. Another weather system is forecast to come onshore late Monday. There could still be enough cold air remaining in the Columbia Gorge, and the immediate Portland area, for a wintry mix of precipitation, but the rest of the Willamette Valley should get just rain. Even the Gorge should get scoured out by Tuesday, with warmer Pacific air moving back into the region. Tomorrow (12 Dec): Snow, Sleet, or Freezing Rain...Likely Changing to Rain South. 28/35 Sun (13 Dec): Showers...Possible Wintry Mix Near the Gorge. Snow above 1500 feet. 32/42 Mon (14 Dec): Mostly Cloudy. Chance of Rain...Possible Wintry Mix North. 32/40 Tue (15 Dec): Rain. Possibly Starting as Freezing Rain North. 32/47 Wed (16 Dec): Mostly Cloudy and Warmer. Rain Likely Late. 37/49 Thu (17 Dec): Rain Turning to Showers. 42/49 Fri (18 Dec): Mostly Cloudy. Chance of Rain. 38/48 ODA Meteorologist weather at oda.state.or.us From willamette-fcst at listsmart.osl.state.or.us Fri Dec 11 09:13:48 2009 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Fri, 11 Dec 2009 11:13:48 -0600 Subject: [willamette-fcst] Forecast - Friday, December 11th, 2009 Message-ID: Daily Smoke Management Forecast Oregon Department of Agriculture Smoke Management Program Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts. Issued: Friday, December 11th, 2009 at 9:00am. Burn Advisory: Agricultural burning is not recommended. Stack burning is not allowed. Weather Discussion: A very cold and dry air mass remains entrenched across Washington and Oregon this morning. Clear skies allowed temperatures to drop into the teens, and locally single digits, in the Willamette Valley this morning, with most areas only a couple of degrees warmer than on Thursday morning. Skies also remained clear along the northern and central coast, with most morning temperatures dropping into the low to mid 20s and locally into the upper teens. Many areas east of the Cascades fell below zero again this morning. As expected, some significant changes in the weather pattern are taking place this morning. The flow aloft over Oregon has become westerly, with a weather system undercutting the offshore ridge of high pressure and moving into California. That has continued to warm the air aloft, between 2000 and 10,000 feet, with a shallow layer of above-freeezing air showing up on the morning soundings, over Salem and Medford, between 2000 and about 5000 feet. The column of above freezing air was thicker over Medford than over Salem. Temperatures were still well below freezing from the surface up to about 2000 feet over both locations. That will set the stage for a wintry mix of precipitation later today through Saturday, as the feed of moisture moves northward across western Oregon. Clouds spread northward, into southern Oregon, overnight, and Doppler radar was showing precipitation also spreading north of the California border at mid-morning. Rain was falling in Brookings, on the southern Oregon Coast, where temperatures had warmed into the upper 30s. Surface temperatures in the southwestern interior were still in the 20s, where the precipitation will fall in the form of a wintry mix as it spreads northward this morning. Computer models differ considerably on both their timing and intensity of the precipitation, as it moves northward, across western Oregon today. Some begin the wintry mix, in the southern Willamette Valley, as early as mid-afternoon, with precipitation likely moving into the south valley by this evening. The plume of moisture will sweep northward to the Portland area by about midnight. High temperatures today will, once again, struggle to climb into the low to mid 30s. Temperatures will rapidly chill back into the 20s, as soon as the sun sets or if precipitation begins. The precipitation will begin mostly as snow or sleet in the south valley, with a likely transition to sleet and freezing rain, as the air aloft continues to warm. Light northerly surface winds will continue to supply low-level cold air throughout the valley. However, there may be enough surface warming, in the south valley, to change precipitation to just plain rain as early as Saturday morning. Further north, precipitation will be more likely to begin as snow, due to the deeper layer of cold air, especially in the Portland area and in the Columbia Gorge. A transition to sleet and/or freezing rain is possible in the north valley during the day Saturday, with portions of the central valley possibly changing to plain rain. Forecast precipitation amounts vary from around one-tenth of an inch (water equivalent) to around four-tenths of an inch. However, even