[willamette-fcst] Forecast - Friday, February 13th, 2009
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Fri Feb 13 11:53:33 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.
.....Next scheduled update is not until Wednesday, February 18th, 2009 at 9am...
Friday, February 13th, 2009 at 12:00pm.
Agricultural burning is allowed. Suggested burn times are from now until 3:30pm.
Stack burning is not allowed.
A weakening cold front brought less than two-tenths of an
inch of rain to the interior valleys of western Oregon last
night and early this morning. Areas of very light rain and
snow pushed east of the Cascades this morning. The bulk of
the moisture from this latest weather system moved south of
the region, into California. Cloudy skies and areas of
light rain kept valley temperatures above freezing overnight
with most minimums in the mid 30s. Late morning temperatures
had warmed to near 40 degrees in the western valleys and
locally into the mid 40s near Portland and along the coast.
The air mass is still quite cold over Oregon. The freezing
levels over Salem and Medford were measured at just 2100 and
1900 feet respectively early this morning. That put the
snow level near 1000 feet this morning. It should only rise
slightly this afternoon. ODOT road cameras showed mostly
wet pavement over the coastal mountain passes. Slush was
reported late this morning over Sunset Summit, on HWY 26
over the coast range. The Cascade and Siskiyou passes looked
they they were improving, as the snow showers let up.
Snowfall amounts in the mountains ranged from a trace in the
northern Cascades to as much as 4 inches over the Siskiyous
of southern Oregon.
The late-morning ODA surface analysis put the low-pressure
center about 100 miles off the northern California coast,
with pressure gradients becoming more northerly across
western Oregon. As the low-pressure center continues to
drift southeastward, pressure gradients will slowly turn
even more northerly across western Oregon this afternoon.
Northerly transport winds are not conducive to good valley
ventilation for stack burning, so it is not allowed today.
Satellite imagery continued to show a significant
cloud-shield circulating northward, around the low-pressure
center off the northern California coast, into Oregon and
most of Washington. Doppler radar indicated a general
decrease in showers across Oregon, with the main jet stream
energy focused well south of the region. The low-pressure
center will continue to weaken and move inland, into
northern California, tonight. Partial clearing overnight
may allow Willamette Valley temperatures to locally drop
below freezing. There will still be a slight chance of a
light shower overnight with the snow level dropping back to
near or below 1000 feet.
N 5-10 this afternoon.
NNE 10 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 2000 feet. Ventilation index 20.
Salem\'s high temperature today will be near 46.
Minimum relative humidity will be near 62%.
Salem sunset tonight: 5:38pm; sunrise tomorrow: 7:14am.
A split-flow jet stream pattern is forecast this weekend
through much of next week. The southern branch of the jet
stream, and main moisture feed, will continue to be directed
into California. A weak upper-level trough will maintain
partly to mostly cloudy skies, cool temperatures and at
least a few showers over Oregon...mainly south. The best
chance of showers will be Sunday through Tuesday with more
of a break during the second half of the week. Another cool
system is forecast to move into the region the following
weekend. Snow levels will rise a little but remain below
the Cascade passes. Willamette Valley temperatures should
remain slightly below normal.
Tomorrow (14 Feb): Mostly Cloudy. Slight Chance of a Shower. Snow Level 1500 Feet. 30/46
Sun (15 Feb): Chance of Showers and Cool. Snow Level Near 2000 Feet. 32/46
Mon (16 Feb): Mostly Cloudy. Chance of Showers. Snow Level 2500 feet. 32/48
Tue (17 Feb): Decreasing Chance of Showers. Snow Level 2-3000 Feet. 33/48
Wed (18 Feb): Slight Chance of Showers. Snow Level 3000 Feet. 33/50
Thu (19 Feb): Partly Cloudy. Slight Chance of Showers. 33/51
Fri (20 Feb): Partly Cloudy. Increasing Chance of Showers Late. 33/52
weather at oda.state.or.us
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