[willamette-fcst] Forecast - Wednesday, July 9th, 2008
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Wed Jul 9 07:54:00 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, July 9th, 2008 at 9:00am.
Agricultural burning is not recommended.
Preparatory burning is not allowed.
Propane flaming is not allowed.
Stack burning is not allowed.
A broad but flat upper-level ridge of high pressure brought
sunny, breezy and very warm weather to Oregon
Tuesday...especially west of the Cascades. Willamette
Valley highs Tuesday climbed into the low 90s and most of
the coastline warmed well into the 70s. It was hot across
SW oregon with Medford topping out at 102 degrees Tuesday
afternoon. Brookings, on the extreme south coast, jumped to
108 degrees with the aid of local downslope winds.
The upper-level ridge is still parked over the Pacfic
Northwest this morning but is expected to flatten a bit
later today in response to a disturbance moving across
Southern British Columbia. In spite of slight cooling aloft
forecast for this afternoon, today should be as warm or
warmer than Tuesday across the interior of Western Oregon.
The early morning Salem sounding was warmer aloft than on
Tuesday morning, with continued northeasterly transport
winds. In addition, surface temperatures are starting out
about 5 degrees warmer this morning across Western Oregon
with minimums generally from the mid 50s to the low 60s. A
couple of the cooler spots were the Corvallis and McMinnville
Airports, with minimums of 54 and 56 degrees respectively.
The ODA surface analysis showed high pressure from Western
Washington through NE Oregon with northerly gradients across
Western Oregon. A thermal trough had nosed into extreme SW
Oregon with northerly winds in the Willamette Valley running
5-10 mph. The north winds should increase to between 10 and
25 mph this afternoon with gusts to near 30 mph in the south
valley. Weak onshore flow had brought a shallow layer of
fog and low clouds onto sections of the northern and central
coast, but sunshine should prevail there by this afternoon.
Skies were clear over the interior of the state.
N 5-15 G20 south valley this morning, N 13-23 G30 south valley this afternoon.
NNE 18 this morning, N 23 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 3500 feet. Ventilation index 81.
Salem\'s high temperature today will be near 94.
Relative humidity drops to 50% by 10am.
Minimum relative humidity will be near 23%.
Salem sunset tonight: 8:59pm; sunrise tomorrow: 5:36am.
The ridge ov high pressure over the Pacific Northwest will
flatten further Thursday, in response to an upper-level
trough cutting across extreme Southern British Columbia.
Cooler air aloft and weak onshore flow will combine to cool
Western Oregon temperatures to near normal. Transport winds
are forecast to stay mostly northerly on Thursday, so
burning opportunities are unlikely with this system.
A transitory ridge is forecast to turn the low-level flow
north-northeasterly again Friday, with valley temperatures
quickly rebounding back to near 90. The latest computer
guidance is suggesting that an even warmer day is possible
Saturday, before the ridge pushes east of the region
Saturday evening. A trough is forecast to increase the
westerly flow aloft late Sunday and Monday. That will turn
the surface flow onshore with marine clouds moving inland by
Monday morning. Temperatures should cool into the mid 80s
Sunday and below normal Monday. There is a slight chance
that the trough will be strong enough to produce drizzle or
light showers Monday morning.
The trough is forecast to move into Eastern Washington
Tuesday with continued onshore flow across Western Oregon.
Transport winds should have more of a westerly component
Monday and Tuesday, which may create burning
opportunities...especially in the north valley. A weak
ridge is forecast to begin building over the region next
Wednesday with the surface flow turning northerly and
Willamette Valley temperatures warming back above normal.
Tomorrow (10 Jul): Mostly Sunny & Cooler. North Wind 10-25 mph. 53/83
Fri (11 Jul): Mostly Sunny and Warmer. North Wind 10-20 mph. 50/90
Sat (12 Jul): Sunny and Hot. 55/94
Sun (13 Jul): Partly Cloudy and Cooler. 53/84
Mon (14 Jul): Morning Clouds...Slight Chance of a Shower. Partly Sunny. 52/76
Tue (15 Jul): Morning Clouds. Slight Chance of an AM Shower. Partly Sunny. 52/78
Wed (16 Jul): Mostly Sunny & Warmer. 52/85
weather at oda.state.or.us
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