[willamette-fcst] Forecast - Wednesday, February 11th, 2009
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Wed Feb 11 09:00:59 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 11th, 2009 at 9:00am.
Agricultural burning is allowed. Suggested burn times are from now until 3:30pm.
Stack burning is not allowed.
A cool weather system, from the Gulf of Alaska, brought rain
and snow to the region Tuesday, with the snow level
initially near the valley floors. The snow level lifted to
about 1500 feet overnight, and the precipitation tapered
off. Skies were mostly cloudy overnight with occasional
showers across western Oregon. Temperatures stayed above
freezing with valley minimums in the mid to upper 30s.
Satellite imagery and surface reports showed the
low-pressure center, off the southern Oregon coast,
continuing to slowly drift southeastward. A fairly
impressive cloud-shield, wrapping around it, spread across
most of Oregon. Doppler radar showed numerous showers,
rotating northward, from northern California to Portland,
Oregon. As the low-pressure center slowly weakens and comes
onshore, near the Oregon/California border this afternoon,
shower activity should taper off, from north to south,
across Oregon. Temperatures will stay below normal, with
valley highs only near 45 degrees (normal would be in the
The air mass is slowly warming over the region. The morning
soundings measured the freezing levels over Salem and
Medford at 2900 and 3500 feet respectively. Another few
inches of snow are possible today, above about 2000 feet,
before the showers taper off tonight. Showers will be most
numerous across sotuhwestern Oregon. Transport winds this
morning were southeasterly and should back to northeasterly,
as the low-pressure system continues to move south and east.
Northeasterly transport winds are not favorable for stack
burning, so it is not allowed today.
Plan on continued winter driving conditions over mountain
passes above 1500 feet today and tonight. ODOT road cameras
showed wet pavement with areas of slush over the coastal
passes and packed snow over the Cascade passes.
Temperatures have remained just warm enough in the Columbia
Gorge to avoid significant snow accumulation at river-level,
where travel conditions appeared okay this morning. Skies
should begin to clear tonight, which will allow many areas
in the valley and in the Gorge to fall below freezing by
Thursday morning. Some road surfaces could become slick, so
travel with caution overnight and early Thursday. There may
also be areas of fog formation overnight in the Willamette Valley.
NE 5-15 this morning, N 5-15 this afternoon.
E 12 this morning, NE 12 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 2000 feet. Ventilation index 24.
Salem\'s high temperature today will be near 46.
Minimum relative humidity will be near 60%.
Salem sunset tonight: 5:35pm; sunrise tomorrow: 7:17am.
The next weather system, in this latest series of cool
storms from the Gulf of Alaska, is forecast to take a
slightly more of a southerly track, but it should bring more
rain and snow to western Oregon late Thursday and Friday.
With increasing offshore flow, the snow level may drop to
around 500-1000 feet early Friday, with accumulation snow
likely again over the coastal and Cascade passes. Some wet
snow may locally mix to the valley floors, but significant
accumulations below 1000 feet are not expected. The bulk of
the moisture from this system will move into southwestern
Oregon and northern California.
The next weather system is forecast to take an even more
southerly track, Sunday and Monday, with the bulk of the
moisture staying south of Oregon. That will maintain a cool
offshore low-level flow across western Oregon, so
temperatures will stay well below normal with low snow
levels. the next system is forecat to come onshore Tuesday,
and that one may also be directed mainly into California.
Thu (12 Feb): Increasing Clouds. Chance of PM Rain. Snow Level Dropping to 1000 Feet. 28/45
Fri (13 Feb): Decreasing Rain and Snow. Snow Level Near 1000 Feet. 33/44
Sat (14 Feb): Partial Clearing and Cool. Slight Chance of a Shower. 30/47
Sun (15 Feb): Chance of Showers and Cool. Snow Level Near 2000 Feet. 30/47
Mon (16 Feb): Mostly Cloudy. Slight Chance of Showers. Snow Level 2500 feet. 32/48
Tue (17 Feb): Increasing Chance of Rain. Snow Level 2-3000 Feet. 33/48
Wed (18 Feb): Chance of Showers. Snow Level 3000 Feet. 36/50
weather at oda.state.or.us
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