[willamette-fcst] Forecast - Friday, July 6th, 2007
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Fri Jul 6 09:01:29 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.
Friday, July 6th, 2007 at 9:00am.
Agricultural burning is allowed. Suggested burn times are from 12:00pm until 7:00pm.
Stack burning is not allowed.
The strong upper-level ridge of high pressure, that has been
responsible for the hot weather this week, has shifted
eastward into Montana, with a southwesterly flow aloft over
Oregon. The air mass over Southern Oregon is unstable, and
a weak weather disturbance cutting across that region will
likely produce some thunderstorms this afternoon across
South-Central and Southwest Oregon. The remainder of the
state will be dry with increasing onshore surface
The ODA surface analyis this morning showed the thermal
trough had shifted to near the Idaho border, with onshore
flow across all but extreme Eastern Oregon. That will
spread cooler marine air across the state today. High
temperatures will be 5-10 degrees cooler today in the
Willamette Valley, with sunny skies. Central Oregon will
cool about 10 degrees from the 100+ readings on Thursday.
Eastern Oregon will be the last place to see the cooling,
with some eastern valley locations still topping 100 degrees
today, after record-breaking heat on Thursday.
The sounding over Salem this morning showed cooling
thoughout the lowest 10,000 feet of the atmosphere, and more
mid-level cooling is forecast today. That will lift mixing
heights to at least 4500 feet this afternoon. Stack burning
is not allowed, however, due to northerly gradients.
NNW 7-10 this morning, NNW 10-15 this afternoon.
N 12 this morning, N 15 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 4500 feet. Ventilation index 68.
Salem\'s high temperature today will be near 82.
Relative humidity drops to 50% by 2pm.
Minimum relative humidity will be near 35%.
Salem sunset tonight: 9:01pm; sunrise tomorrow: 5:33am.
It looks like it will be a fabulous weekend weather-wise
across the state. A dry and stable westerly flow aloft will
prevail over the weekend, with onshore surface gradients
helping to keep temperatures near normal statewide.
Another strong upper-level ridge will build from Eastern
Nevada into Southern British Columbia early next week,
bringing a return of the heat to the Pacific Northwest.
Surface gradients will become more northerly across Oregon
on Monday with possible thermal trough development in the
Willamette Valley by Tuesday.
An upper-level low pressure area is also forecast to
position itself off of the California Coastline next week,
which will circulate mid and high-level moisture into Oregon
for an increasing thunderstorm threat. The whole pattern is
forecast to shift eastward Thurday and Friday, with strong
southerly flow aloft over Oregon and high thundershower
Tomorrow (07 Jul): Morning Clouds...Sunny. 51/80
Sun (08 Jul): Morning Clouds...Sunny. 49/82
Mon (09 Jul): Sunny. 52/86
Tue (10 Jul): Mostly Sunny & Hot. 56/92
Wed (11 Jul): Partly Cloudy, Muggy & Hot. Slight Chance of a Thundershower. 59/94
Thu (12 Jul): Mostly Cloudy and Muggy. Good Chance of Thundershowers. 60/88
Fri (13 Jul): Mostly Cloudy and Much Cooler. Chance of Showers. 57/72
weather at oda.state.or.us
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