small amounts of snow, sleet, and freezing rain can make for very hazardous travel conditions, so be prepared for wintry travel conditions in the Willamette Valley tonight and Saturday. It is possible that the bands of precipitation will stall over the north valley Saturday, which could end up producing more significant amounts of snow and ice there. Surface Winds: NNE 0-6 this morning, NNE 3-6 this afternoon. Transport Winds: NNE 5 this morning, NNE 5 this afternoon. Atmospheric Ventilation Conditions: Maximum mixing height today will be near 1500 feet. Ventilation index 8. High Temperature: Salem\'s high temperature today will be near 34. Humidities: Minimum relative humidity will be near 51%. Sunrise/Sunset: Salem sunset tonight: 4:31pm; sunrise tomorrow: 7:41am. Extended Outlook: Precipitation is expected to taper off Sunday, with the low-level flow turning onshore across most of the valley. That should help most of the Willamette Valley transition to just plain rain. However, there could still be enough cold air coming out of the Columbia Gorge to keep wintry precipitation in the immediate Portland area. Another weather system is forecast to come onshore late Monday. There could still be enough cold air remaining in the Columbia Gorge, and the immediate Portland area, for a wintry mix of precipitation, but the rest of the Willamette Valley should get just rain. Even the Gorge should get scoured out by Tuesday, with warmer Pacific air moving back into the region. Tomorrow (12 Dec): Snow, Sleet, or Freezing Rain...Likely Changing to Rain South. 28/35 Sun (13 Dec): Showers...Possible Wintry Mix Near the Gorge. Snow above 1500 feet. 32/42 Mon (14 Dec): Mostly Cloudy. Chance of Rain...Possible Wintry Mix North. 32/40 Tue (15 Dec): Rain. Possibly Starting as Freezing Rain North. 32/47 Wed (16 Dec): Mostly Cloudy and Warmer. Rain Likely Late. 37/49 Thu (17 Dec): Rain Turning to Showers. 42/49 Fri (18 Dec): Mostly Cloudy. Chance of Rain. 38/48 ODA Meteorologist weather at oda.state.or.us From willamette-fcst at listsmart.osl.state.or.us Fri Dec 11 09:55:15 2009 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Fri, 11 Dec 2009 09:55:15 -0800 Subject: [willamette-fcst] Willamette Valley Forecast Message-ID: Oregon Department of Agriculture Smoke Management Program Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts. Issued: Friday, December 11th, 2009 at 9:00am. Burn Advisory: Agricultural burning is not recommended. Stack burning is not allowed. Weather Discussion: A very cold and dry air mass remains entrenched across Washington and Oregon this morning. Clear skies allowed temperatures to drop into the teens, and locally single digits, in the Willamette Valley this morning, with most areas only a couple of degrees warmer than on Thursday morning. Skies also remained clear along the northern and central coast, with most morning temperatures dropping into the low to mid 20s and locally into the upper teens. Many areas east of the Cascades fell below zero again this morning. As expected, some significant changes in the weather pattern are taking place this morning. The flow aloft over Oregon has become westerly, with a weather system undercutting the offshore ridge of high pressure and moving into California. That has continued to warm the air aloft, between 2000 and 10,000 feet, with a shallow layer of above-freeezing air showing up on the morning soundings, over Salem and Medford, between 2000 and about 5000 feet. The column of above freezing air was thicker over Medford than over Salem. Temperatures were still well below freezing from the surface up to about 2000 feet over both locations. That will set the stage for a wintry mix of precipitation later today through Saturday, as the feed of moisture moves northward across western Oregon. Clouds spread northward, into southern Oregon, overnight, and Doppler radar was showing precipitation also spreading north of the California border at mid-morning. Rain was falling in Brookings, on the southern Oregon Coast, where temperatures had warmed into the upper 30s. Surface temperatures in the southwestern interior were still in the 20s, where the precipitation will fall in the form of a wintry mix as it spreads northward this morning. Computer models differ considerably on both their timing and intensity of the precipitation, as it moves northward, across western Oregon today. Some begin the wintry mix, in the southern Willamette Valley, as early as mid-afternoon, with precipitation likely moving into the south valley by this evening. The plume of moisture will sweep northward to the