[willamette-fcst] Forecast - Thursday, February 19th, 2009
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Thu Feb 19 09:01:43 PST 2009
Daily Smoke Management Forecast
Oregon Department of Agriculture
Smoke Management Program
Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts.
Thursday, February 19th, 2009 at 9:00am.
Agricultural burning is allowed. Suggested burn times are from 11:00am until 4:00pm.
Stack burning is not allowed.
Fair skies and light winds overnight allowed temperatures,
once again, to drop near or below freezing across the
Willamette Valley. Hillsboro dipped to 28 degrees, Salem
dropped to 30 and Portland 31. An upper-level low pressure
center continues to be anchored several hundred miles off
the northern California coastline this morning. Satellite
imagery showed an impressive cloud-shield circulating around
it, with all of the precipitation staying well offshore.
Middle and high clouds were spreading northward across
Oregon and Washington. There were also areas of fog and low
clouds this morning in the southern Willamette Valley and
east of the Cascades.
Counter-clockwise circulation around the offshore weather
system is producing southwesterly flow aloft over Oregon and
warming the air mass. The freezing level over Salem had
climbed from 5200 feet yesterday morning to 7500 feet this
morning. Warm air aloft will keep mixing heights below
about 1500 feet today. Transport winds are expected to
remain fairly light and mostly from the northeast, so stack
burning is not allowed.
The ODA surface analysis showed a little stronger offshore
pressure gradients across western Oregon, compared with
yesterday morning. Easterly winds were were blowing around
5-15 mph along the coast at mid-morning with generally calm
winds in the Willamette Valley. Mid-mornig temperatures
were in the low to mid 30s in the Willamette Valley but had
already warmed into the mid 40s along the coast at Newport
and North Bend. Skies were mostly cloudy with some fog in
the Eugene area.
Like yesterday, the fog should clear later this morning, but
there will still be considerable middle and high clouds
filtering the late-winter sunshine. Willamette Valley
temperatures should climb mostly into the mid and upper 50s
this afternoon (most areas will be a degree or two warmer
than yesterday). Surface winds will remain lightly offshore.
NNE 3-6 this morning, NE 3-7 this afternoon.
NNE 6 this morning, NE 7 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 1500 feet. Ventilation index 11.
Salem\'s high temperature today will be near 58.
Minimum relative humidity will be near 36%.
Salem sunset tonight: 5:46pm; sunrise tomorrow: 7:04am.
There will continue to be considerable middle and high
cloudiness filtering the sunshine across Oregon Friday and
Saturday. The air mass will continue to be mild with
temperatures running a couple of degrees above normal in
most areas. As the storm off the California coastline
slowly moves eastward, the chance of rain will increase
significantly by Saturday night.
An upper-level low pressure system will finally move close
enough to the coastline by Sunday for a good chance of light
rain across western Oregon. Temperatures will remain mild
with increasing southwesterly flow aloft. A cold front is
forecast to finally move across western Oregon Sunday night
or Monday with a showery and cooler weather pattern setting
up for much of next week. Snow levels will drop
dramatically by the middle of next week, with considerable
new snow possible over the Cascade passes. Colder air aloft
should improve ventilation conditions across western Oregon.
Tomorrow (20 Feb): Areas of AM Fog. Mostly Cloudy and Mild in the Afternoon. 32/57
Sat (21 Feb): Areas of AM Fog. Mostly Cloudy and Mild in the Afternoon. 34/57
Sun (22 Feb): Rain Likely. Snow Level 5-6000 Feet. 38/53
Mon (23 Feb): Rain Likely at Times. Snow Level 5000 Feet...Dropping late. 40/50
Tue (24 Feb): Showers. Mountain Snow. Snow Level 3000 Feet. 38/50
Wed (25 Feb): Showers. Mountain Snow. Snow Level 3000 Feet. 37/49
Thu (26 Feb): Showers. Mountain Snow. Snow Level 2000 Feet. 36/48
weather at oda.state.or.us
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