[willamette-fcst] Forecast - Friday, February 6th, 2009
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Fri Feb 6 09:01:06 PST 2009
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 6th, 2009 at 9:00am.
Agricultural burning is allowed. Suggested burn times are from now until 3:30pm.
Stack burning is not allowed.
The massive upper-level ridge of high pressure, that brought
stagnant weather conditions to the Pacific Northwest for
most of January, is finally breaking down. A weather
system, dropping southeastward from the Gulf of Alaska,
helped to kick inland an upper-level low pressure system,
off the California coast. The combination of systems
brought cloudy skies to the region Thursday with light
spreading across western Oregon Thursday evening.
The morning sounding over Salem showed a deep layer of
significant cooling, since Thursday morning. There was
still a weak low-level temperature inversion, from the
surface up to about 1500 feet, but ventilation conditions
have dramatically improved over the region. freezing level
had dropped from 8900 feet Thursday morning to only 4800
feet this morning. ODOT road cameras showed snow beginning
to fall over the Cascade passes this morning with pass
temperatures near freezing. In contrast, clouds and rain
kept valley temperatures warmer overnight, where minimums
were near 40 degrees. The ODA surface analysis showed very
weak pressure gradients across Oregon and Willamette Valley
winds were were light at mid-morning.
Rainfall amounts in the past 24 hours range from about
one-tenth to one-third of an inch across western Oregon.
The weak upper-level trough over the region is forecast to
push far enogh east by this afternoon for the flow aloft to
become northerly and begin drying out. Showers will
decrease across western Oregon this afternoon and evening.
The snow level should drop to about 3000-3500 feet with
several inches of snow possible over the Cascade passes.
Valley temperature will be cooler this afternoon with highs
in the mid to upper 40s. High pressure will begin building
into the coastline with surface winds becoming
north-northwesterly. Partial clearing overnight should
promote fog formation across much of western Oregon with
temperatures dropping into the mid 30s.
N 0-5 this morning, NNW 5-10 this afternoon.
N 3 this morning, N 9 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 1900 feet. Ventilation index 17.
Salem\'s high temperature today will be near 47.
Minimum relative humidity will be near 76%.
Salem sunset tonight: 5:28pm; sunrise tomorrow: 7:24am.
A transitory ridge will likely bring a dry and farily mild
day to the region Saturday. Another weather system is
forecast to bring more rain and mountain snow Sunday
afternoon and night with the snow level dropping to 3000
feet. Showers will continue Monday with very low snow
levels. There may be a brief break early Tuesday, ahead of
the next cool weather system. More cool weather systems are
forecast to sweep across the region later in the week.
Sat (07 Feb): Areas AM Fog. Partly Cloudy and Mild. Freezing Level 5-6000 Feet. 34/51
Sun (08 Feb): Increasing Clouds. Rain Developing PM. Snow Level 3-4000 feet. 32/46
Mon (09 Feb): Showers...Decreasing Late. Snow Level 1500 Feet. 34/45
Tue (10 Feb): Areas AM Fog. Rain Developing in the Afternoon. Snow Level 2000 Feet. 32/45
Wed (11 Feb): Showers...Decreasing Late. Snow Level 1500 Feet. 34/45
Thu (12 Feb): Mostly Cloudy. Increasing Chance of Rain Late. 34/47
Fri (13 Feb): Rain with Mountain Snow. Snow Level 1000 Feet. 34/45
weather at oda.state.or.us
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