Portland area by about midnight. High temperatures today will, once again, struggle to climb into the low to mid 30s. Temperatures will rapidly chill back into the 20s, as soon as the sun sets or if precipitation begins. The precipitation will begin mostly as snow or sleet in the south valley, with a likely transition to sleet and freezing rain, as the air aloft continues to warm. Light northerly surface winds will continue to supply low-level cold air throughout the valley. However, there may be enough surface warming, in the south valley, to change precipitation to just plain rain as early as Saturday morning. Further north, precipitation will be more likely to begin as snow, due to the deeper layer of cold air, especially in the Portland area and in the Columbia Gorge. A transition to sleet and/or freezing rain is possible in the north valley during the day Saturday, with portions of the central valley possibly changing to plain rain. Forecast precipitation amounts vary from around one-tenth of an inch (water equivalent) to around four-tenths of an inch. However, even small amounts of snow, sleet, and freezing rain can make for very hazardous travel conditions, so be prepared for wintry travel conditions in the Willamette Valley tonight and Saturday. It is possible that the bands of precipitation will stall over the north valley Saturday, which could end up producing more significant amounts of snow and ice there. Surface Winds: NNE 0-6 this morning, NNE 3-6 this afternoon. Transport Winds: NNE 5 this morning, NNE 5 this afternoon. Atmospheric Ventilation Conditions: Maximum mixing height today will be near 1500 feet. Ventilation index 8. High Temperature: Salem's high temperature today will be near 34. Humidities: Minimum relative humidity will be near 51%. Sunrise/Sunset: Salem sunset tonight: 4:31pm; sunrise tomorrow: 7:41am. Extended Outlook: Precipitation is expected to taper off Sunday, with the low-level flow turning onshore across most of the valley. That should help most of the Willamette Valley transition to just plain rain. However, there could still be enough cold air coming out of the Columbia Gorge to keep wintry precipitation in the immediate Portland area. Another weather system is forecast to come onshore late Monday. There could still be enough cold air remaining in the Columbia Gorge, and the immediate Portland area, for a wintry mix of precipitation, but the rest of the Willamette Valley should get just rain. Even the Gorge should get scoured out by Tuesday, with warmer Pacific air moving back into the region. Tomorrow (12 Dec): Snow, Sleet, or Freezing Rain...Likely Changing to Rain South. 28/35 Sun (13 Dec): Showers...Possible Wintry Mix Near the Gorge. Snow above 1500 feet. 32/42 Mon (14 Dec): Mostly Cloudy. Chance of Rain...Possible Wintry Mix North. 32/40 Tue (15 Dec): Rain. Possibly Starting as Freezing Rain North. 32/47 Wed (16 Dec): Mostly Cloudy and Warmer. Rain Likely Late. 37/49 Thu (17 Dec): Rain Turning to Showers. 42/49 Fri (18 Dec): Mostly Cloudy. Chance of Rain. 38/48 ODA Meteorologist weather at oda.state.or.us From willamette-fcst at listsmart.osl.state.or.us Fri Dec 11 12:17:10 2009 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Fri, 11 Dec 2009 14:17:10 -0600 Subject: [willamette-fcst] Forecast - Friday, December 11th, 2009 Message-ID: Daily Smoke Management Forecast Oregon Department of Agriculture Smoke Management Program Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts. ...Next Update Not Until Wednesday, December 23rd, 2009... NOON UPDATE Issued: Friday, December 11th, 2009 at 12:00pm. Burn Advisory: Agricultural burning is not recommended. Stack burning is not allowed. Weather Discussion: The very cold and dry air mass that has been entrenched across Washington and Oregon will get replaced by a much more mild and moist Pafcific air mass over the next 2-4 days, but the process will likely bring at least some wintry precipitation to much of the region. Clear skies allowed temperatures to drop into the teens, or colder, in the Willamette Valley this morning. Hillsboro dipped to 8 degrees, with McMinnville and Corvallis dipping to 9. Eugene\'s minimum was 11, Salem bottomed out at 12, and Portland dropped down to 14 degrees. The cold temperatures extended to the northern and central coast. Astoria dropped down to 20 degrees this morning. Many areas east of the Cascades fell below zero again this morning. Burns was the cold spot in the state with a low of -8 and Redmond dropped to -3. As expected, some significant changes in the weather pattern are currently underway. The flow aloft