[willamette-fcst] Forecast - Wednesday, April 1st, 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: 
     Wednesday, April 1st, 2009 at 9:00am.

Burn Advisory:
     Agricultural burning is allowed.  Suggested burn times are from 10:00am until 5:30pm.
     Straw stack burning is allowed from 10:00am until 5:30pm.

Weather Discussion:
     A strong but fairly dry northwesterly flow aloft directed a
     cold front across Washington and Oregon Tuesday afternoon. 
     It was accompanied by blustery south winds and a brief burst
     of rain, in the Willamette Valley, following by cloudy but
     generally dry weather Tuesday evening.  Rainfall totals west
     of the Cascades were not impressive, with the north coast
     and northern Willamette Valley picking up about one-tenth of
     an inch.  In the south valley, Eugene only got a trace of rain.

     Cold air, in the wake of the front, dropped the freezing
     level to 3700 feet over Salem by late Tuesday afternoon and
     to just 2400 feet by early this morning.  The cold front had
     more jet stream support across central and eastern Oregon,
     with the northern mountains picking up a fair amount of new
     snow. Timberline Lodge received just one inch of new snow,
     but Mt. Hood Meadows picked up 8 inches. Mt Bachelor got 5
     inches of new snow, and Willamette Pass got 2 inches.  The
     mountains of northeast Oregon got hit hard, with Anthony
     Lakes Ski area received 16 inches of new snow.  The front
     also produced strong winds across northeastern Oregon, with
     Pendleton getting gusts to nearly 60 mph.

     Skies remained mostly cloudy overnight with an approaching
     warm front spreading light rain across western Washington
     and northwest Oregon in the pre-dawn hours this morning. 
     Doppler radar and surface reports indicated that light rain
     had spread south to about Corvallis by mid-morning.  Light
     snow had also moved into the northern and central Cascades,
     with pass temperatures in the mid to upper 20s. 
     Considerable middle and high clouds had also spread across
     the northern half of eastern Oregon.

     As the offshore warm front approaches, light rain will
     continue to spread south and east across the state today,
     with the snow level climbing to about 6000 feet by late this
     afternoon.  The ODA surface analysis showed southerly
     gradients beginning to strengthen along the coast, so south
     winds will pick up as the day progresses.  Rainfall amounts
     in the valley could approach one-quarter of an inch by
     tonight.  Cloudy and rainy skies will hold high temperatures
     in the 40s most of the day in the valley with the warmest
     readings likely ahead of the cold front this evening.

Surface Winds:
     S 5-15 this morning, S 10-20 G25 this afternoon.
Transport Winds:
     SSW 15 this morning, SSW 25 this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 2000 feet.  Ventilation index 50.
High Temperature:
     Salem\'s high temperature today will be near 50.
Humidities:
     Minimum relative humidity will be near 74%.
Sunrise/Sunset:
     Salem sunset tonight: 7:40pm; sunrise tomorrow: 6:50am.

Extended Outlook:
     An approaching cold front will increase the rain and
     mountain snow tonight and early Thursday across western
     Oregon, along with the southerly winds.  In the wake of the
     cold front, a cool upper-level trough will bring vigorous
     showers Thursday afternoon with possible small hail.  Heavy
     snow is likely over the Cascade passes.  Showers will taper
     off Friday with continued low snow levels.  

     More spring-like conditions will finally arrive Saturday, as
     a transitory upper-level ridge builds into the coastline. 
     The long-range computer models still disagree as to how long
     the dry weather will last, but it appears that rain may hold
     off until late Sunday. This system should be cold enough to
     bring some snow to the Cascades Monday...mainly south.
     Showers are forecast to linger into Tuesday.  We may get a
     break from the damp weather Wednesday of next week, but
     there is no long-term dry weather pattern forecast by the
     long-range computer models.

Tomorrow (02 Apr):  Rain Turning to Showers.  Snow Level Dropping to 3000 Feet.  42/52

Fri (03 Apr):  Decreasing Showers.  Snow Level 2-3000 feet.  36/53

Sat (04 Apr):  Partly Cloudy and Warmer.  33/62

Sun (05 Apr):  Increasing Clouds.  Chance of Rain late.  Snow Level 5-6000 Feet.  37/61

Mon (06 Apr):  Chance of Rain.  Snow Level Dropping to 4000 Feet.  40/57

Tue (07 Apr):  Mostly Cloudy. Chance of Showers. Snow Level 4000 feet.  38/58

Wed (08 Apr):  Mostly Cloudy.  39/59

ODA Meteorologist
weather at oda.state.or.us