[willamette-fcst] Forecast - Wednesday, March 18th, 2009
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Wed Mar 18 09:02:39 PDT 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.
Issued:
Wednesday, March 18th, 2009 at 9:00am.
Burn Advisory:
Agricultural burning is allowed. Suggested burn times are from 11:00am until 4:30pm.
Straw stack burning is allowed from 11:00am until 4:30pm.
Forecast Today: Mostly Cloudy and Mild. Salem high near 60.
Weather Discussion:
Showers tapered off across northwest Oregon Tuesday evening,
but skies remained cloudy overnight, in response to a warm
front moving into northwest Washington. Rainfall amounts
Tuesday ranged from about one-quarter of an inch along the
north coast to only a few hundredths of an inch in the
southern Willamette Valley. Temperatures generally stayed
in the low 40s overnight, across western Oregon, with a few
spots dipping into the upper 30s. Pressure gradients
relaxed overnight, and valley winds became calm.
The ODA surface analysis and satellite imagery showed a cold
front moving into northern Vancouver Island, British
Columbia and trailing offshore to about 300 miles off the
northern Oregon Coast. A warm front was producing rain as
far south as the central Washington Coast with cloudy skies
covering Washington and most of Oregon. Weak upper-level
ridging over Oregon is forecast to lift the warm front into
northern Washington and southern British Columbia this
afternoon, with the cold front slowly sagging into
northwestern Washington late in the day. Light rain could
spread as far south as the northern Oregon Coast this
morning and inland into western Washinton. The interior of
western Oregon will likely stay dry, although skies should
remain mostly cloudy.
Warmer air aloft pushed the freezing level over Medford to
8000 feet early this morning (up from 4900 feet Tuesday
morning). The freezing level over Salem had not climbed as
much and was measured at 4500 feet this morning. The air
aloft should continue to warm today, with the freezing level
over northern Oregon rising to about 6000 feet. Light
southerly winds and warmer air aloft should help
temperatures approach 60 degrees across the Willamette
Valley this afternoon...especially south.
Surface Winds:
SE 0-5 this morning, SSW 3-7 this afternoon.
Transport Winds:
SSW 7 this morning, SSW 7 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 5000 feet. Ventilation index 35.
High Temperature:
Salem\'s high temperature today will be near 60.
Humidities:
Minimum relative humidity will be near 51%.
Sunrise/Sunset:
Salem sunset tonight: 7:22pm; sunrise tomorrow: 7:17am.
Extended Outlook:
A cold front will weaken as it sags southward, across
northwestern Oregon, Thursday. That will maintain mostly
cloudy and mild conditions with some light rain possible at
times...mainly in the north valley. The front will act to
maintain good ventilation conditions across western Oregon
with south-southwesterly transport winds. A stronger system
is forecast to swing onshore Friday afternoon, with snow
levels dropping back below the Cascade passes by Friday evening.
An upper-level trough will swing onshore Saturday, but the
main jet stream energy will be focused south of the region,
over California. Skies should stay mostly cloudy over Oregon
with numerous showers and continued farily low snow levels.
Showers should taper off Sunday, as the upper-level trough
moves eastward into the Rockies.
The long-range computer models have greatly differing
solutions beginning early next week, so confidence in the
forecast beyond Sunday is low. A slight north or south
shift in the forecast jet stream position can make a huge
difference in our weather this time of year. Next week
could end up being quite mild and mostly dry or on the damp
side. Western Washington stands a much better chance of
being wet for much of next week, but even that is not
certain at this time.
A transitory ridge may hold on through most of Monday, but
it appears that a cold front will sag south far enough to
bring some rain to western Washington and a chance of rain
to northwestern Oregon Tuesday and Wednesday.
Thu (19 Mar): Mostly Cloudy. Chance of Rain...Mainly North. Snow Level 6000 Feet. 40/59
Fri (20 Mar): Rain and Mountain Snow. Snow Level Dropping to 4-5000 Feet. 44/54
Sat (21 Mar): Showers with Mountain Snow. Snow Level 3-4000 Feet. 40/53
Sun (22 Mar): Decreasing Showers. Snow Level 3000 Feet. 37/52
Mon (23 Mar): Partly Sunny. Freezing Level Rising to 5000 feet. 35/58
Tue (24 Mar): Mostly Cloudy. Chance of Rain...Mainly North. Snow Level 6000 Feet. 40/58
Wed (25 Mar): Mostly Cloudy. Chance of Rain...Mainly North. Snow Level 6000 Feet. 42/58
ODA Meteorologist
weather at oda.state.or.us
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