over Oregon has become westerly, with a weather system undercutting the offshore ridge of high pressure and moving into California. Continued warming aloft has created a layer of above-freezing air above about 2000 feet over most of western Oregon. The column of above freezing is more thick over southern Oregon. Temperatures are still below freezing, from the surface up to about 2000 feet, across the interior of western Oregon. That has the stage set for a wintry mix of precipitation later today through Saturday, as moisture feeds northward across western Oregon. Clouds have already spread northward, into southern Oregon, and Doppler radar was showing precipitation as far north as Grants Pass and Medford. Surface reports indicate a wintry mix of precipitation over southwestern Oregon, where temperatures were near 30 degrees. Plain rain was falling in Brookings, on the southern Oregon Coast, where temperatures had warmed into the upper 30s. Computer models show the clouds and precipitation slowly migrating northward later today and tonight. The wintry mix will likely make it into the southern Willamette Valley by late this afternoon and into the extreme north valley by around midnight. Ahead of it, some sunshine should lift northern and central Willamette Valley temperatures into the low 30s. Clouds had already spread over the south valley, where temperatures were in the mid 20s. The precipitation will begin mostly as snow or sleet in the south valley, with a likely transition to sleet and freezing rain, as the air aloft continues to warm. Light northerly surface winds will continue to supply low-level cold air throughout the valley. However, there may be enough surface warming, in the south valley, to change precipitation to just plain rain as early as Saturday morning. Further north, precipitation will be more likely to begin as snow, due to the deeper layer of cold air, especially north of about Salem. A transition to sleet and/or freezing rain is possible in the north valley during the day Saturday, with portions of the central valley possibly changing to plain rain. Forecast precipitation amounts vary from around one-quarter to more than one-half inch, so snow and ice accumulations could be significant, especially in the north valley. However, even small amounts of snow, sleet, and freezing rain can make for very hazardous travel conditions, so be prepared for wintry travel conditions in the Willamette Valley tonight and Saturday. It is possible that the bands of precipitation will stall over the north valley Saturday, where several inches of snow are possible by Sunday morning. Surface Winds: NNE 3-6 this afternoon. Transport Winds: NNE 5 this afternoon. Atmospheric Ventilation Conditions: Maximum mixing height today will be near 1500 feet. Ventilation index 8. High Temperature: Salem\'s high temperature today will be near 34. Humidities: Minimum relative humidity will be near 44%. Sunrise/Sunset: Salem sunset tonight: 4:31pm; sunrise tomorrow: 7:41am. Extended Outlook: Precipitation is expected to taper off Sunday, with the low-level flow turning onshore across most of the valley. That should help most of the Willamette Valley transition to just plain rain. However, there could still be enough cold air coming out of the Columbia Gorge to keep wintry precipitation in the immediate Portland area. Another weather system is forecast to come onshore late Monday. There could still be enough cold air remaining in the Columbia Gorge, and the immediate Portland area, for a wintry mix of precipitation, but the rest of the Willamette Valley should get just rain. Even the Gorge should get scoured out by Tuesday, with warmer Pacific air moving back into the region. Tomorrow (12 Dec): Snow, Sleet, or Freezing Rain...Likely Changing to Rain South. 28/35 Sun (13 Dec): Showers...Possible Snow Near the Gorge. Snow above 1500 feet. 32/42 Mon (14 Dec): Mostly Cloudy. Chance of Rain...Possible Wintry Mix North. 32/40 Tue (15 Dec): Rain. Possibly Starting as Freezing Rain North. 32/47 Wed (16 Dec): Mostly Cloudy and Warmer. Rain Likely Late. 37/49 Thu (17 Dec): Rain Turning to Showers. 