[willamette-fcst] Forecast - Tuesday, December 8th, 2009
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Tue Dec 8 09:11:38 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.
Issued:
Tuesday, December 8th, 2009 at 9:00am.
Burn Advisory:
Agricultural burning is allowed. Suggested burn times are from 12:00pm until 2:30pm.
Stack burning is not allowed.
Weather Discussion:
A weak upper-level disturbance, in the cold northerly flow
aloft, will drop southward, from British Columbia to just
off the Oregon Coast this afternoon. It does not appear as
if it will have enough moisture to bring any precipitation
to the region, so skies should stay mostly sunny over western
Oregon. There will be some middle and high clouds, mainly near
the coast. Offshore pressure gradients should relax slightly
today, with some decrease in the north-northeasterly winds
across western Oregon.
After a very cold start, with western Oregon temperatures
mostly in the teens, afternoon highs will struggle to around
the freezing mark in the Willamette Valley. I\'ll have a rundown
of the cold morning minimums on the noon update.
Surface Winds:
NNE 5-15 this morning, NNE 5-15 this afternoon.
Transport Winds:
NNE 10 this morning, NNE 10 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 2700 feet. Ventilation index 27.
High Temperature:
Salem\'s high temperature today will be near 29.
Humidities:
Minimum relative humidity will be near 30%.
Sunrise/Sunset:
Salem sunset tonight: 4:31pm; sunrise tomorrow: 7:39am.
Extended Outlook:
Cold and dry northerly flow aloft will continue Wednesday
and Thursday. Decreasing surface winds will allow for even
colder overnight temperatures across western Oregon. Mostly
sunny skies will help afternoon highs recover to around freezing.
By Friday, a westerly flow aloft will begin to undercut the
offshore ridge...taking Pacific storm systems into
California. The flow aloft over Oregon will back from
northerly to northwesterly. Clouds will be on the increase
across extreme southern Oregon, but skies should remain
mostly sunny over the Willamette Valley with moderating temperatures.
By Saturday morning, moisture is forecast to spread
northward into the Willamette Valley. The air mass aloft
will be warming, but continued offshore flow at the surface
should allow enough low-level cold air to remain in place
for precipitation to fall mainly as snow, sleet, or freezing
rain. there may be enough warming for areas of the central
and southern valley to changeover to plain old rain, but
expect conditions to remain icy in the Portland area and in
the Columbia Gorge.
By Sunday, most of the Willamette Valley should see
temperatures moderate to above freezing, with precipitation
falling as rain. However, there may still be areas of
wintry precipitation in and near the Columbia Gorge. A much
warmer weather system is forecast to come onshore late
Monday, which should scour out any remaining low-level cold
air trapped in the Gorge.
Tomorrow (09 Dec): Mostly Sunny and Cold. 11/30
Thu (10 Dec): Mostly Sunny and Cold. 15/34
Fri (11 Dec): Mostly Sunny and Cold. 19/38
Sat (12 Dec): Snow, Sleet, or Freezing Rain Likely. Likley Changing to Rain South. 28/35
Sun (13 Dec): Chance of Rain...Possible Wintry Mix Near the Gorge. 32/42
Mon (14 Dec): Rain Increasing Late. Turning Warmer. 36/50
Tue (15 Dec): Rain Likely. Mild. 42/52
ODA Meteorologist
weather at oda.state.or.us
More information about the willamette-fcst
mailing list