[willamette-fcst] Forecast - Monday, November 2nd, 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.

NOON UPDATE

Issued: 
     Monday, November 2nd, 2009 at 1:00pm.

Burn Advisory:
     Agricultural burning is not recommended.
     Stack burning is not allowed.

Weather Discussion:
     A broad and flat upper-level ridge is slowly building over
     Oregon, with a strong westerly jet stream over Washington. 
     A weak weather system was spreading clouds, and some rain,
     across northwestern Washington, at midday, with the trailing
     cold front extending southward to about 100 miles off the
     northern Oregon Coast. Ahead of the cold front, visible
     satellite imagery showed mostly clear skies across
     southwestern Washington and western Oregon.

     The ODA surface analysis showed high pressure centered over
     eastern Oregon, with southeasterly pressure-gradients across
     western Washington and weak gradients over most of western
     Oregon.  Winds were mostly light and variable.  After starting
     off near the freezing mark, with areas of fog and low clouds,
     some sunshine had helped Willamette Valley temperatures recover
     into the upper 40s and low 50s by midday.

     The cold front, to our northwest, is forecast to continue to
     weaken, as it pushes into northwestern Washington this
     afternoon and evening.  Some sprinkles may extend as far
     south as the extreme northern Oregon Coast.  Otherwise, dry
     conditions are forecast to continue today, with some
     sunshine warming temperatures in to the upper 50s
     (near-normal for early November).  Light transport winds
     and low mixing heights will make for poor ventilation conditions.

Surface Winds:
     Var 0-5 this afternoon.
Transport Winds:
     N 5 this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 1700 feet.  Ventilation index 9.
High Temperature:
     Salem\'s high temperature today will be near 58.
Humidities:
     Minimum relative humidity will be near 49%.
Sunrise/Sunset:
     Salem sunset tonight: 4:59pm; sunrise tomorrow: 6:54am.

Extended Outlook:
     The upper-level ridge of high pressure is forecast to rebuild
     over Oregon and Washington Tuesday and Wednesday, with increasing
     offshore flow at the surface. That will result in cool mornings,
     with areas of fog and low clouds, but plenty of afternoon sunshine.
     Daytime highs should climb slightly above normal.

     The ridge is forecast to shift east of the region Thursday,
     with increasing southwesterly flow aloft opening the door
     for a fairly potent weather system to come onshore Thursday
     night and Friday.  A cold upper-level trough will move onshore
     over the weekend...lowering the snow level down to the Cascade passes.
     Another cold front is forecast to roll onshore next Monday night.

Tomorrow (03 Nov):  Areas of AM Fog and Low Clouds.  Afternoon Sunshine.  North Winds.  34/60

Wed (04 Nov):  Areas of AM Fog and Low Clouds.  Afternoon Sunshine.  North Winds.  36/63

Thu (05 Nov):  Increasing Clouds.  Chance of Rain Late.  40/60

Fri (06 Nov):  Rain.  48/56

Sat (07 Nov):  Showers and Cool.  Snow Level Dropping to 3500 Feet.  44/54

Sun (08 Nov):  Mostly Cloudy.  Chance of Showers.  Snow Level 3500 Feet.  41/54

Mon (09 Nov):  Increasing Clouds.  Chance of Rain Late.  Snow Level 6-7000 Feet.  41/54

ODA Meteorologist
weather at oda.state.or.us