42/49 Fri (18 Dec): Mostly Cloudy. Chance of Rain. 38/48 ODA Meteorologist weather at oda.state.or.us From willamette-fcst at listsmart.osl.state.or.us Wed Dec 23 09:48:37 2009 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Wed, 23 Dec 2009 09:48:37 -0800 Subject: [willamette-fcst] Willamette Valley Ag/Burning Forecast Message-ID: Oregon Department of Agriculture Smoke Management Program Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts. Issued: Wednesday, December 23rd, 2009 at 9:00am. Burn Advisory: Agricultural burning is not recommended. Stack burning is not allowed. Weather Discussion: A strong upper-level ridge of high pressure is building over the Pacific Northwest this morning. Clearing skies overnight allowed temperatures to cool below freezing across the Willamette Valley, with dense fog forming by early morning. Visibilities were one-quarter of a mile or less across most of the valley at mid-morning, with temperatures near or slightly below freezing. If you are traveling this morning, be prepared for local icy road surfaces. The ODA surface analysis showed high pressure centered over the northern Willamette Valley and weak offshore pressure gradients across western Oregon. High pressure is forecast to strengthen over eastern Washington and northeastern Oregon later today and Thursday, with increasing offshore flow across western Oregon. Easterly outflow, from the Columbia Gorge, will help to clear the fog from the immediate Portland area later this afternoon, but fog and low clouds should persist across the remainder of the Willamette Valley today, with poor ventilation conditions. Valley highs will struggle to around 40 degrees, before falling back below freezing tonight. Easterly winds will likely keep the extreme north valley clear tonight, but fog should thicken across the central and south valley. Surface Winds: Var 0-4 this morning, NNE 3-8 this afternoon. Transport Winds: ESE 4 this morning, NNE 8 this afternoon. Atmospheric Ventilation Conditions: Maximum mixing height today will be near 1500 feet. Ventilation index 12. High Temperature: Salem's high temperature today will be near 41. Humidities: Minimum relative humidity will be near 70%. Sunrise/Sunset: Salem sunset tonight: 4:35pm; sunrise tomorrow: 7:49am. Extended Outlook: High pressure aloft will build over Oregon Thursday and Christmas Day, with continued dry conditions. At the surface, increasing offshore flow should dry the air mass enough in the north valley for mostly sunny skies. However, the central and south valley will have considerable fog and low clouds. High temperatures will vary from the upper 30s to the mid 40s, depending on the extent of fog. The coolest readings should be in the south valley. The upper-level ridge is forecast to shift east of the region on Saturday, with a weak weather system moving onshore late in the day. A split-flow pattern in the westerly jet stream will take most of the punch out of that system, with only a slight chance of light rain making it into western Oregon Saturday night. However, it should help to break up the fog across the central and southern Willamette Valley. The next weather system is forecast to move mainly south of the region, into California, Sunday and Monday. Some clouds and light precipitation could extend northward into western Oregon. Another weak system is forecast to come onshore about next Tuesday. Thu (24 Dec): Mostly Sunny North. Fog Central and South with Partial PM Clearing. 27/42 Fri (25 Dec): Sunny North. Fog Central and South with PM Clearing. 27/43 Sat (26 Dec): Increasing Clouds. Slight Chance of Very Light Rain Late. 29/44 Sun (27 Dec): Mostly Cloudy. Chance of Light Rain. Snow Level 3000 Feet. 34/44 Mon (28 Dec): Mostly Cloudy. Slight Chance of Light Rain. Snow Level 3000 Feet. 34/44 Tue (29 Dec): Mostly Cloudy. Chance of Light Rain. Snow Level 3000 Feet. 35/44 Wed (30 Dec): Partly Cloudy. 33/46 ODA Meteorologist weather at oda.state.or.us From willamette-fcst at listsmart.osl.state.or.us Thu Dec 24 10:04:01 2009 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Thu, 24 Dec 2009 10:04:01 -0800 Subject: [willamette-fcst] Willamette Valley Ag/Burning Forecast Message-ID: Oregon Department of Agriculture Smoke Management Program Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts. Issued: Thursday, December 24th, 2009 at 9:00am. Burn Advisory: Agricultural burning is not recommended. Stack burning is not allowed. Weather Discussion: A strong upper-level ridge of high pressure is continuing the dry northwesterly flow aloft over the Pacific Northwest. The freezing level over western Oregon is around 9000 feet, with the warm air aloft trapping cold air near the interior valley surfaces. Fog is widespread again this morning across the Willamette Valley. Visibilities are around one-quarter of a mile, or less, in most areas. The moist low-level air held valley temperatures near the freezing mark overnight, with some spots dropping into the upper 20s. The mid-morning ODA surface analysis showed increasing offshore flow, with high pressure