[willamette-fcst] Forecast - Monday, August 18th, 2008
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Mon Aug 18 11:04:43 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 12:00pm.
Agricultural burning is not recommended.
Preparatory burning is not allowed.
Propane flaming is not allowed.
Stack burning is not allowed.
The upper-level ridge that gave us the recent hot spell had shifted
to over Montana late this morning. A very moist and unstable southerly
flow aloft was continuing to generate showers and thundershowers across
Western and Central Oregon.
Doppler radar and satellite imagery showed two distinct lines of
showers and thundershowers late this morning. One stretched from the
Seattle, Wsahington region through North-Central Oregon, and the other
from near Astoria, Oregon southeastward through the Willamette Valley.
The line of showers of the Willamette Valley appeared to be weakening, but
there were still likely a couple of thundershowers left.
There was quite a range of rainfall totals from the storms this morning, due
to the showery nature of the precipitation. Reported rainfall amounts in the
valley, as of 11am, ranged from just .01\" and .03\" at the Eugene and Salem
Airports to .23\" at the Aurora Airport.
The late-morning ODA surface analysis showed a strong thermal low-pressure
center over NE Washington with a thermal trough extending through East-Central
Oregon to South-Central Oregon. Onshore flow was continuing to bring cooler
low-level air into the Willamette Valley. Western Oregon temperatures
were only in the low 60s.
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 this afternoon...maintaining the moist
and unstable southerly flow aloft over Western Oregon this afternoon.
High humidities, damp fields, and continued showers makes open burning
unlikely this afternoon.
SW 5-15 this afternoon.
WSW 08 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 3000 feet. Ventilation index 30.
Salem\'s high temperature today will be near 72.
Minimum relative humidity will be near 64%.
Salem sunset tonight: 8:13pm; sunrise tomorrow: 6:19am.
The flow aloft will turn southwesterly overnight, which will stabilize
the air mass west of the Cascades and push the thundershower threat over
Eastern Oregon. Onshore flow will keep skies mostly cloudy with a continued
chance of a light shower across the Willamette Valley.
An unseasonably strong weather system is forecast to move onshore late
Tuesday afternoon and night for a general rain across Western Oregon.
Depending on the timing of this system, it may create a burning upportunity
Tuesday afternoon, if conditions dry out enough. The valley will likely pick
a general rain Tuesday night and Wednesday morning with showers continuing
through Wednesday. Total rainfall amounts should exceed one-tenth of an inch
and may approach one-half inch.
The flow aloft is forecast to turn northwesterly and begin drying out
Thursday afternoon with a return of more summer-like weather as we head into
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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