[willamette-fcst] Forecast - Thursday, July 5th, 2007
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Thu Jul 5 09:01:54 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.
Thursday, July 5th, 2007 at 9:00am.
Agricultural burning is allowed. Suggested burn times are from 11:00am until 7:00pm.
Stack burning is not allowed.
A strong upper-level ridge of high pressure is giving the
Pacific Northwest sunny skies and well above normal
temperatures. The one exception is along the Pacific Coast,
where an increasing onshore flow is producing areas of low
clouds and . The ridge axis is slowly shifting eastward and
was centered from Eastern Idaho into Central Montana this
morning. Near record high tempertures are forecast today
for Central and Eastern Oregon, with many areas climbing
over 100 degrees. A weak onshore surface flow will cap
temperatures in the lower 90s for the Willamette Valley
A general cool-down is expected to begin Friday, as the
upper-level ridge continues to slide eastward. A weak
weather disturbance will push into Southern British Columbia
Friday, with onshore surface gradients increasing across
Western Oregon. Coastal low clouds may briefly penetrate
into some interior valley locations Friday morning with
Willamette Valley afternoon temperatures cooling to the mid
80s. Marine air will also begin spilling into Central and
Eastern Oregon Friday, resuling in brisk westerly winds
along with somewhat cooler conditions.
N 5 this morning, N 8-12 this afternoon.
N 10 this morning, N 10-15 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 4200 feet. Ventilation index 42.
Salem\'s high temperature today will be near 92.
Relative humidity drops to 50% by 1pm.
Minimum relative humidity will be near 30%.
Salem sunset tonight: 9:01pm; sunrise tomorrow: 5:33am.
The upper-level ridge that was responsible for the very warm
weather this week will shift east of the region over the
weekend. That will give way to a weak westerly flow aloft
and continued dry conditions for the Pacific Northwest.
Typical summertime onshore surface gradients will bring a
return of near-normal temperarures across Oregon.
Long-range computer models forecast the building of another
upper-level ridge over the region, but this time it is
expected to extend from Nevada northward to the Southern
British Columbia Coastline. That will cause surface
gradients to become more northerly across Oregon on Monday
with temperatures climbing above normal in the Willamette
We may have some thermal trough development in the
Willamette Valley by Tuesday, but the long-range models do
not agree on this feature, so my confidence is low at this
time. We are likely to see another warm-up, but the hottest
temperatures may, once again, stay east of the Cascades.
All of the models show the thermal trough shifting east of
the Cascades Thursday or Friday, with a significant
cool-down and a threat of showers or thunderstorms.
Tomorrow (06 Jul): Sunny. 56/84
Sat (07 Jul): Sunny. 52/82
Sun (08 Jul): Sunny. 51/83
Mon (09 Jul): Sunny. 53/86
Tue (10 Jul): Sunny. 54/92
Wed (11 Jul): Sunny. 58/93
Thu (12 Jul): Chance of thundershowers. 56/82
weather at oda.state.or.us
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