strengthening over eastern Washington and a thermal trough building northward along the southern Oregon coast. Easterly winds were keeping the coastline clear this morning, where sushine had already warmed temperatures into the mid to upper 30s. Meanwhile, only a light northerly drift was being felt in the foggy Willamette Valley, at mid-morning, with temperatures ranging from the upper 20s to just above freezing. Easterly outflow was beginning to increase at the western end of the Columbia Gorge but had not penetrated as far west as Troutdale, where it was still foggy. Very still air overnight allowed temperatures to drop into the single digits across sections of central and eastern Oregon by early this morning. Meacham, in northeastern Oregon, was just 1 degree above zero at mid-morning. Burns recorded a minimum of 4 degrees and Lakeview dipped down to 7 degrees. Redmond, in north-central Oregon, had a minimum of 11. Easterly outflow is forecast to increase, from the Columbia Gorge, and will help to clear fog from the extreme north valley later today. However, fog and low clouds should be more persistent from about Salem southward to Eugene. Valley highs will struggle into the mid to upper 30s in the foggy south valley but should climb into the low 40s, where the sun is able to pierce the fog, in the north valley. Low level temperatures inversions will continue to make for poor ventilation conditions. It will be a foggy Chistmas Eve for most of the central and southern Willamette Valley, where Santa will need Rudolph to deliver his toys. It will also be chilly, again, with temperatures near the freezing mark. Increasing easterly winds will likely keep fog from forming in the western Columbia Gorge and much of the immediate Portland area. Surface Winds: NNE 3-8 this morning, NNE 5-10 this afternoon. Transport Winds: NNE 8 this morning, NNE 10 this afternoon. Atmospheric Ventilation Conditions: Maximum mixing height today will be near 1500 feet. Ventilation index 15. High Temperature: Salem's high temperature today will be near 42. Humidities: Minimum relative humidity will be near 59%. Sunrise/Sunset: Salem sunset tonight: 4:35pm; sunrise tomorrow: 7:49am. Extended Outlook: The upper-level ridge of high pressure will move directoy over Oregon Christmas Day, with continued dry conditions. At the surface, increasing offshore flow should dry the air mass enough in the north valley for mostly sunny skies. However, the central and south valley will have considerable fog and low clouds. High temperatures will vary from the upper 30s to the mid 40s, depending on the extent of fog. The coolest readings should be in the south valley. The upper-level ridge is forecast to shift east of the region on Saturday, with a weak weather system moving onshore late in the day. A split-flow pattern in the westerly jet stream will take most of the punch out of that system, with only a slight chance of sprinkles making it onshore Saturday night...mainly near the California border. However, increasing offshore winds may break up the fog across more of the Willamette Valley. The next weather system is forecast to move mainly south of the region, into California, Sunday and Monday. Some middle and high clouds could spread across western Oregon, but it is unlikely that this system will be strong enough to lift the fog from the Willamette Valley. The next system is forecast to come onshore late Tuesday or Wednesday of next week, but it may not be strong enough to produce much in the way of rain. A stronger system is forecast to finally break through the ridge and bring some rain, to close out the year, on Thursday. Tomorrow (25 Dec): Sunny North. Fog Central and South with PM Clearing. 27/43 Sat (26 Dec): Foggy Morning Central and South...Increasing Clouds PM. 27/43 Sun (27 Dec): Mostly Cloudy/Foggy. 30/44 Mon (28 Dec): Mostly Cloudy/Foggy. 32/45 Tue (29 Dec): Mostly Cloudy. Slight Chance of Rain Late. Snow Level 4000 Feet. 33/45 Wed (30 Dec): Mostly Cloudy. Slight Chance of Rain. Snow Level 4-5000 Feet. 34/45 Thu (31 Dec): Rain Likely and Warmer. Snow Level Rising to 6000 Feet. 35/50 ODA Meteorologist weather at oda.state.or.us From willamette-fcst at listsmart.osl.state.or.us Thu Dec 24 12:17:07 2009 From: willamette-fcst at listsmart.osl.state.or.us (Willamette Valley Ag/Burning Forecast) Date: Thu, 24 Dec 2009 12:17:07 -0800 Subject: [willamette-fcst] Willamette Valley Ag/Burning Forecast Message-ID: Oregon Department of Agriculture Smoke Management Program Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts. ...No Updates Before Tuesday, January 5th, 