[willamette-fcst] Forecast - Wednesday, February 25th, 2009
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Wed Feb 25 08:55:00 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.
Wednesday, February 25th, 2009 at 9:00am.
Agricultural burning is allowed. Suggested burn times are from 9:00am until 4:00pm.
Straw stack burning is allowed, for dry stacks, from 9:00am until 4:00pm.
A strong and moist west-southwesterly flow aloft continued
the shower activity across Washington and Oregon overnight.
With the showery nature of the precipitation, there was a
wide variety of rainfall amounts over the past 24 hours.
Some coastal and inland valley locations, such as Newport
and McMinnville, received only around one-tenth of an inch,
while other areas, like North Bend and Eugene, picked over
over one inch of rain. Cloudy and rainy conditions kept
overnight temperatures in the 40s across the lower
elevations of western Oregon.
Snow levels remained around 4000 feet, in the Cascades
overnight, with about an inch of new snow on the passes this
morning. Significant amounts of snow have fallen in the
higher elevations on Mt. Hood. Timberline lodge reported 12
inches of new snow in the past 24 hours and 52 inches of new
snow in the past 72 hours. That is a welcome site, for the high
country, after drier than normal conditions since early January.
The moist west-southwesterly flow off the Pacific Ocean will
strengthen today, as a cold upper-level low pressure area
drops southward, from southern British Columbia, to off the
northern Washington Coast. Satellite imagery showed cloudy
skies across virtually all of Washington and Oregon at
mid-morning. Doppler radar showed bands of showers rotating
inland and across the entire region. Showers were even
making it east of the Cascades, especially over higher terrain.
With little or no sunbreaks today, and progressively cooler
air aloft moving over the region, temperatures will only
warm a couple of degrees from their current levels. Valley
highs should top out near 50 degrees, down a few degrees
from yesterday, with frequent showers. Ventilation
conditions will be good today, but straw stacks may loaclly
be too wet for burning. The Cascades will see around 5-10
inches of new snow, above 3500 feet, where Winter Weather
Advisories are in effect.
SW 5-15 this morning, SW 10-15 G25 this afternoon.
SW 20 this morning, SW 30 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 3900 feet. Ventilation index 117.
Salem\'s high temperature today will be near 50.
Minimum relative humidity will be near 66%.
Salem sunset tonight: 5:55pm; sunrise tomorrow: 6:55am.
A cold upper-level low-pressure system is forecast to
continue to slowly sag southward, along the Washington
Coast, tonight. That will increase the showers and
southwesterly winds across western Oregon with snow levels
lowering to at or below 1000 feet by Thursday morning.
Another 5-10 inches of snow could fall in the Cascades
overnight with 2-4 inches of snow possible over the coastal
As the very cold upper-level low-pressure system swings
onshore Thursday, wet snow accumulations are also possible
in the higher hills around the Willamette Valley. Showers
could mix with or turn to snow even down to the Willamette
Valley Floors. The best chance for sticking snow on the
valley floors appears to be early Thursday. Significant
accumulations are not expected below 500 feet, but wet snow
could locally cover the ground under heavier showers. High
temperatures should still climb into the mid 40s Thursday
afternoon, with brisk southwesterly winds. The mountains
will likely see an additional 2-7 inches of snow.
The upper-level low-pressure system is forecast to move east
of the Cascades Thursday night with showers tapering off and
skies clearing. That will allow for much colder overnight
temperatures. Valley minimums will likely drop to near or
below freezing. A transitory ridge of high pressure may
bring a mostly dry, but quite cool, day Friday, with a touch
The next weather system is forecast to develop further
offshore, with increasing southwesterly flow aloft briefly
lifting snow levels to near the Cascade passes Saturday
afternoon. That system is forecast to move onshore with
rain and blustery winds Saturday night and Sunday. Snow
levels should drop back below the Cascade passes Sunday.
Showers will continue Monday and Tuesday with snow in the
mountains. Another cool weather system is forecast to drop
into the region, from the Gulf of Alaska, on Wednesday.
Tomorrow (26 Feb): Showers. Snow Level near 500 Feet. 37/44
Fri (27 Feb): Partly Sunny and Cool. Slight Chance of a Shower. 30/50
Sat (28 Feb): Increasing Clouds. Chance of PM Rain. Snow Level Rising to 4000 Feet. 31/49
Sun (01 Mar): Rain. Snow Level Dropping to 3000 Feet. 39/52
Mon (02 Mar): Showers. Snow Level Near 3000 Feet. 37/50
Tue (03 Mar): Mostly Cloudy. Chance of Showers. Snow Level near 4000 Feet. 36/52
Wed (04 Mar): Rain Increasing. Snow Level 4000 Feet. 36/52
weather at oda.state.or.us
More information about the willamette-fcst