[willamette-fcst] Forecast - Tuesday, March 16th, 2010
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Tue Mar 16 08:16:11 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.
Tuesday, March 16th, 2010 at 9:00am.
Recommended burn times for agricultural burning are from now until 4:30pm.
Straw stack burning is allowed from now until 4:30pm.
It was a mild afternoon on Monday across western Oregon,
with offshore flow bringing the warmest readings to the
northern coast. Astoria recorded a high Monday of 67
degrees and Tillamook hit 68. Highs in the Willamette
Valley were mostly in the low to mid 60s. Aurora was the
warm spot with 66 degrees. Eugene was the cool spot with a
high of 59. Southwesterly flow aloft spread middle and high
clouds over the region last night...making for mild
overnight temperatures. Most of western Oregon stayed in
the 40s this morning. McMinnville was the cool spot with a
minumum of 38 degrees. Normally Willamette Valley minimums
are in the mid to upper 30s for this time of year.
Clouds were beginning to lower and thicken across western
Oregon, by mid-morning, in advance of a weakening cold front
just offshore. Satellite imagery showed a narrow band of
clouds stretching from the southern British Columbia
coastline to the northern California coast and then trailing
offshore to the southwest.
The ODA surface analysis showed increasing southeastery
pressure gradients across western Oregon, ahead of the
approaching cold front. Southerly winds were already gusting
to 30 mph along the coast, at Newport, with light rain just
starting to fall. Rain will spread across the entire
coastline over the next couple of hours and into the
Willamette Valley by early this afternoon. Southerly winds
will increase in the Willamette Valley later this morning.
Mixing of the air mass should help temperatures jump into
the mid, and possibly upper 50s around midday, because the
air aloft is still very warm. The freezing levels over
western Oregon were measured at about 8-10 thousand feet
early this morning.
Cooling aloft and increasing light rain will likely chill
valley temperatures into the lower 50s by late this
afternoon. Rainfall totals should only be about one-tenth
of an inch across the Willamette Valley, with most of the
rain falling between midday and early this evening. Partial
clearing is likely in the wake of the cold front overnight
with just a chance of a shower...mainly north and over the
mountains. The snow level will drop to between three and
four thousand feet by Wednesday morning, with a couple of
inches of fresh snow possible in the Cascades overnight.
SSE 5-15 G20 this morning, SW 10-20 G30 this afternoon.
S 15 this morning, SW 30 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 3000 feet. Ventilation index 90.
Salem\'s high temperature today will be near 56.
Minimum relative humidity will be near 60%.
Salem sunset tonight: 7:20pm; sunrise tomorrow: 7:21am.
The roller-coaster ride in temperatures is likely to
continue during the extended forecast period, with very mild
conditions over the weekend followed by a sharp cool-down
early next week. A cool upper-level trough will maintain
some showers over mainly the northern half of Oregon through
about midday Wednesday. A dry northwesterly flow aloft is
forecast for Thursday, as an upper-level ridge of high
pressure begins building just off the west coast. That will
lead to cool morning temperatures, but afternoon highs
should recover to near or slightly above normal.
The upper-level ridge is forecast to move over Oregon Friday
and Saturday. Offshore surface winds will keep the air mass
dry...leading to a large spread between morning minimums and
afternoon maximums. Mornings may bring areas of frost to
the Willamette Valley. Afternoon highs will be well above
normal, with the warmest temperatures along the coast, on
Friday, and over the inland valleys on Saturday. The ridge
is forecast to slide over Idaho by Sunday afternoon with
increasing southwesterly flow aloft over western Oregon.
Highs on Sunday should be closer to normal, with a cold
front is spreading rain onshore by Sunday night.
Temperatures will likely drop back below normal Monday and
Tuesday with snow levels lowering below the Cascade passes.
Showers will taper off by Tuesday afternoon.
Tomorrow (17 Mar): Chance of a Shower Early...Becoming Partly Sunny in the Afternoon. 37/57
Thu (18 Mar): Cool Start, With Possible Areas of Frost...Becoming Mostly Sunny. 33/59
Fri (19 Mar): Possible Frosty Start...Sunny and Mild in the Afternoon. 31/62
Sat (20 Mar): Cool Morning...Sunny and Very Mild in the Afternoon. 33/65
Sun (21 Mar): Increasing Clouds. Chance of Rain Late. 35/60
Mon (22 Mar): Rain Likely and Much Cooler. Snow Level Dropping to 3000 Feet. 39/52
Tue (23 Mar): Mostly Cloudy. Chance of Showers...Mainly North. 37/54
weather at oda.state.or.us
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