[willamette-fcst] Forecast - Monday, November 9th, 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: 
     Monday, November 9th, 2009 at 9:00am.

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

Weather Discussion:
     It was a stormy weekend across Oregon, with wind, rain,
     mountain snow, and even a weak tornado. Southerly winds
     gusted to around 30 mph at times in the Willamette Valley
     and to near 40 mph along the coast.  The blustery winds were
     accompanied by more than an inch of rain, both along the
     coast and across the Willamette Valley.  Temperatures were
     near-normal, with highs mostly in the low to mid 50s.

     Heavy snow fell in the northern Cascades, with the ski
     resorts on Mt. Hood picking up as much as 2 1/2 feet of new
     snow.  Snowfall amounts rapidly tapered off to the south,
     with Mt. Bachelor receiving just over a foot of snow and
     Willamette Pass only a few inches.  The Mt Hood passes
     picked up around a foot of snow, with Willamette Pass just
     getting a dusting.

     A rare weak tornado touched down in Lincoln City Friday
     night, with wind speeds estimated between 65 and 85 mph. 
     The tornado\'s destruction path was only about 150 yards long
     and 80 yards wide.  11 homes and 3 cars were damaged, but
     there were no injuries reported.

     There will be no break in the stormy weather today, with
     satellite imagery showing another active cold front about to
     move onshore at mid-morning. Ahead of the front, clouds had
     already spread across the western two-thirds of Oregon, with
     Doppler radar and surface reports showing light to moderate
     rain along the coast...moving into the Willamette Valley. 
     The ODA surface analysis showed tightening southeasterly
     pressure-gradients across western Oregon.  Southesterly
     winds were gusting to about 25 mph from the northern and
     central coast across the northern Willamette Valley. 
     Mid-morning temperatures ranged from the mid 40s to the low
     50s across western Oregon.

     As the cold front comes onshore, later this morning, a brief
     period of strong and gusty winds is possible along the north
     coast, where the National Weather Service has issued a high
     wind warning for gusts to 60 mph.  It will also get quite
     windy along the central coast later this morning.  As the
     cold front moves inland late this morning, the northern
     Willamette Valley will likely have the strongest winds, with
     gusts to around 30 mph possible.  The front will also
     produce a few hours of locally moderate to heavy rainfall,
     before pushing east of the Cascades this afternoon.

     Warmer air ahead of the storm has lifted snow levels to
     above 6000 feet, so the mountain passes will initially get
     rain from this system.  ODOT road cameras showed generally
     just wet pavement over the passes at mid-morning, with
     temperatures well above freezing.  The steady rain will turn
     showery this afternoon, with a few breaks in the clouds
     possible.  Highs will climb into the low to mid 50s, with
     slowly decreasing southerly winds.

Surface Winds:
     SSE 10-20 G30 this morning, S 10-20 G25 this afternoon.
Transport Winds:
     S 30 this morning, SSW 25 this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 1500 feet.  Ventilation index 45.
High Temperature:
     Salem\'s high temperature today will be near 53.
Humidities:
     Minimum relative humidity will be near 63%.
Sunrise/Sunset:
     Salem sunset tonight: 4:50pm; sunrise tomorrow: 7:03am.

Extended Outlook:
     A upper-level trough will slowly approach the coastline
     Tuesday, with a continued moist southwesterly flow aloft
     maintaining a chance of showers across western Oregon.  The
     snow level will lower to the Cascade passes tonight and
     Tuesday.  Showers will increase on Wednesday, as the
     upper-level trough finally swings onshore.  The snow level
     will drop to around 3000 feet, with locally heavy snow
     possible over the Cascade passes.

     A somwwhat drier northwesterly flow aloft is forecast for
     Thursday, with a cold weather system forecast to drop into
     the region, from the Gulf of Alaska, on Friday.  That system
     could produce locally heavy snow, again, over the Cascade
     passes, with the lowest snow levels so far this season.  A
     warm front is forecast to quickly lift snow levels Saturday,
     with a chance of light rain.  Another cold front is forecat
     to come onshore Sunday, but with a warmer westerly flow
     aloft.

Tomorrow (10 Nov):  Mostly Cloudy.  Chance of Showers.  Snow Level 4000 Feet.  42/54

Wed (11 Nov):  Increasing Showers.  Snow Level 3000 Feet.  40/50

Thu (12 Nov):  Mostly Cloudy.  Chance of Showers.  snow level 3000 feet.  38/49

Fri (13 Nov):  Rain and Mountain Snow.  Snow Level Dropping to 2000 Feet.  38/48

Sat (14 Nov):  Mostly Cloudy.  Chance of Light Rain.  Snow Level 4000 Feet.  40/52

Sun (15 Nov):  Rain...Mainly North.  Snow Level 5000 Feet.  44/54

Mon (16 Nov):  Mostly Cloudy.  41/53

ODA Meteorologist
weather at oda.state.or.us