[willamette-fcst] Forecast - Friday, April 24th, 2009

[Willamette Valley Ag/Burning Forecast]

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: 
     Friday, April 24th, 2009 at 9:00am.

Burn Advisory:
     Agricultural burning is allowed.  Suggested burn times are from 11:00am until 6:00pm.
     Straw stack burning is allowed from 11:00am until 6:00pm.

Weather Discussion:
     A cold but fairly dry upper-level trough brought scattered
     showers to western Oregon Thursday with some reports of
     small hail.  After a record-breaking warm start to the
     work-week, temperatures were well below normal with highs
     only in the mid 50s.  The cooler weather spread across the
     entire state during the day.  Temperatures only climbed into
     the 50s, all the way east to the Idaho border, where highs
     Wednesday were in the mid 80s.  Rainfall amounts were
     generally less than a tenth of an inch in the northern
     Willamette Valley, and it stayed dry in the south valley. 
     Less than an inch of new snow fell in the northern Cascades.
      Only trace amounts of rain made it east of the Cascades.

     In the wake of the trough, clearing skies allowed
     temperatures to locally drop below freezing this morning
     across western Oregon and into the teens and 20s across
     central and eastern Oregon.  McMinnville dropped to 30
     degrees this morning and Hillsboro hit 31.  Eugene also
     found the freezing mark.  Baker City was the cold spot east
     of the Cascades with a low of 17 degrees.

     The mid-morning ODA surface analysis showed high pressure
     over western Washington and western Oregon with light
     pressure gradients.  Visible satellite imagery showed patchy
     low clouds in the northern Willamette Valley and over
     southwestern Oregon with mostly clear skies elsewhere west
     of the Cascades.  There were still clouds covering the
     extreme southeast corner of Oregon with fair skies elsewhere
     east of the Cascades.  Temperatures were in the 30s and low
     40s across the state.  Dry northerly flow aloft will bring a
     mostly sunny but cool day to the entire state today with
     below normal temperatures.  Slight warming aloft will help
     valley highs climb to near 60 degrees.

Surface Winds:
     N 3-9 this morning, NNW 5-15 this afternoon.
Transport Winds:
     NE 9 this morning, NNW 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 60.
Humidities:
     Minimum relative humidity will be near 36%.
Sunrise/Sunset:
     Salem sunset tonight: 8:09pm; sunrise tomorrow: 6:10am.

Extended Outlook:
     It will be another locally frosty morning Saturday, with
     mostly clear skies and light winds.  An upper-level
     disturbance is forecast to turn the flow aloft more
     northwestly by Saturday afternoon, which may bring a few
     more clouds back to the region and a slight chance of
     showers over the northern mountains.  The air aloft will
     cool slightly, with the snow level only around 4000 feet.

     A little stronger upper-level impulse is forecast to slide
     mainly across eastern Washington and northeastern Oregon on
     Sunday.  That should bring even more clouds to the region
     with a slight chance of showers extending westward to over
     northwestern Oregon.  Snow levels will remain near 4000 feet
     with a chance of snow showers over the northern Cascades and
     mountains of northeastern Oregon.

     The long-range computer models are showing another cool
     upper-level trough dropping down from Canada, in the
     northerly flow aloft, and setting up camp over the Pacific
     Northwest through at least the first half of next week. 
     That would keep temperatures near to slightly below normal
     and maintain a threat of showers...mainly over the mountains.

Tomorrow (25 Apr):  Partly Cloudy. Slight Chance of Showers. Snow Level 4000 Feet. 34/57

Sun (26 Apr):  Increasing Clouds.  Slight Chance of Showers.  Snow Level 4000 Feet.  35/57

Mon (27 Apr):  Mostly Cloudy.  Slight Chance of Showers.  Snow Level 4500 Feet   35/59

Tue (28 Apr):  Mostly Cloudy.  Chance of Showers.  Snow Level 3500 Feet.  36/58

Wed (29 Apr):  Mostly Cloudy.  Chance of Showers.  Snow Level 4000 Feet.  36/60

Thu (30 Apr):  Partly Cloudy.  Slight Chance of Showers.  36/62

Fri (01 May):  Partly Cloudy.  Slight Chance of Showers.  38/64

ODA Meteorologist
weather at oda.state.or.us