[willamette-fcst] Forecast - Thursday, June 18th, 2009
Willamette Valley Ag/Burning Forecast
willamette-fcst at listsmart.osl.state.or.us
Thu Jun 18 09:00:56 PDT 2009
Daily Smoke Management Forecast
Oregon Department of Agriculture
Smoke Management Program
Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts.
Issued:
Thursday, June 18th, 2009 at 9:00am.
Burn Advisory:
Agricultural burning is allowed. Suggested burn times are from 11:30am until 7:30pm.
Preparatory burning is not allowed.
Propane flaming is not allowed.
Straw stack burning is allowed from 11:30am until 7:30pm.
Weather Discussion:
A weak and transitory upper-level ridge of high pressure
will bring dry and slightly warmer conditions to Oregon
today. The one exception will be possible areas of morning
drizzle along the coast and western slopes of the coast
range. Visible satellite imagery showed marine low clouds
blanketing western Washington and most of western Oregon at
mid-morning. The low clouds extended south to about Cape
Blanco on the southern Oregon Coast. Inland, low clouds
covered the entire Willamette Valley and stretched south, to
the southern border of Douglas County, into southwestern
Oregon. Skies were mostly clear east of the Cascade crest
across both Washington and Oregon.
The ODA surface analysis showed weak high pressure building
into the central Oregon Coast with another high pressure
center over northeastern Oregon. Onshore flow extended from
the Oregon Coastl eastward into Idaho. Westererly winds
were less than 10 mph across western Oregon but increased to
around 20 mph across sections of northeast and eastern
Oregon. Temperatures dropped mostly into the 50s overnight
across western Oregon with cooler 40s and 50s east of the
Cascades. Redmond, in central Oregon, was the cold spot in
the state this morning with a minimum of 40 degrees.
The Salem sounding this morning showed slight cooling,
compared with Wednesday, below 5500 feet and warming above,
due to the building upper-level ridge over the region.
Warming aloft will help to shallow the marine layer enough
to promote a little more sunshine this afternoon than on
Wednesday. That will likely boost western Oregon
temperatures into the mid 70s, after topping out in the low
70s Wednesday. Surface and transport winds will be mainly
westerly this afternoon, making for favorable ventililation
conditions for both agricultural and stack burning.
Surface Winds:
W 3-8 this morning, W 5-12 this afternoon.
Transport Winds:
SW 4 this morning, W 10 this afternoon.
Atmospheric Ventilation Conditions:
Maximum mixing height today will be near 5500 feet. Ventilation index 55.
High Temperature:
Salem\'s high temperature today will be near 75.
Humidities:
Relative humidity drops to 50% by 1pm.
Minimum relative humidity will be near 45%.
Sunrise/Sunset:
Salem sunset tonight: 9:02pm; sunrise tomorrow: 5:25am.
Extended Outlook:
The weak upper-level ridge over the region will flatten
tonight, with the flow aloft backing from northwesterly to
southwesterly. A little stronger weather system, compared
with the one that moved across Oregon Tuesday, is forecast
to move onshore Friday. That will deepen the cool marine
layer over western Oregon...resulting in more clouds, lower
temperatures, and a pretty good chance of showers. Scattered
showers will spread across the entire state during the day on
Friday, with a chance of thundershowers from the Cascades eastward.
Another system will bring a reinforcing shot of cool and
moist marine air into western Oregon later Saturday and
Sunday, with a renewed chance of showers. An upper-level
trough is forecast to remain over the region during at least
the first half of next week, with temperatures staying below
normal. Onshore flow will maintain considerable morning
clouds along the coast and in the Willamette Valley, but the
shower threat should significantly decrease after Monday.
The onshore flow is forecast to weaken late next week, with
temperatures warming to near or above normal.
Tomorrow (19 Jun): Mostly Cloudy and Cooler. Chance of Showers. 54/70
Sat (20 Jun): Mostly Cloudy. Chance of Showers...Increasing Late. 51/67
Sun (21 Jun): Cloudy and Quite Cool. Scattered Showers. 50/66
Mon (22 Jun): Mostly Cloudy. Slight Chance of Showers. Partial Afternoon Clearing. 48/69
Tue (23 Jun): AM Clouds. Partly Sunny in the Afternoon. A Little Warmer. 49/74
Wed (24 Jun): AM Clouds. Partly Sunny PM. Slight Chance of Showers...Mainly North. 51/73
Thu (25 Jun): AM Clouds...Becoming Mostly Sunny and Warmer. 50/76
ODA Meteorologist
weather at oda.state.or.us
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