[willamette-fcst] Forecast - Wednesday, February 24th, 2010
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Wed Feb 24 09:18:33 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.
Wednesday, February 24th, 2010 at 9:00am.
Recommended burn times for agricultural burning are from now to 4:00pm.
Straw stack burning is allowed from now until 4:00pm.
A slow-moving frontal system brought steady light rain to
western Oregon Tuesday. CoCoRaHS reports this morning showed
that total rainfall amounts, over the past 24 hours, were
heaviest along the southern Oregon Coast, where between 1.5
and 2 inches were common. Between one-quarter and
three-quarters of an inch of rain fell along the northern and
central coast and in the Willamette Valley, with over an
inch falling in the northern coastal range.
The occluded front finally moved through the Willamette
Valley around midnight and continued to weaken as it pushed
across central and eastern Oregon in the early morning
hours. Precipitation started as rain, at the Cascade pass
level, on Tuesday but changed to wet snow overnight. ODOT
road reports indicated about one-half inch of water-equivalent
precipitation fell at pass level, with over an inch falling
in the higher ski areas. The passes picked up as much as 5 inches
of new snow overngiht with close to 10 inches at the ski resorts.
Rainfall amounts were considerably lighter east of the Cascades,
but most areas picked up at least a few hundredths of an inch. Burns
was one of the wettest location...receiving almost one-half of rain.
We have a moist, but not very unstable, southwesterly flow
aloft this morning, in the wake of the frontal system. That
will keep lots of clouds over the state today, along with some
sunbreaks. Daytime heating will act to increase the chance of
showers somewhat this afternoon, with the chance of showers
continuing into early Thursday.
The freezing level was still over 5000 feet this morning, so the air
mass behind this front was not very cool. The snow level should only
drop to about 3500 feet this afternoon, with a few more inches of wet
snow likely over the Cascade passes. At the surface, the winds turned
southerly, in the wake of the warm occluded front, with coastal and valley
temperatures warming about 5-10 degrees shortly after midnight.
Mid-morning readings ranged from the mid 40s to the low 50s, in most cases
warmer than at any time on Tuesday. For instance, Salem\'s high on Tuesday
was only 44 degrees, with their temperature warming into the upper 40s
shortly after midnight. Continued southerly winds will make for good
ventilation conditions today and will help coastal and western valley
temperatures climb close to normal.
S 5-15 G20 this morning, SSW 5-15 G20 this afternoon.
SSW 20 this morning, SW 20 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 3000 feet. Ventilation index 60.
Salem\'s high temperature today will be near 53.
Minimum relative humidity will be near 71%.
Salem sunset tonight: 5:53pm; sunrise tomorrow: 6:57am.
A transitory ridge of high pressure will bring some drying
on Thursday, with a warm front bringing more rain onshore
Thursday night. The cold front will will encounter a
split-flow jet stream pattern, just off the west coast on
Friday, with the main surge of moisture headed south into
California. Enough energy will swing over Oregon, however,
to maintain rainy conditions with higher elevation snow. A
cool upper-level trough will drop snow levels slightly
Saturday, as showers taper off.
A ridge of high pressure is forecast to rebuild over the
west coast late in the weekend, with unseasonably mild
conditions returning to western Oregon Sunday and Monday.
Increasing southwesterly flow aloft will likely bring a weakening
weather system onshore by late Monday. A little stronger series of
weather systems is forecast for later next week, as the jet stream
takes aim more at Oregon, instead of California.
Tomorrow (25 Feb): Mostly Cloudy. Showers Ending. Snow Level 4000 Feet. 41/55
Fri (26 Feb): Rain Likely. Snow Level Near 5000 Feet. 45/55
Sat (27 Feb): Mostly Cloudy. Showers Ending. Snow Level 4000 Feet. 38/53
Sun (28 Feb): Partly Cloudy and Turning Mild. 37/60
Mon (01 Mar): Increasing Clouds. Continued Mild. Freezing Level Near 7000 feet. 38/62
Tue (02 Mar): Rain Likely. Snow Level 5-6000 Feet. 41/54
Wed (03 Mar): Mostly Cloudy. Decreasing Showers. Snow Level 4-5000 Feet. 38/54
weather at oda.state.or.us
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