[willamette-fcst] Forecast - Wednesday, August 20th, 2008
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Wed Aug 20 07:52:59 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, August 20th, 2008 at 9:00am.
Agricultural burning is not recommended.
Preparatory burning is not allowed.
Propane flaming is not allowed.
Stack burning is not allowed.
An unseasonably strong Pacific storm system spread rain into
Western Oregon Tuesday afternoon that continued through the
night. Rainfall totals along the coast ranged from nearly
an inch at Astoria to about one-third of inch from Newport
and North Bend. In the Willamette Valley, the heaviest
rainfall was also in the north with the north valley getting
about one-quarter of an inch and the south valley about
one-tenth of an inch overnight.
Rain aksi spread east of the Cascades overnight with up to
one-tenth of an inch falling across North-Central and NE
Oregon. Satellite imagery showed generally cloudy skies
over all of Washington and Oregon this morning. Doppler
radar showed considerable coverage of rainfall across
Washingtonand the northern third of Oregon. A line of
showers, associated with the surfacecold front, was pushing
through the Willamette Valley with a break in the rain
showing up over the northern coast range.
The cold front was moving across the Willamette Valley at
mid-morning and will push east of the Cascades this
afternoon. There will likely be a let-up in the rain, and a
few sunbreaks, in the wake of the cold front later this
morning. However, a strong upper-level trough will bring
vigorous showers to Western Oregon this afternoon through
most of Thursday with rainfall totals across the valley
likely tripling by Thursday night. Temperatures will be at
least 10 degrees below normal today. Highs will only climb
to near 70 with breezy southwesterly winds.
S 10-20 this morning, SW 10-20 this afternoon.
SSW 22 this morning, SW 25 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 2000 feet. Ventilation index 50.
Salem\'s high temperature today will be near 70.
Minimum relative humidity will be near 70%.
Salem sunset tonight: 8:09pm; sunrise tomorrow: 6:22am.
A strong upper-level trough will keep the showers going
through Thursday. Total rainfall amounts, since Tuesday
evening, will likely be one-half to one inch in the north
valley and one-quarter to three-quarters of an inch in the
south valley. Some locations...especially near the Cascade
foothills, may get over an inch.
A flat transitory ridge of high pressure will dry things out
and warm temperatures back to near normal Friday with some
sunshine. The flow aloft will turn southwesterly Saturday
in response to a large upper-level trough in the Gulf of
Alaska. That will bring further warming to Western Oregon,
which will air in the drying of damp fields. The
upper-level trough is forcast to move closer to the
coastline Sunday with increasing southwesterly flow aloft.
That will likely increase the onshore flow Sunday afternoon
with high temperatures staying in the 80s.
A Pacific cold front is forecast to come onshore Monday that
could bring another quarter-inch or more of rain to the
Willamette Valley...especially north. The current timing of
this system is too quick for a burning opportunity Monday,
before the rain sets in, but that will need to be watched
closely. Another flat ridge will dry and warm the air mass
Tuesday with the flow aloft turning soutwesterly again Wednesday.
Tomorrow (21 Aug): Mostly Cloudy. Showers Likely...Mainly North. 56/71
Fri (22 Aug): Mostly Sunny & Warmer. 50/80
Sat (23 Aug): Sunny and Warm. 52/85
Sun (24 Aug): Mostly Sunny. Increasing Clouds Late. 54/85
Mon (25 Aug): Good Chance of Rain and Cooler. 58/72
Tue (26 Aug): Partly Cloudy and Warmer. 50/78
Wed (27 Aug): Mostly Sunny Early...Increasing Clouds with a Chance of Rain Late. 53/81
weather at oda.state.or.us
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