[willamette-fcst] Forecast - Friday, October 30th, 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: 
     Friday, October 30th, 2009 at 12:00pm.

Burn Advisory:
     Agricultural burning is allowed.  Suggested burn times are from now until 4:00pm.
     Straw stack burning is allowed from now until 4:00pm.

Weather Discussion:
     In the wake of Thursday\'s damp warm front, mild southerly
     winds kept temperatures in the mid 50s overnight across
     western Oregon.  The late-morning ODA surface analysis
     continued to show southerly pressure-gradients, with south
     winds gusting to about 20 mph.  Temperatures were mostly in
     the mid to upper 50s under cloudy skies.

     Warming southerly winds slowly made their way eastward,
     across central and eastern Oregon, Thursday afternoon and
     night...changing the light snow to rain in most areas. 
     However, the low-level cold air did not get scoured out of
     the Baker City area, where light snow turned to light
     freezing rain overnight.  By late this moring, the
     temperature had finally risen above the freezing mark (mid
     30s) in Baker City.  Meanwhile, the vast majority of central
     and eastern Oregon had warmed well into the 40s and 50s with
     balmy southwesterly winds.

     An upper-level ridge of high pressure is weakly pushing
     onshore and helping to dry out the very moist air mass. 
     Visible satellite imagery showed low clouds blanketing most
     of Washington and Oregon. Downsloping westerly winds were
     clearing the skies over much of central Oregon.  Doppler
     radar showed areas of sprinkles across extreme northwestern
     Oregon and western Washington.  Hillsboro picked up .01
     inches of rain between 5 a.m. and 11 a.m. this morning, but
     most of the Willamette Valley stayed dry.  Temperatures had
     warmed into the mid to upper 50s by late this morning,
     across western Oregon, and highs this afternoon should climb
     into the low to mid 60s...with a few sunbreaks.  There will
     continue to be a chance of sprinkles in the north valley.

Surface Winds:
     S 5-15 G20 this afternoon.
Transport Winds:
     SSW 20 this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 2000 feet.  Ventilation index 40.
High Temperature:
     Salem\'s high temperature today will be near 64.
Humidities:
     Minimum relative humidity will be near 70%.
Sunrise/Sunset:
     Salem sunset tonight: 6:03pm; sunrise tomorrow: 7:50am.

Extended Outlook:
     A cold front is forecast to bring a pretty good burst of
     rain to western Oregon late tonight through early Saturday
     morning, with one-quarter to one-half inch possible from the
     north coast to the northern Willamette Valley.  The south
     valley will likely receive around one-tenth of an inch or
     less rainfall.  The front will quickly push east of the
     Cascades, by midday, with some showers continuing to roll
     onshore through Saturday afternoon.  The air mass behind
     this front is not very cold, so showers should begin
     tapering off by Saturday evening, with the snow level
     staying above 5000 feet.

     A flat and broad upper-level ridge of high pressure is
     forecast to build into the coastline Sunday, with continued
     drying of the air mass possibly leading to some sunbreaks. 
     A weak weather system may brush the northwestern corner of
     the state, with some light rain, late Monday.  The ridge is 
     forecast to rebuild over the west coast, possibly giving
     Oregon a break from the damp weather for much of next week.
     There is a chance that a weather system will be strong
     enough to bring some rain on Wednesday, with another slated
     to move be, mainly to the north, on Friday.

Tomorrow (31 Oct):  Rain Early...Decreasing Showers in the Afternoon.  52/59

Sun (01 Nov):  Areas of AM Fog.  Partly Sunny.  40/58

Mon (02 Nov):  Areas of AM Fog.  Mostly Cloudy.  Slight Chance of Rain North Late.  38/58

Tue (03 Nov):  Areas of AM Fog.  Partly Sunny in the Afternoon.  40/60

Wed (04 Nov):  Areas of AM Fog.  Mostly Cloudy.  Slight Chance of Rain.  40/60

Thu (05 Nov):  Areas of AM Fog.  Partly Sunny in the Afternoon.  40/60

Fri (06 Nov):  Increasing Clouds.  Chance of Light Rain...Mainly North.  43/57

ODA Meteorologist
weather at oda.state.or.us