[willamette-fcst] Forecast - Friday, October 9th, 2009
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Fri Oct 9 09:04:19 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:
Friday, October 9th, 2009 at 9:00am.
Burn Advisory:
Agricultural burning is allowed. Suggested burn times are from 12:00pm until 4:30pm.
Stack burning is not allowed.
Weather Discussion:
A strong upper-level ridge of high pressure remains over the
eastern Pacific Ocean with a cool north-northwesterly flow
aloft over Washington and Oregon. Satellite imagery shows
high clouds, assoicated with the northerly jet stream,
diving south across much of Washington and northeastern
Oregon, with the main storm energy well east of the region.
Skies were mostly clear across the remainder of Oregon,
except for areas of fog and marine low clouds along the
coast and in the western valleys.
The ODA surface analysis showed high pressure over western
Oregon with weak pressure gradients. Fair skies and light
winds allowed temperatures to drop into the 30s and low 40s
across the Willamette overnight, with Corvallis and Eugene
dropping into the mid 30s. The Salem sounding continued to
show warm air aloft, with the freezing level at 11,000 feet.
However, cold weather systems are continuing to slide down
the eastern flank of the ridge and into Montana.
As the cold weather systems continue southward, into the
northern Rockies, colder low-level Canadian air will begin
pouring into eastern Washington this afternoon. That will
raise surface pressures east of the Cascades and cut off the
onshore flow into western Oregon. Drying northerly winds
will help to break up the patchy fog and low clouds this
afternoon with temperatures recovering into the mid and
possibly upper 60s.
Surface Winds:
N 0-5 this morning, N 4-10 this afternoon.
Transport Winds:
NW 5 this morning, N 7 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 3000 feet. Ventilation index 21.
High Temperature:
Salem\'s high temperature today will be near 67.
Humidities:
Relative humidity drops to 50% by 2pm.
Minimum relative humidity will be near 45%.
Sunrise/Sunset:
Salem sunset tonight: 6:37pm; sunrise tomorrow: 7:22am.
Extended Outlook:
Cold air is forecast to continue to pour into Montana and
eastern Washington Saturday, which will generate a cold
easterly outflow from the Columbia Gorge, into the
Willamette Valley. That will help clear skies but keep
temperatures below normal. Overnight temperatures will be
especially chilly by Sunday morning, with frost likely in
wind-sheltered areas.
The upper-level ridge is forecast to build more directly
over the west coast by Sunday, with warmer air aloft but
continued cool low-level offshore flow. The ridge is
forecast to be undercut by a strong westerly flow aloft next
week...opening the door for a series of Pacific storms to
bring widespread rains onshore. An upper-level ridge may
bring some drying late in the week.
Tomorrow (10 Oct): Mostly Sunny. Offshore Flow Developing. 36/65
Sun (11 Oct): Mostly Sunny. Offshore Flow. 30/65
Mon (12 Oct): Increasing Clouds. Chance of Rain Late. Strong Offshore Flow. 40/63
Tue (13 Oct): Rain Likely. Southeast Winds. 46/61
Wed (14 Oct): Showers Likely. 48/62
Thu (15 Oct): Mostly Cloudy. Chance of Showers. 47/64
Fri (16 Oct): Partly Sunny. 46/65
ODA Meteorologist
weather at oda.state.or.us
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