[willamette-fcst] Forecast - Tuesday, July 31st, 2007
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Tue Jul 31 09:27:14 PDT 2007
Daily Smoke Management Forecast
Oregon Department of Agriculture
Smoke Management Program
Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts.
...Corrected Fire Marshal Restriction Time For Propane Flaming...
Tuesday, July 31st, 2007 at 9:00am.
Agricultural burning is not recommended.
Preparatory burning is allowed from 11:00am until 3:00pm with a 100 acre limit.
Propane flaming is allowed from 11:00am until 3:00pm.
Stack burning is not allowed.
An upper-level ridge of high pressure will briefly build
over the Pacific Northwest today and Wednesday, with sunny
and warmer weather for most of the region. At the surface,
high pressure is building into Southern British Columbia,
Washington, and Northern Oregon, while a thermal trough of
low pressure is strengthening over Northern California and
Nevada. That is resulting in northerly low-level flow
across Western Oregon, which is inhibiting the development
of moring marine clouds in the Willamette Valley.
North winds will increase this afternoon, in the Willamette
Valley, and relative humidities will drop below 30%.
...Fire Marshal Conditions will likely be met around 3pm...
Mixing heights should climb to near 3000 feet by 11am but
will only reach about 4500 feet this afternoon, due to
continued warming aloft. Temperatures will climb into the
mid to upper 80s this afternoon and into the low to mid
90s Wednesday afternoon.
N 8-12 this morning, N 10-15 G20 this afternoon.
NNE 15 this morning, NNE 20 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 4500 feet. Ventilation index 90.
Salem\'s high temperature today will be near 87.
Relative humidity drops to 50% by 11am.
Minimum relative humidity will be near 25%.
Salem sunset tonight: 8:40pm; sunrise tomorrow: 5:57am.
There are no major changes in the long-range forecast. The
upper-level ridge, and associated surface thermal trough,
are still forecast to shift eastward on Thursday, as a
rather strong weather system, for early August, approaches
the coastline. Transport winds will likely shift from
northerly to northwesterly Thursday afternoon and evening,
while the mixing heights rise in advance of the upper-level
trough. The timing of this change is crucial, as to whether
it will create a burning opportunity. We will continue to
monitor the situation and keep you updated.
A cool upper-level trough is forecast to drop over the
Pacific Northwest Friday through the weekend. That will
produce strong onshore flow, cool tempertures, and the
chance for light showers in the Willamette Valley. The
trough pulls out of the region Monday for drying and warming
Tomorrow (01 Aug): Sunny and Hot. 55/93
Thu (02 Aug): Sunny. Increasing Clouds Late. 60/88
Fri (03 Aug): Mostly Cloudy and Cooler. 55/78
Sat (04 Aug): Mostly Cloudy. Chance of Drizzle or Light Showers. 55/73
Sun (05 Aug): Mostly Cloudy. Chance of Drizzle or Light Showers. 55/72
Mon (06 Aug): Morning Clouds...Afternoon Clearing. 53/78
Tue (07 Aug): Morning Clouds...Mostly Sunny. 51/81
weather at oda.state.or.us
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