[willamette-fcst] Forecast - Wednesday, May 21st, 2008
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Wed May 21 08:11:35 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.
Wednesday, May 21st, 2008 at 9:00am.
Agricultural burning is allowed. Suggested burn times are from now until 6:30pm.
Straw stack burning is allowed from now until 6:30pm.
A strong cold front swept across the entire Pacific
Northwest Tuesday. It dropped about one-quarter to one-half
of an inch of rain along the northern and central coastal
strip, and about one-quarter of an inch of rain in the
Willamette Valley. The front was strong enough to produce
widespread rain east of the Cascades, with amounts ranging
from a few hundredths of an inch to over one-third of an inch.
The freezing levels over Oregon, which were above 15,000
feet over the weekend, nosedived to near 4500 feet this
morning. A check of the ODOT road cameras revealed fresh
wet snow, along the roadside, over the Cascade Passes this
morning. There was also an extreme temperature drop Tuesday
in the wake of the cold front (on the order of 30 degrees)
across Central and Eastern Oregon. Ontario, near the Idaho
Border, was the warm spot in the Oregon Tuesday...climbing
to 85 degrees just ahead of the cold front early Tuesday
afternoon. Just 4 hours later, the cold front brought
strong winds, locally heavy rain, and thunderstorms, with
the temperature falling into the mid 50s.
Much of Central and Eastern Oregon was buffeted by strong
west winds gusting to near 40 mph on Tuesday with local
blustery conditions continuing this morning. Strong onshore
flow west of the Cascades kept skies mostly cloudy with a
few showers Tuesday. Temperatures only climbed into the low
60s across the Willamette Valley. The ODA surface analysis
this morning showed high pressure nosing into the Southern
Oregon Coast and strong onshore pressure gradients across
all of Oregon.
An upper-level trough over the region will slide southeastward
this afternoon and turn the flow aloft northwesterly over Oregon.
That will keep things on the cool side of normal with strong
onshore flow continuing at the surface. Skies will stay mostly
cloudy across Western Oregon with temperatures struggling to
reach 60 this afternoon. Eastern Oregon will also see mostly
cloudy skies, with highs only in the 50s and low 60s. The air
aloft is quite cold, so daytime heating will act to destabilize
the air mass and lead to the development of scattered showers
across the state this afternoon...mainly near mountains.
The showers and winds will die down overnight, but skies
should remain mostly cloudy over the state. Temperatures
across the Willamette Valley tonight should be a few degrees
colder than the mid to upper 40s we saw this morning. a
relaxing of the winds will combine with a cool air mass to
send much of Central and Eastern Oregon into the 30s
tonight, after holding up mostly in the 40s this morning.
SW 10 this morning, WNW 10-15 G20 this afternoon.
W 13 this morning, WNW 20 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 3500 feet. Ventilation index 70.
Salem\'s high temperature today will be near 58.
Minimum relative humidity will be near 57%.
Salem sunset tonight: 8:42pm; sunrise tomorrow: 5:36am.
A very broad upper-level trough is forecast to center itself
over Nevada this holiday weekend. The counterclockwise
circulation around it will continue to drive enough moisture
into the Pacific Northwest to keep skies partly to mostly
cloudy. The flow aloft will turn northerly, or even
northeasterly at times, which will act to inhibit widespread
rainfall. However, conditions will be moist and unstable
enough to maintain a threat of showers...mainly from the
Cascades eastward and during the afternoons. Temperatures
will warm slightly but remain near to slightly below normal.
The upper-level trough is forecast by computer models to
drift westward, and eventually the California Coast, by Tuesday
of next week. That would put Oregon back under southwesterly flow
aloft, which would increase the shower threat west of the Cascades.
Tomorrow (22 May): Mostly Cloudy. Slight Chance of Showers. A Little Warmer. 43/61
Fri (23 May): Mostly Cloudy. Slight Chance of Showers...Mainly Afternoon. 43/65
Sat (24 May): Partly Cloudy. Slight Chance of Showers...Mainly Afternoon. 43/69
Sun (25 May): Partly Cloudy. Slight Chance of Showers...Mainly Afternoon. 44/70
Mon (26 May): Partly Cloudy. Slight Chance of Showers...Mainly Afternoon. 44/72
Tue (27 May): Mostly Cloudy. Chance of Showers. 46/73
Wed (28 May): Mostly Cloudy. Chance of Showers. 47/73
weather at oda.state.or.us
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