[willamette-fcst] Forecast - Thursday, March 4th, 2010
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Thu Mar 4 09:22:08 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.
Thursday, March 4th, 2010 at 9:00am.
Recommended burn times for agricultural burning are from 12:00pm until 4:00pm.
Straw stack burning is allowed from 12:00pm until 4:00pm.
A split-flow jet stream pattern is continuing to weaken
weather systems, as they approach the Oregon coast...sending
the bulk of the rain and mountain snows south into
California. A fairly potent weather system moved across
California on Wednesday, with lots of clouds by not a lot of
precipitation making it northward over Oregon. Rainfall
totals over the Willamette Valley ranged from just a trace
to nearly one-quarter of an inch. Meanwhile, near the California
border, Medford picked up nearly one-half inch of rain.
The storm pushed eastward, across Nevada, overnight, sending
significant moisture just north of the Oregon border. Rome,
in southeastern Oregon, picked up over one-inch of
water-equivalent precipitation, with ODOT road cameras
revealing snow-covered ground and near-freezing temperatures
there this morning.
Residual moisture, combined with partial clearing overnight,
led to the formation of low clouds and areas of fog across
the western valleys this morning. Visibilities were locally
reduced to less than one-quarter of a mile across much of
the northern Willamette Valley. Overnight temperatures fell
to near the freezing mark in some sections of the Willamette
Valley. Hillsboro was one of the colder spots, with a
minimum of 33 degrees.
Mid-morning satellite imagery showed considerable low clouds
blanketing the interior valleys of western Oregon, with
clearing skies from the coast range westward to the beaches.
High clouds from the next weather system were advancing
towards the coastline. Temperatures ranged from a foggy 37
degrees, in Hillsboro, to a partly sunny 46 degrees in
Eugene. The ODA surface analysis showed high pressure
building into western Oregon with flat pressure gradients
and light winds.
The air aloft is as cold this morning as we have seen in
awhile. The freezing levels were measured over Medford and
Salem at just 3400 and 4700 feet respectively, and ODOT road
cameras showed a light dusting of new snow over the Cascade
passes. A transitory ridge of high pressure will help skies
to at least partially clear across the western valleys this
afternoon, with mostly sunny skies giving way to increasing
high clouds along the beaches. A light south wind will
develop, ahead of the next weather system, helping afternoon
temperatures climb into the mid 50s across the Willamette Valley.
SSE 0-5 this morning, S 3-6 this afternoon.
S 5 this morning, SSW 6 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 3500 feet. Ventilation index 21.
Salem\'s high temperature today will be near 55.
Minimum relative humidity will be near 61%.
Salem sunset tonight: 6:04pm; sunrise tomorrow: 6:43am.
On Friday, a weather system dropping into the region, from
the Gulf of Alaska, will also encounter the split-flow
pattern in the jet stream offshore and move mainly into
California. Some light rain is possible...mainly along the
coast and across southern Oregon. A weak ridge of high
pressure will dry things out for the first half of the
weekend with a little sunshine.
A change to a stormy and cooler weather pattern is forecast
for next week. A cold front should spread rain back onshore
Sunday afternoon, and across western Oregon by Sunday
evening. This system has colder air aloft associated with
it, so snow levels will likely drop to below the Cascade
passes. Showers will taper off Monday, with the lowest snow
levels we\'ve seen in many weeks. After a brief break, early
Tuesday, another cold weather system will bring more valley
rain and much-needed mountain snow Tuesday night and
Wednesday. Yet another system is forecast to bring rain and
blustery conditions onshore Thursday, followed by cooler and
showery weather next Friday.
Fri (05 Mar): Mostly Cloudy. Chance of Rain...Mainly South. Snow Level 4000 Feet. 38/57
Sat (06 Mar): Becoming Partly Sunny and Mild. 37/60
Sun (07 Mar): Rain Developing in the Afternoon. Snow Level Dropping to 3-4000 Feet. 36/53
Mon (08 Mar): Decreasing Showers. Snow Level 2500 Feet. 35/49
Tue (09 Mar): Increasing Clouds. Chance of Rain Late. Snow level 4000 Feet. 31/51
Wed (10 Mar): Rain Turning to Showers. Snow Level Near 3000 Feet. 38/51
Thu (11 Mar): Rain Developing and Turning Blustery. Snow Level Rising To 5000 Feet. 36/52
weather at oda.state.or.us
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