[willamette-fcst] Forecast - Friday, February 5th, 2010
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Fri Feb 5 12:07:41 PST 2010
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, February 5th, 2010 at 12:00pm.
Recommended burn times for agricultural burning are from now to 3:30pm.
Straw stack burning is allowed from now until 3:30pm.
...The rules for stack burning have changed. Stack burning
permits must be obtained from ODA Smoke Management Personnel...
A weakening frontal system dropped from about one-tenth to
one-third of an inch of rain across western Oregon
overnight. Between a few hundredths and one-quarter of an
inch of water-equivalent precipitation fell across central
and eastern Oregon. Snow levels were between 4000 and 5000
feet overnight, so areas east of the Cascades saw a mix of
rain and snow. A few inches of new snow fell in the higher
elevations of the Cascades.
The main cloud-shield from this weather system was pushing
across Idaho and into Montana late this morning, with skies
clearing, from west to east, across Oregon. Some rain and
snow showers were still falling over mainly northeastern Oregon,
with dry coditions across western Oregon. It was very mild
overnight, west of the Cascades, where temperatures stayed
mostly in the mid and upper 40s. Temperatures east of the
Cascades varied with elevation. Higher locations stayed near
freezing with occasional light snow, while the lower elevations
stayed above freezing with occasional light rain.
A southwesterly split-flow jet stream pattern, forced by a strong
El Nino event in the tropical Pacific Ocean, will continue the
unseasonalbly mild weather across western Oregon today. The
late-morning ODA surface analysis showed offshore pressure
gradients across western Oregon with southeasterly winds in
the 5-15 mph range. Visible satellite imagery showed mostly
clear skies over western Oregon with only some high clouds.
The next weather system was about 200 miles off the southern Oregon
and northern California coast. With mostly sunny skies and mild air
aloft, late-morning temperatures had already climbed into the mid to
upper 50s across western Oregon. It is possible that daily record
highs could be reached today, with a spring-like afternoon in store.
SE 5-15 this afternoon.
S 18 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 4000 feet. Ventilation index 72.
Salem\'s high temperature today will be near 61 (would tie record high set in 1961).
Minimum relative humidity will be near 45%.
Salem sunset tonight: 5:26pm; sunrise tomorrow: 7:25am.
The next weather system is forecast to split apart, with the
bulk of the moisture moving south, into California, on
Saturday. However, western Oregon will get plenty of clouds
and at least some light rain...mainly south. Weak
southwesterly flow aloft will maintain fairly high snow
levels, for early February, and mild surface temperatures.
A transitory ridge of high pressure will bring drying to
western Oregon Sunday, with continued very mild
temperatures. Snow levels will remain near the Cascade
passes. The next system is forecast to come onshore Monday.
It will also weaken, as it encounters the split-flow jet
stream pattern over Oregon but should be strong enough to
spread some light rain and snow back across the state. Snow
levels are forecast to drop a little lower with this system,
with accumulation snow over the Cascades passes
Another transitory ridge is forecast to move onshore late
Tuesday and Wednesday with precipitation tapering off across
western Oregon. Stronger weather systems are forecast to
come onshore next Thursday and Friday, which could bring
high coastal winds, along with more rain and mountain snow
to western Oregon.
Sat (06 Feb): Rain Likely South. Chance of Rain North. Snow Level 4000 Feet. 37/52
Sun (07 Feb): Showers Ending with Some Sunbreaks. Mild. Snow Level 4000 Feet. 37/54
Mon (08 Feb): Light Rain and Mountain Snow Likely. Snow Level 3-4000 Feet. 36/50
Tue (09 Feb): Mostly Cloudy. Decreasing Chance of Showers. Snow Level 3-4000 Feet. 39/52
Wed (10 Feb): Patchy AM Fog. Partly Sunny. Increasing Clouds in the Afternoon. 34/50
Thu (11 Feb): Rain Likely...Possibly Windy Coast. Snow Level 5000 Feet. 40/53
Fri (12 Feb): Rain Likely...Possibly Windy Coast. Snow Level 4-5000 Feet. 40/51
weather at oda.state.or.us
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