[willamette-fcst] Forecast - Tuesday, August 26th, 2008
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Tue Aug 26 07:48:59 PDT 2008
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, August 26th, 2008 at 9:00am.
Agricultural burning is allowed. Suggested burn times are from 12:00pm until 7:00pm.
Preparatory burning is not allowed.
Propane flaming is not allowed.
Stack burning is not allowed.
An upper-level trough combined with daytime heating to
trigger a few afternoon showers Monday...mainly over the
north valley. Skies cleared overnight, allowing
temperatures to drop into the 40s and low 50s across most of
Western Oregon. Cool temperatures and the moist ground
helped areas of fog to form...mainly in the southern
Willamette Valley, near Eugene, and along the coast.
Visible satellite imagery showed only patchy low clouds over
The Salem sounding this morning showed more cooling, from
the surface to about 7500 feet, with warming above 7500
feet. Low-level northeasterly winds, from just above the
surface throught 3000 feet, were helping to dry out the air
mass. The ODA surface analysis showed high pressure
centers over Western Oregon, Western Washington, and Eastern
Oregon with very weak pressure gradients across the
A flat ridge of high pressure will give northwesterly flow
aloft to the region today. Transport winds over the valley
will turn northerly this afternoon, as a thermal trough
attempts to build northward into SW Oregon. The north winds
will drop humidities to near 30% this afternoon, which will
aid in the drying of damp fields. The air aloft is still
quite cool for late August, so even with ample sunshine
today, afternoon temperatures will remain below normal...in
the mid 70s.
A weather system is forecast to move across Southern British
Columbia tonight with the trailing edge of the cold front
increasing the onshore flow across NW Oregon. Some Drizzle
or very light rain is possible along the North Oregon Coast
and in the Northern Willamette Valley Wednesday morning, but
skies should clear Wednesday afternoon, as high pressure
rebuilds over the region.
NW 3-6 this morning, N 5-15 this afternoon.
NNE 5 this morning, N 10 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 4500 feet. Ventilation index 45.
Salem\'s high temperature today will be near 76.
Relative humidity drops to 50% by 1pm.
Minimum relative humidity will be near 32%.
Salem sunset tonight: 7:59pm; sunrise tomorrow: 6:29am.
Flat ridging aloft will dry the air mass Thursday with
transport winds likely turning northerly. A stronger
upper-level trough is forecast to approach the coastline
Friday afternoon with the flow aloft becoming southwesterly.
Transport winds and mixing heights could become favorable
Friday afternoon for open burning of dry fields.
The upper-level trough is forecast to move over the region
Saturday with increasing onshore flow cooling valley
temperatures back into the 70s. Some morning drizzle is
possible...especially along the coast. The flow aloft is
forecast to become northwesterly Sunday with surface and
transport winds likely turning northerly and drying the air
mass. Weak southwesterly flow aloft is forecast for early
next week with near-normal temperatures.
All of the long-range models are indicating a possible
burning opportunity, sometime between Tuesday and Thursday
of next week, as the flow aloft becomes southwesterly and
induces increasing onshore flow.
Tomorrow (27 Aug): AM Clouds...Slight Chance Drizzle North. Afternoon Clearing. 51/76
Thu (28 Aug): Mostly Sunny and Warmer. 50/83
Fri (29 Aug): Mostly Sunny. Increasing High Clouds Late. 53/83
Sat (30 Aug): Morning Clouds. Afternoon Clearing and Cooler. 55/75
Sun (31 Aug): Becoming Mostly Sunny. 49/76
Mon (01 Sep): Mostly Sunny. 49/81
Tue (02 Sep): Mostly Sunny. 50/83
weather at oda.state.or.us
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