[willamette-fcst] Forecast - Monday, August 18th, 2008
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Mon Aug 18 08:03:48 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.
Monday, August 18th, 2008 at 9:00am.
Agricultural burning is not recommended.
Preparatory burning is not allowed.
Propane flaming is not allowed.
Stack burning is not allowed.
The strong upper-level ridge of high pressure that brought
triple-digit heat to the Willamette Thursday-Saturday of
last week shifted eastward to over over Idaho Sunday.
Increasing moist and unstable southerly flow aloft triggered
shower and thundershower activity across the western half of
Oregon Saturday night and Sunday. The surface thermal
trough, and 100+ temperatures, shifted east of the Cascades
Sunday. Pendleton was the warm spot in Oregon Sunday with a
record shattering high of 108 degrees. The old daily record
was 104 degrees set in 1934. Meanwhile, the increased
cloud-cover and onshore flow held Western Oregon
temperatures into the 80s Sunday afternoon.
The ridge had shifted to over Montana this morning with a
very moist and unstable southerly flow aloft continuing to
produce numerous showers and thundershowers across Western
and Central Oregon. Doppler radar showed large areas of
showers and thundershowers along the central Oregon Coast,
the northern Willamette Valley, and from south-central
Oregon through the northern Cascades this morning. The
storms were being carried northward by the southerly flow
The morning ODA surface analysis showed a strong thermal
low-pressure center over eastern Washington with a thermal
trough extending through central Oregon to Sw Oregon.
Onshore flow was continuing to bring cooler low-level air
into the Willamette Valley. Western Oregon temperatures
were only in the low 60s with numerous showers and a few
Satellite imagery showed cloud bands circulating northward
around an upper-level disturbance, centered near the
southern Oregon Coast. That system will very slowly move
onshore later this afternoon...maintaining the moist and
unstable southerly flow aloft over Western Oregon today.
High humidities, damp fields, and continued showers makes
open burning unlikely this afternoon.
SW 5-15 this morning, WSW 5-15 this afternoon.
SW 10 this morning, SW 10 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 3500 feet. Ventilation index 35.
Salem\'s high temperature today will be near 76.
Minimum relative humidity will be near 56%.
Salem sunset tonight: 8:13pm; sunrise tomorrow: 6:19am.
The flow aloft will turn southwesterly by tonight, which
will stabilize the air mass and push the thundershower
threat east of the Cascades. It will also maintain the cool
onshore flow across Western Oregon.
An unseasonably strong weather system is still forecast to
move onshore late Tuesday afternoon or night for a general
rain across Western Oregon. Depending on the timing of this
system, it may create a burning upportunity ahead of it
Tuesday afternoon, if conditions are dry enough. The valley
will have a good chance of showers Wednesday. The flow
aloft is forecast to turn northwesterly and begin drying out
Tomorrow (19 Aug): Mostly Cloudy. Good Chance of Rain Late. 59/76
Wed (20 Aug): Rain Turning to Showers. 59/70
Thu (21 Aug): Mostly Cloudy. Slight Chance of Showers. 56/71
Fri (22 Aug): Mostly Sunny. 51/80
Sat (23 Aug): Mostly Sunny. 50/85
Sun (24 Aug): Mostly Sunny. 52/85
Mon (25 Aug): Moslty Sunny. 54/86
weather at oda.state.or.us
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