[willamette-fcst] Forecast - Friday, July 20th, 2007
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Fri Jul 20 09:01:24 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 20th, 2007 at 9:00am.
Agricultural burning is not recommended.
Preparatory burning is not allowed.
Propane flaming is not allowed.
Stack burning is not allowed.
A southwesterly flow aloft is steering a very moist weather
system into the Pacific Coastline this morning. Rain was
already falling along the northern coastal strip by 7am,
with doppler radar showing light rain bands pushing over the
coast range and into the western sections of the Northern
This weather system will progress very slowly eastward
today, with light rain likely spreading east and south
across the Willamette Valley this afternoon and evening.
Predicting rainfall amounts from this system is tricky,
because Western Oregon is getting a glancing blow for this
very moist storm. Most of the rain will fall along the
North Oregon Coast and across Western Washington, but the
Willamette Valley could get a quarter of an inch by Saturday
morning. The greatest amounts will be in the northern
Some warming aloft has decreased mixing heights today, but
burning advisory decisions were based on the need for
another drying day, more light rain forecast for this
afternoon, and south-southwesterly transport winds.
Southwesterly surface winds will increase this afternoon, in
the Willamette Valley, as a cold front approaches the Oregon
S 8 this morning, SSW 13 this afternoon.
S 15 this morning, SSW 20 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 4000 feet. Ventilation index 80.
Salem\'s high temperature today will be near 72.
Minimum relative humidity will be near 55%.
Salem sunset tonight: 8:52pm; sunrise tomorrow: 5:46am.
A damp weekend is in store, as a southwesterly flow aloft
steers a couple of very moist weather systems up the Pacific
Coastline. The first system, which will bring rain into the
Willamette Valley This afternoon and evening, will move into
the valley and weaken Saturday, and the second system is
forecast to approach the coastline Sunday morning. Both
storms have tropical origins and are capable of producing a
lot of rain. The lastest computer guidance suggests that
the Northern Willamette Valley could get as much as a
half-inch of rain tonight and Saturday, if the front moves
far enough inland. A tenth to a quarter of an inch in the
northern valley, and a tenth of an inch, or less, in the
southern valley is more likely.
Sunday\'s system not expected to push as far east, with the
valley likely receiving less than a tenth of an inch of
rain. It will weaken considerably, as it moves inland
Monday. By Monday night, an upper level ridge of high
pressure will build enough over the Pacific Northwest to
weaken the storm track. That will bring some drying and
warming, but no prolonged dry or hot weather is forecast.
If significant rain falls between now and then, a couple of
drying days may be required next week, before burning can
Tomorrow (21 Jul): Rain Likely. 59/75
Sun (22 Jul): Cloudy. Light Rain Likely at Times. 60/77
Mon (23 Jul): Mostly Cloudy. Chance of Showers. 60/78
Tue (24 Jul): Partly Sunny. 56/80
Wed (25 Jul): Mostly Cloudy. Slight Chance of Showers. 57/75
Thu (26 Jul): Morning Clouds...Afternoon Sun. 57/80
Fri (27 Jul): Mostly Sunny. 55/83
weather at oda.state.or.us
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