[willamette-fcst] Forecast - Monday, February 8th, 2010
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Mon Feb 8 09:10:16 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.
Monday, February 8th, 2010 at 9:00am.
Recommended burn times for agricultural burning are from 10:00am to 3:30pm.
Stack burning is not allowed.
...The rules for stack burning have changed. Stack burning
permits must be obtained from ODA Smoke Management Personnel...
After a mostly sunny and unseasonably mild Friday, with
Eugene and Salem both setting new daily record high
temperatures of 62 degrees, light rain returned to western
Oregon on Saturday. Conditions dried out again Sunday,
although skies stayed mostly cloudy. Temperatures remained
above normal over the weekend, with valley highs in the low
to mid 50s. Partial clearing and light winds last night
allowed temperatures to cool into the 30s across most of
western Oregon by early this morning. That led to
widespread fog formation, with visibilities still locally at
or below one-quarter of a mile, along the coast and in the
Willamette Valley at mid-morning.
Visible satellite imagery showed low clouds and fog covering
most of Washington and Oregon this morning. The exception
was over the Cascades of both states, where mostly sunny
skies prevailed. There were also some breaks in the
overcast along the coast and over the coastal range. The
ODA surface analysis showed weak high pressure centered over
and just east of the Willamette Valley, where winds were
mostly calm at mid-morning. That was a light easterly drift
to the wind along the coastal strip. Mid-morning
temperatures, west of the Cascades, ranged from just below
freezing, at Troutdale, to the low 40s in Corvallis and
along much of the Oregon coast.
A westerly split-flow jet stream pattern, forced by a strong
El Nino event in the tropical Pacific Ocean, will continue
the mild early February weather across western Oregon this
week. Infrared satellite imagery showed the main
cloud-band, associated with an approaching weather system,
still about 200 miles offshore, although some middle and
high clouds were already spreading onshore. Daytime heating
will help break up the fog and low clouds across Western
The air aloft remains mild for this time of year, with the
freezing level measured over Salem this morning at 4500
feet. That is warm enough to support valley temperatures
warming into the upper 50s this afternoon, but considerable
fog, low clouds, and lack of wind will likely combine to cap
valley temperatures in the low 50s. Ventilation conditions
will only briefly improve to fair this afternoon, so stack
burning was not allowed.
ESE 0-6 this morning, NE 2-6 this afternoon.
SE 6 this morning, ESE 5 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 2500 feet. Ventilation index 15.
Salem\'s high temperature today will be near 52.
Minimum relative humidity will be near 60%.
Salem sunset tonight: 5:30pm; sunrise tomorrow: 7:21am.
The next weather system will weaken as it encounters the
split-flow in the jet stream just offshore. The bulk of the
moisture is forecast to dive southweastward, into
California, on Tuesday. Some clouds will sweep across
western Oregon tonight and Tuesday but with only a chance of
light rain and higher elevation snow. A transitory ridge of
high pressure should provide a dry and mild Wednesday with
areas of morning fog. Clouds will be on the increase, by
Wednesday evening, as the next in a series of weather
systems approaches the coastline.
A warm front is forecast to bring lots of clouds and a
chance of light rain to western Oregon Wednesday night and
Thursday morning. Snow levels should rise above the passes
Thursday, as warmer air aloft moves over the region. The
trailing cold front is likely to bring some light rain
Thursday night through Friday morning, with snow levels
dropping back to the Cascade passes.
The warm front from the next system will push mainly north of the region on
Saturday. Sunday should be another mild day, ahead of a cold front
forecast to bring more rain to western Oregon Sunday night. A few showers may
linger well into Monday.
Tomorrow (09 Feb): Mostly Cloudy. Chance of Light Rain. Snow Level 4000 Feet. 36/53
Wed (10 Feb): Areas of AM Fog. Partial Clearing...Increasing Clouds Late. 34/52
Thu (11 Feb): Chance of Light Rain. Snow Level Rising to 5-6000 Feet. 41/52
Fri (12 Feb): Rain Likely. Snow Level Dropping to 4000 Feet. 42/53
Sat (13 Feb): Chance of Light Rain...Mainly North. Snow Level 5-6000 Feet. 42/55
Sun (14 Feb): Mostly Cloudy and Mild. Rain Likely Late. 41/56
Mon (15 Feb): Rain Early...Turning to Showers. Snow Level 3-4000 Feet. 36/53
weather at oda.state.or.us
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