[willamette-fcst] Forecast - Tuesday, August 18th, 2009
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Tue Aug 18 08:48:38 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.
...State Fire Marshal Conditions will likely be met by mid-afternoon...
Tuesday, August 18th, 2009 at 8:45am.
Agricultural burning is not recommended.
Preparatory burning is not allowed.
Propane flaming is not allowed.
Stack burning is not allowed.
A strong ridge of high pressure was centered just offshore
this morning. The air mass aloft is very warm and will allow
for the intense August sun to warm valley temperatures to
near-record highs this afternoon. The mid-morning ODA
surface analysis showed a strong thermal trough extending
from the northern California/southern Oregon coast
northeastward, through the Willamette Valley, into
south-central Washington. Northeasterly transport winds may
allow for open burning of fields on the extreme western side
of the south valley, late this morning, if low-level winds
are not too strong, by the time mixing heights climb above
2000 feet. Other open burning is highly unlikely today.
After peaking in the upper 80s and lower 90s Monday
afternoon, valley minimums only dipped into the the uper 50s
and low 60s this morning. The Salem sounding showed further
warming this morning, so highs should climb into the mid to
upper 90s today...possibly setting some new daily records.
Like yesterday, the combination of high temperatures,
increasing northerly winds, and low humidities will likely
put much of the valley into State Fire Marshal Conditions by
Visible satellite imagery showed only a shallow layer of low
clouds along the immediate coastline, which should evaporate
by this afternoon, with increasing northerly winds. Even
some of the beaches may locally warm to 80 degrees today,
with much warmer temperatures just inland. Only a few high
clouds were spreading over the remainder of Oregon this
morning, in a weakening northerly flow aloft. A full day of
sunshine will warm temperatures east of the Cascades into
the 80s and 90s.
NNE 5-15 this morning, NNE 8-15 G25 south this afternoon.
NNE 12 this morning, NNE 17 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 3000 feet. Ventilation index 51.
Salem\'s high temperature today will be near 98.
Minimum relative humidity will be near 20%.
Salem sunset tonight: 8:13pm; sunrise tomorrow: 6:19am.
The strong upper-level ridge of high pressure is forecast to
slide eastward, to over Washington and Oregon on Wednesday.
The surface thermal trough will remain over the Willamette
Valley, with light winds and triple-digit highs likely. Many
daily high temperature records are in jeopardy. High temperatures
and low humidities will likely put most of the valley into State
Fire Marshal Conditions again Wednesday afternoon.
The upper-level ridge is forecast to move over Idaho
Thursday, with increasing southwesterly flow aloft over
western Oregon. Some onshore flow, at the surface, will
likely develop Thursday afternoon...cooling temperatures
about 10 degrees and possibly creating a burning opportunity.
Increasing southwesterly flow aloft, and onshore flow at the
surface, will continue the cooling trend across western
Oregon on Friday. There could also be a burning opportunity
Friday afternoon, if too much marine air hasn\'t already
invaded the valley by that time.
A weak trough is forecast to bring a deeper layer of marine
air into the Willamette Valley by Saturday but little to no
rainfall. Onshore flow is forecast to continue Sunday through
Tuesday with little to no rainfall and seasonal temperatures.
Tomorrow (19 Aug): Sunny and Hot. 64/101
Thu (20 Aug): Mostly Sunny and not as Hot. 64/90
Fri (21 Aug): Mostly Sunny and Cooler. 56/85
Sat (22 Aug): AM Clouds. PM Sunshine. 53/81
Sun (23 Aug): AM Clouds. PM Sunshine. 54/84
Mon (24 Aug): Partly Cloudy. 54/86
Tue (25 Aug): Partly Cloudy. 54/82
weather at oda.state.or.us
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