2010... Issued: Thursday, December 24th, 2009 at 12:00pm. Burn Advisory: Agricultural burning is not recommended. Stack burning is not allowed. Weather Discussion: A strong upper-level ridge of high pressure is continuing the dry northwesterly flow aloft over the Pacific Northwest. Warming aloft has lifted the freezing level over western Oregon to around 9000 feet, with cold air trapped near the interior valley surfaces. Visible satellite imagery showed widespread fog across most of the Willamette Valley late this morning, with visibilities locally less than one-quarter of a mile. Temperatures had only warmed to near the freezing mark, after morning minimums around 30 degrees. Some extreme north-valley areas, like Troutdale, were picking up just enough dry easterly outflow, from the Columbia Gorge, to clear the fog. The Troutdale Airport was reporting sunny skies with the temperature in the mid 30s. That may sound pleasant, but easterly winds, gusting to over 20 mph, were dropping the windchill temperature into the mid 20s. The late-morning ODA surface analysis showed a continuing increase in the offshore flow. Easterly winds were keeping the coastline clear, where sushine had already warmed temperatures well into the 40s. Brookings, on the south coast, was in the mid 50s. Skies were generally sunny from the Cascades eastward across the state. Midday temperatures were mostly in the upper 20s to mid 30s...including over the passes. Offshore flow is forecast to increase, with drying Gorge east winds helping to clear fog from the extreme north valley later today. However, fog and low clouds should persist south of about Salem. Valley highs will struggle into the mid to upper 30s in the foggy south valley but should climb into the low 40s, where the sun is able to make an appearance, in the north valley. Low level temperatures inversions will continue to make for poor ventilation conditions. It will be a foggy Chistmas Eve for most of the central and southern Willamette Valley, where Santa will need Rudolph to deliver his toys. It will also be chilly, again, with temperatures near the freezing mark. Increasing easterly winds will likely keep fog from forming in the western Columbia Gorge and much of the immediate Portland area. Surface Winds: NNE 5-10 this afternoon. Transport Winds: NNE 10 this afternoon. Atmospheric Ventilation Conditions: Maximum mixing height today will be near 1500 feet. Ventilation index 15. High Temperature: Salem's high temperature today will be 36-42. Humidities: Minimum relative humidity will be near 68-85%. Sunrise/Sunset: Salem sunset tonight: 4:35pm; sunrise tomorrow: 7:49am. Extended Outlook: The upper-level ridge of high pressure will move directly over Oregon Christmas Day, with continued dry conditions. At the surface, increasing offshore flow should dry the air mass enough in the north valley for mostly sunny skies. However, the central and south valley will have considerable fog and low clouds. High temperatures will vary from the mid 30s to the mid 40s, depending on the extent of fog. The coolest readings should be in the south valley. The upper-level ridge is forecast to shift east of the region on Saturday, with a weak weather system moving onshore late in the day. A split-flow pattern in the westerly jet stream will take most of the punch out of that system, with only a slight chance of sprinkles making it onshore Saturday night and possibly into the western sections of the Willamette Valley and into the southwestern valleys. This system may help to lift the fog a bit, but substantial clearing is unlikely. The next weather system is forecast to move mainly south of the region, into California, Sunday and Monday. Some middle and high clouds could spread across western Oregon, with little to no improvement in ventilation conditions. The next system is forecast to come onshore late Tuesday or Wednesday of next week and may bring some sprinkles to the region. A stronger system is forecast to finally break through the ridge and bring some rain, to close out the year, on or about next Thursday. Tomorrow (25 Dec): Sunny North. Fog Central and South with PM Clearing. 27/43 Sat (26 Dec): Foggy Morning Central and South...Increasing Clouds PM. 27/43 Sun (27 Dec): Mostly Cloudy/Foggy. 30/44 Mon (28 Dec): Mostly Cloudy/Foggy. 32/45 Tue (29 Dec): Mostly Cloudy. Slight Chance of Rain Late. Snow Level 4000 Feet. 33/45 Wed (30 Dec): Mostly Cloudy. Slight Chance of Rain. Snow Level 4-5000 Feet. 34/45 Thu (31 Dec): Rain Likely and Warmer. Snow Level Rising to 6000 Feet. 35/50 ODA Meteorologist weather at oda.state.or.us