[willamette-fcst] Forecast - Wednesday, May 7th, 2008
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Wed May 7 07:59:39 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.
Wednesday, May 7th, 2008 at 9:00am.
Agricultural burning is allowed. Suggested burn times are from 11:00am until 6:30pm.
Straw stack burning is allowed from 11:00am until 6:30pm.
A dry but farily cool upper-level trough slid across Oregon
overnight...dropping the freezing levels over the state,
from 10,000 feet, to around 5000 feet this morning. The
system produced a fair amount of clouds but only a few
sprinkles. East of the Cascades, clouds were giving way to
sunshine this morning with strong onshore flow resulting in
westerly winds of 10-25 mph...even during the usually calm
morning period. Across Western Oregon, strong onshore flow
is spreading a solid deck of marine clouds from well
offshore all the way to the crest of the Cascades. Only the
extreme southern coast and sections of Southwestern Oregon
were seeing any sun-breaks.
Temperatures held up in the mid 40s overnight across Western
Oregon with westerly winds making for a mild morning over
Central and Eastern Oregon. Most of Eastern Oregon stayed
above 40 degrees overnight. One big exception was Redmond,
where the wind settled down enough for the temperature to
briefly drop to 26 degrees (the cold spot in the state).
As the upper-level trough moves into Idaho this afternoon,
weak disturbances will continue to move across Oregon today
in a northwesterly flow aloft. That will maintain the
strong onshore flow across the state. Morning aircraft
reports indicate that the marine clouds over the Willamette
Valley are about 4000 feet thick this morning with areas of
drizzle. At most, only partial late-afternoon clearing is
likely. Valley temperatures will be cooler today with highs
likely staying in the upper 50s. In contrast, skies will be
mostly sunny east of the cascades, but cool west winds will
keep temperatures in the 50s and 60s.
The marine low clouds will likely thicken back up overnight,
west of the Cascades, with areas of drizzle again by
Thursday morning. Temperatures overnight will locally fall
into the mid to upper 30s, but I do not expect frost to be
an issue. East of the Cascades, fair skies will combine
with a cool air mass to allow temperatures to locally drop
below the freezing mark in wind-sheltered valleys.
WNW 5-8 this morning, NW 8-15 this afternoon.
WNW 8 this morning, NW 12-15 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 4000 feet. Ventilation index 32.
Salem\'s high temperature today will be near 59.
Minimum relative humidity will be near 44%.
Salem sunset tonight: 8:26pm; sunrise tomorrow: 5:51am.
Another dry but cool upper-level trough, in the
northwesterly flow aloft, is foreast to move onshore
Thursday and across Oregon Thursday night. That will likely
keep skies mostly cloudy over Western Oregon with strong
onshore flow at the surface holding temperatures mostly in
the 50s. The trough may be strong enough to produce areas
of morning drizzle west of the Cascades and a few sprinkles
or light showers around the state...mainly over the mountains.
After a cool start to the day Friday, a weak ridge of high
pressure should bring partly sunny and warmer weather Friday
afternoon with temperatures recovering to near normal across
the Willamette Valley. A weak cold front is forecast to
approach the coastline Saturday with a chance of light rain
moving onshore by late afternoon. Temperatures will be near
normal, ahead of the front, Saturday and drop back below
normal with a chance of showers Sunday. Showers could
produce sticking snow over the Cascade Passes Sunday, but
significant accumulations are not expected.
Showers are forecast to taper off Monday, as the upper-level
trough pushes east of the region. A warm front is forecast
to bring clouds and perhaps light rain as far south as
Northwestern Oregon Tuesday, but that may be the last threat
of rain for awhile...
The long-range computer models are still indicating the
possibility of much warmer and dry weather for the latter
half of next week...extending into the following weekend,
but that is still a long way out. If we get a large ridge
of high pressure to build over the region, as forecast by
some of the long-range models, then temperatures in the
Willamette Valley would easily climb into the 80s. However,
the Canadian model backed away from this warm solution
today, so I am not going to make that call yet.
Thu (08 May): Chance of AM Drizzle. Slight Chance Showers. Snow Level 4000 Feet. 39/58
Fri (09 May): Becoming Partly Cloudy. 36/63
Sat (10 May): Increasing Clouds. Chance of Showers Late...Mainly North. 40/65
Sun (11 May): Chance of Showers and Cooler. Snow Level Dropping to 3-4000 Feet. 43/58
Mon (12 May): Mostly Cloudy. Afternoon Clearing. 40/63
Tue (13 May): Slight Chance of Rain North. Partly Cloudy South. 45/65
Wed (14 May): Becoming Partly Sunny and Warmer. 46/70
weather at oda.state.or.us
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