[willamette-fcst] Forecast - Thursday, August 27th, 2009
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Thu Aug 27 09:00:37 PDT 2009
Daily Smoke Management Forecast
Oregon Department of Agriculture
Smoke Management Program
Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts.
Thursday, August 27th, 2009 at 9:00am.
Agricultural burning is not recommended.
Preparatory burning is not allowed.
Propane flaming is not allowed.
Stack burning is not allowed.
A strong upper-level ridge of high pressure, centered over
Idaho, will bring a sunny and warmer day to the interior of
western Oregon today. The Salem sounding this morning showed
further warming alost, since Wednesday afternoon, so high
temperatures will likely warm into the low 90s, after
topping out in the mid to upper 80s Wednesday. Mixing
heights only climbed to around 3000 feet Wednesday and
should be even lower today. The combinatin of light surface
winds, weak southerly flow aloft, and low mixing heights
will make for poor ventilation conditions over the
S 2-6 this morning, SW 4-8 this afternoon.
SSE 4 this morning, SW 5 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 2700 feet. Ventilation index 14.
Salem\'s high temperature today will be near 92.
Relative humidity drops to 50% around 10am.
Minimum relative humidity will be near 20%.
Salem sunset tonight: 7:58pm; sunrise tomorrow: 6:30am.
A weakening Pacific cold front is forecast push into the
strong ridge and swing onshore Friday. It appears as if
this system will have enough moisture to bring some light
rain to the coast by Friday afternoon, with a good chance of
light rain in the Willamette Valley by Friday evening.
Ahead of it, continued southerly flow aloft will likely keep
mixing heights suppressed, over western Oregon, Friday,
making a burning opportunity unlikely. Increasing clouds
and onshore flow should knock 10-15 degrees off of valley
high temperatures Friday, compared to this afternoon.
The incoming weather system is forecast to stall over
Washington and Oregon this weekend...forming an upper-level
low-pressure area over the region...cut off from the main
circulatino pattern. These types of systems tend to be very
slow moving, with this one forecast to drift into eastern
Oregon by Sunday afternoon. That will bring slow drying and
warming to areas west of the Cascades, while maintaining a
good chance of showers over the eastern third of the state.
The upper-level low-pressure area is forecast to finally
push into Idaho Monday with weak south-southwesterly flow
aloft returning to western Oregon during the first half of
next week. That should bring mostly sunny skies and above
normal temperatures to the Willamette Valley. The thermal
trough is forecast to stay east of the Cascades, with weak
onshore flow possibly allowing for some burning opportunities.
Tomorrow (28 Aug): Increasing Clouds and Cooler. Chance of Showers by Evening. 56/78
Sat (29 Aug): Mostly Cloudy. Chance of Showers...Decreasing Late. 55/78
Sun (30 Aug): Becoming Mostly Sunny and Warmer. 53/83
Mon (31 Aug): Mostly Sunny. 54/86
Tue (01 Sep): Mostly Sunny. 54/88
Wed (02 Sep): Mostly Sunny. 54/85
Thu (03 Sep): Mostly Sunny. 53/85
weather at oda.state.or.us
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