[willamette-fcst] Forecast - Tuesday, January 22nd, 2008
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Tue Jan 22 16:44:51 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.
Tuesday, January 22, 2008 at 4:45 pm.
Burn Advisory For Wednesday, January 23, 2008:
Agricultural burning is not recommended.
Stack burning is not allowed.
This morning was the coldest so far this winter for much of
Oregon. Meacham, in Northeast Oregon, dropped to 23 degrees
below zero for the cold spot in the state. Burns dipped to
14 below zero, Redmond bottomed out at 8 below and Pendleton
dropped to 3 above zero. The Dalles, at the east end of the
gorge, was just 11 degrees this morning. West of the
Cascades, Portland dropped to 23 this morning and Hillsboro
was 19 degrees. Salem dipped to 23, while Corvallis and
Eugene fell to 21. Even the coastline was cold with Astoria
starting out at 26 degrees and Newport 30 with east winds
gusting to near 30 mph.
Today was a repeat of Monday with sunny skies, cool
temperatures, and strong offshore flow across the state.
Highs generally climbed into the low 40s across the
Willamette Valley. The coast was warmer with easterly winds
yielding another bright and sunny day. Afternoon
temperatures ranged from the low 40s along the north coast
to the 50s south of about Coos Bay. It remained well below
freezing east of the Cascades this afternoon, with 28
degrees at Redmond being one of the warmer spots. Pendleton
managed to creep into the low 20s, while Baker City strugled
to reach 11 degrees. La Grande topped out at 14. The
Dalles crept up to 33 degrees.
The late-afternoon ODA surface analysis showed strong high
pressure centered over NE Oregon and a low perssure trough
along the Oregon Coast. That combination of pressure
systems was responsible for the offshore flow across the
state again today...although it was a bit weaker for maost
areas than on Monday. The exception to that was in the
Columbia Gorge, where east winds increased in strength
today...continuing to push cold air from the Columbia Basin
into Western Oregon. Troutdale, near the western end of the
gorge, only managed to reach 35 degrees this afternoon with
east winds gusting over 35 mph at times and windchill values
near 20 degrees.
The freezing level over salem rose from the surface this
morning to 4300 feet this afternoon. Mixing heights rose to
about 2000 feet this afternoon but ventilation conditions
will deteriorate tomorrow as continued warming aloft
strengthens a low-level temperature inversion over Western
Oregon. That is why stack burning is not allowed
Temperatures will rapidly fall this evening under clear
skies and continued dry offshore flow. Wind-sheltered areas
of the Willamette Valley will see overnight lows drop into
the upper teens. The air mass over Oregon is extremely dry
with dew-point temperatures in the teens or single digits
west of the Cascades and single digits to below zero across
Central and Eastern Oregon. With the lack of an insulating
blanket of snow, frost sensitive crops will continue to be
in danger, from the cold temperatures, for at least the next
couple of mornings.
A decrease in the offshore flow, slighly warmer air aloft,
and a full day of sunshine should help temperatures climb
into the low 40s Wednesday afternoon. Under clear skies,
temperatures will rapidly fall back into the 20s Wednesday night.
N-NE 5-10 Wednesday morning, N-NE 5-15 Wednesday afternoon.
NE 5-10 Wednesday morning, NE 10-15 Wednesday afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height Wednesday will be near 1500 feet. Ventilation index 8.
Salem\'s high temperature Wednesday will be near 42.
Minimum relative humidity will be near 40%.
Salem sunrise Wednesday: 7:41 am; sunset Wednesday: 5:07 pm.
A weather system is forecast to drop southeastward from the
Gulf of Alaska to just off the Oregon Coast by Thursday
afternoon. That will maintain the surface offshore flow and
keep low-level cold air in place across Western Oregon,
while increasing southwesterly flow aloft feeds Pacific
moisture over the cold dome.
This is a classic set-up for snow across Western Oregon for
Thursday afternoon. The limiting factor will be the amount
of moisture forecast to spread inland. At this time, it
appear that snowfall will be light with the greatest chance
for accumulating snow in the central and southern sections
of Western Oregon...especially in the coastal range. It is
possible that the Willamette Valley could pick up an inch or
two of snow, if enough moisture circulates that far inland.
The bulk of the moisture is expected to stay offshore, as
the system moves southward along the Oregon Coast, then
dives southeastward into Northern California.
Skies should begin to clear over the Willamette Valley
Thursday night with low-level cold air still in place across
all of Oregon. Friday appears to be a break-day from any
storm activity with mostly sunny skies and cool temperature
The forecast gets very tricky after Friday with a stronger
system forecast by all the computer models to drop
southeastward from the Gulf of Alaska into the Pacific
Northwest. With low-level cold air still in place across
Western Oregon, the precipitation should at least begin as
snow near midday Saturday. How long it stays as snow will
depend on the exact track of the incoming system. It appears
that there will be enough onshore flow, with the passage of
the cold front Saturday afternoon, to change the snow to
rain across the lower elevations of Western Oregon, but the
snow levels will remain low enough for heavy snow in the
coast range and in the Cascades.
A couple of very cold upper-level troughs are forecast to
move over the region Sunday through Wednesday for showery
conditions with very low snow levels. Sticking snow above
500 feet, at times, is a real possibility, with a threat of
wet sticking snow on the valley floor at times.
Wed (23 Jan): Sunny. 18/42
Thu (24 Jan): Increasing Clouds. Chance of Light Snow...Mainly South. 22/37
Fri (25 Jan): Mostly Sunny and Cool. 25/40
Sat (26 Jan): Snow...Likely Changing to Rain in the Afternoon. 28/42
Sun (27 Jan): Showers of Rain or Snow. Possible Significant Accumulations. 33/37
Mon (28 Jan): Showers of Rain or Snow. Possible Significant Accumulations. 32/37
Tue (29 Jan): Showers of Rain or Snow. Possible Significant Accumulations. 32/37
Wed (30 Jan): Showers of Rain or Snow. Possible Significant Accumulations. 32/37
weather at oda.state.or.us
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