[willamette-fcst] Forecast - Thursday, November 5th, 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.

...No Noon Update Today...

Issued: 
     Thursday, November 5th, 2009 at 9:00am.

Burn Advisory:
     Agricultural burning is allowed.  Suggested burn times are from now until 3:00pm.
     Straw stack burning is allowed from now until 3:00pm.

Weather Discussion:
     Satellite imagery showed a weak weather system along the
     Oregon Coast with a much stronger cold front a couple of
     hundred miles offshore.  The first system was already
     bringing some rain and brisk south winds to the north coast.
     Clouds were increasing over the Willamette Valley and
     Doppler radar was showing a few areas of light rain moving
     into the north valley.

     Mid-morning temperatures ranged from the upper 40s in the
     Willamette Valley to the low 60s along the coast, where
     south winds were gusting to over 30 mph. Winds were still
     light in the Willamette Valley.  South winds will increase
     along the coast and across the Willamette Valley today, with
     gusts to 60 mph possible along the coast this evening and to
     about 40 mph in the Willamette Valley.  The valley should
     see only areas of light rain through mid-afternoon, with
     increasing rain this evening and overnight.

     Due to warm air aloft and increasing south winds, valley
     highs should climb to around 60 degrees this afternoon with
     good ventilation conditions for stack burning.

Surface Winds:
     SE 10-20 this morning, S 15-25 G30 this afternoon.
Transport Winds:
     S 20 this morning, S 30 this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 1700 feet.  Ventilation index 51.
High Temperature:
     Salem\'s high temperature today will be near 60.
Humidities:
     Minimum relative humidity will be near 60%.
Sunrise/Sunset:
     Salem sunset tonight: 4:55pm; sunrise tomorrow: 6:58am.

Extended Outlook:
     a strong cold front is forecast to bring more than one-half
     inch of rain to the coast and Willamette Valley overnight,
     along with brisk southerly winds.  Precipitation will turn
     showery on Friday, with the snow level rapidly dropping to
     about 3500 feet in the Cascades.  Expect wintry travel
     conditions over the passes by Friday afternoon.  South winds
     will remain blustery across western Oregon, with numerous
     showers and a slight chance of thunderstorms.

     Another cold front is forecast to come onshore Saturday,
     with snow levels staying below pass levels.  Locally heavy
     snows are expected in the Cascades, with considerable
     coastal and valley rain.  Showers will taper off Sunday, as
     a weak and transitory upper-level ridge moves across the
     region.  Snow levels should remain below the Cascade passes.

     A warmer system is forecast to come onshore late Monday,
     with snow levels initially lifting just above the Cascade
     passes Monday afternoon.  However, a trailing cool
     upper-level trough will quickly drop the snow level back
     below the passes Tuesday and Wednesday, with considerable
     shower activity across all of western Oregon.  Another
     upper-level ridge is forecast to bring some drying next
     Thursday, but that is getting beyond the accuracy range of
     the computer models.

Tomorrow (06 Nov):  Rain Turning to Showers.  Snow Level Dropping to 3500 feet.  48/54

Sat (07 Nov):  Increasing Rain.  Heavy Mountain Snow Likely.  Snow Level 3-4000 Feet.  44/51

Sun (08 Nov):  Decreasing Showers.  Snow Level 4000 Feet.  40/53

Mon (09 Nov):  Rain Developing Late.  Snow Level Rising to 5-6000 Feet.  39/55

Tue (10 Nov):  Showers.  Snow Level 3-4000 Feet.  42/52

Wed (11 Nov):  Showers.  Snow Level 3000 Feet.  41/52

Thu (12 Nov):  Mostly Cloudy.  Slight Chance of Showers...Mainly North.  38/53

ODA Meteorologist
weather at oda.state.or.us