[willamette-fcst] Forecast - Thursday, February 14th, 2008
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Thu Feb 14 10:02:07 PST 2008
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 9 am Tuesday, February 18th...
Thursday, February 14th, 2008 at 9:00am.
Agricultural burning is not recommended.
Stack burning is not allowed.
A cool upper-level trough brought scattered light showers
and low snow levels to Washington and Oregon Wednesday. The
air mass slowly stabilized overnight, as the trough moved
southeastward into Nevada and Utah. The Pacific Northwest
is under the influence of north-northeasterly flow aloft
this morning, with a ridge of high pressure building into
Temperatures dropped into the 30s overnight across Western Oregon
with some locations falling below the freezing mark. Astoria, Newport,
and Corvallis all dropped to 30 degrees early this morning, while
McMinnville dipped to 29. Hillsboro dropped to a low of 28 degrees.
Low clouds and patchy fog helped to keep temperatures just above freezing
in Salem and Eugene, with a lows of 35 and 33 respectively.
The air mass aloft was still very cold early this morning. The freezing
level over Salem was measured at just 2400 feet at 4 am. Satellite
imagery showed areas of low clouds in the Willamette Valley this morning,
as a result of the continued weak onshore flow across Western Oregon. An
upper-level ridge will quickly build over the region today with rapid warming
aloft and surface pressure gradients becoming northerly. That will dry the
air mass and help to clear the low clouds from the western valleys for mostly
sunny skies this afternoon. Temperatures will climb to near normal and
freezing levels will quickly rebound to above 6000 feet by late this afternoon.
Rapid warming aloft will reduce mixing heights this afternoon. Combined with
northerly winds, that will make for poor ventilation conditions over the
Willamette Valley, so stack burning is not allowed and agricultural burning is
not recommended. With the air mass drying out, clear skies and light winds
tonight will allow temperatures to drop to near or below freezing across much
of Western Oregon with strong low-level temperature inversions developing.
NW 5 this morning, N 5-10 this afternoon.
NE 10 this morning, NE 10 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 2000 feet. Ventilation index 20.
Salem\'s high temperature today will be near 50.
Minimum relative humidity will be near 58%.
Salem sunset tonight: 5:38pm; sunrise tomorrow: 7:13am.
A very weak front will ride over the top of the ridge of
high pressure and across across Southern British Columbia
and Washington Friday. Some clouds will likely make it
southward into Oregon, with the surface flow becoming
onshore, but it is unlikey that rain will make it this far
south, except for a chance of drizzle or very light rain
along the north coastal region. Freezing levels will rise
to near 8000 feet by Friday afternoon, and valley
temperatures will climb into the low to mid 50s.
Low clouds and weak onshore flow will keep temperatures from
falling as rapidly Friday night across Western Oregon, with
most areas staying above freezing. A massive ridge of high
pressure is still forecast to build over the region this
weekend, which will direct storm activity northward into
Central British Columbia and bring spring-like weather to
Oregon and Washington. Surface gradients will turn offshore
Saturday afternoon through Sunday and freezing levels will
be near 9000 feet. That should help afternoon temperatures
climb to well above normal Saturday and possibly approach
records by Sunday with valley highs in the low 60s.
The strong upper-level ridge will shift eastward, over the
Rockies, early next week. That will allow a series of
progressively stronger Pacific storms to move into the
region. There is a slight chance of rain with the first
system Monday night. Rain is likely by Tuesday night with a
more seasonal stormy weather pattern forecast by the middle
of next week.
The February update to the Seasonal Climate Forecast is
available on the ODA website. You can view it by going to
and clicking on: ODA\'s Seasonal Climate Forecast in either
PowerPoint or Adobe PDF format. The current outlook goes
through May, 2008.
Tomorrow (15 Feb): Partly Cloudy. 30/54
Sat (16 Feb): Sunny and Mild. 35/55
Sun (17 Feb): Sunny with Near-Record Warmth. 35/60
Mon (18 Feb): Mostly Sunny & Continued Mild. Chance of Light Rain Late. 36/57
Tue (19 Feb): Chance of Rain Early...Rain Likely Late. Snow Level Near 6000 Feet. 38/54
Wed (20 Feb): Rain and Blustery. Snow Level 5000 Feet. 40/50
Thu (21 Feb): Showers and Blustery. Mountain Snow. Snow Level 2500 Feet. 38/48
weather at oda.state.or.us
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