[willamette-fcst] Forecast - Tuesday, May 20th, 2008
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Tue May 20 08:13:28 PDT 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.
Tuesday, May 20th, 2008 at 9:00am.
Agricultural burning is allowed. Suggested burn times are from now until 6:30pm.
Straw stack burning is allowed from now until 6:30pm.
A cooling trend began Sunday across Oregon and will really
kick in today with a fairly strong cold front sweeping
across the state. Infrared satellite imagery showed cloudy
skies covering Washington and Oregon at mid-morning. A
well-defined solid cloud-band stretched from NW Washington
through Western Oregon with the back edge just moving
onshore. Doppler radar showed rain across much of Eastern
Washington extending southward into NE Oregon with an
enhanced zone of rain across Western Washington and Western
Oregon, in assoication with the cold front.
Cloudy skies helped to hold Westner Oregon temperatures in
the low to mid 50s overnight, but they were still dropping
at mid-morning. Over one-quarter of an inch of rain fell
along the northern coastal strip this morning with one-tenth
to one-quarter of an inch falling so far across the
Willamette Valley. The fairly strong cold front is forecast
to move through the Willamette Valley in the next couple of
hours with the steady rain tapering off. Strong onshore
flow will keep skies generally cloudy with an upper-level
trough helping to maiintain scattered showers through
Wednesday and perhaps into Thursday. Temperatures will
struggle to reach the low 60s this afternoon...20-25 degrees
cooler than on Monday.
The freezing level over Western Oregon, which was above
15,000 feet Saturday, dropped to between 12,000 and 14,000
feet Monday to between 9000 and 12,000 feet this morning.
It will fall rapidly today, in the wake of the cold front,
to near 6000 feet this afternoon. Rain was falling over the
Cascade passes at mid-morning with pass temperatures in the
low 40s. The snow level will likely drop to near 4500 feet
later today with a couple of inches of wet snow possible
over the Cascade Passes by tonight.
The ODA surface analysis showed high pressure building into
the Southern Oregon Coast, in the wake of a cold front
moving across the western half of Washington and Oregon.
Onshore flow at the surface and colder air aloft will
combine to create good ventilation condions across Western
Oregon today, so stack burning is allow.
Cloudy skies extend well out ahead of the surface cold front
this morning and cover almost the entire Pacific Northwest.
Light rain was falling as far east as Ontario, near the
Idaho border. The air mass is still quite warm and somewhat
unstable over Eastern Oregon with many areas still in the
60s this morning. Baker City even reported a thunderstorm
Rain will increase east of the Cascades this afternoon, as
the cold front, currently over Western Oregon, pushes east
of the Cascades. There will continue to be a threat of
thunderstorms, ahead of the cold front, over much of Eastern
Oregon this morning. In the wake of the cold front, steady
rain this afternoon will turn showery as brisk and cooler west
winds, gusting as high as 35 mph, stabilize the air mass east
of the Cascades enough to prohibit thundershower development.
SW 10-15 this morning, W 10-15 this afternoon.
W 12 this morning, W 18 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 5000 feet. Ventilation index 90.
Salem\'s high temperature today will be near 62.
Minimum relative humidity will be near 58%.
Salem sunset tonight: 8:40pm; sunrise tomorrow: 5:37am.
A cold upper-level trough will move over the Pacific
Northwest Tonight and Wednesday for continued cool
temperatures and the threat of showers. High pressure will
slowly push closer to the coastline Thursday with the flow
aloft turning more northerly and drying out some.
A cool upper-level trough is forecast to set up camp over the
Western United States through the holiday weekend with a continued
chance of showers for Oregon...mainly over the mountains.
Temperatures should be near to slightly below normal.
Tomorrow (21 May): Mostly Cloudy and Cool. Chance of Showers. Snow Level 5000 Feet. 46/60
Thu (22 May): Partly Sunny. A Little Warmer. 43/62
Fri (23 May): Partly Cloudy. Slight Chance of Showers. 43/65
Sat (24 May): Partly Cloudy. Slight Chance of Showers. A Little Warmer. 43/69
Sun (25 May): Partly Cloudy. Slight Chance of Showers. 44/70
Mon (26 May): Partly Cloudy. 44/72
Tue (27 May): Chance of Showers. 46/71
weather at oda.state.or.us
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