[willamette-fcst] Forecast - Tuesday, April 6th, 2010

Tue Apr 6 09:11:40 PDT 2010

Daily Smoke Management Forecast

Oregon Department of Agriculture
Smoke Management Program
Weather Outlook and Field Burning Advisory for Willamette Valley Growers and Fire Districts.

     The daily Willamette Valley Agricultural Weather Forecast will become a seasonal product,
     as of Friday April 16th. The last broadcast and email of this forecast will be Thursday,
     April 15th. This product will return as the \"Willamette Valley Field Burning Weather
     Forecast,\" issued daily via email and broadcast on WPOZ 585, beginning Thursday July 1st.

Issued: 
     Tuesday, April 6th, 2010 at 9:00am.

Burn Advisory:
     Recommended burn times for agricultural burning are from now until 5:30pm.
     Stack burning is not allowed.

Weather Discussion:
     A compact storm developed just off the northern Oregon coast
     Monday, with a strong cold front moving across northwestern
     Oregon Monday afternoon.  The storm produced strong winds
     and local downpours. South winds gusted to 70 mph along the
     northern and central Oregon coast and to between 40 and 50
     mph across the Willamette Valley.  Salem and Forest Grove
     both recorded peak gusts of over 50 mph (54 mph and 53 mph
     respectively) shortly after 4 p.m.  There were some downed
     trees and power outages from the storm.  Up to an inch
     of rain fell along the coast, with locally just over
     one-third of an inch falling in the Willamette Valley.

     Even with the strong southerly winds, cold air aloft held
     high temperatures near 50 degrees Monday afternoon.  Salem
     and Eugene both recorded a high of just 49 degrees...more
     than 10 degrees below normal.  Shower activity continued
     overnight, with strong onshore flow enhancing the showers
     over the western slopes of the northern Cascades.  4-8
     inches of new snow fell overnight at the ski areas.  3-6
     inces of snow fell over the Cascade passes overnight, with
     the snow level near 2500 feet.  ODOT road cameras showed
     snow-packed road surfaces over the Cascade passes this
     morning, where temperatures were only in the mid 20s.

     Southerly winds slowly decreased overnight but stayed strong
     enough to keep the atmosphere well-mixed.  Coastal and
     valley temperatures stayed mostly in the 40s overnight, even
     though the air aloft is very cold.  The freezing level was
     measured over Salem this morning at just 3400 feet.  Doppler
     radar showed showers continuing to circulate onshore and
     across northwestern Oregon this morning, in a westerly flow
     aloft.  Mid-morning temperatures were mostly in the low to
     mid 40s.  Southerly winds had decreased significantly, with
     occasional gusts to near 20 mph.

     A building ridge of high pressure will turn the flow aloft
     northwesterly this afternoon and begin to stabilize the air
     mass over western Oregon.  That should lead to some
     sunbreaks, with the showers ending by this evening.  Slight
     warming aloft and peeks at the sun should help temperatures
     climb into the low to mid 50s this afternoon.  Partial
     clearning will allow valley temperatures to drop into the
     mid to upper 30s overnight.  However, a weak warm front will
     keep some clouds, and a slight chance of rain, over the
     northwestern corner of the state.

Surface Winds:
     S 7-15 G20 this morning, SW 5-15 this afternoon.
Transport Winds:
     SW 20 this morning, W 15 this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 4500 feet.  Ventilation index 90.
High Temperature:
     Salem\'s high temperature today will be near 53.
Humidities:
     Minimum relative humidity will be near 57%.
Sunrise/Sunset:
     Salem sunset tonight: 7:46pm; sunrise tomorrow: 6:42am.

Extended Outlook:
     Wednesday looks dry and warmer, with the possible exception
     of a weak warm front bringing some light rain to extreme
     northwestern Oregon Wednesday morning.  Temperatures could
     recover to near normal Wednesday afternoon, as skies
     continue to clear.      

     The break in the weather will be brief, with another strong
     cold front forecast to come onshore early Thursday.  An
     upper-level trough will keep a chance of showers over the
     region Friday.  We may see a little warming on Saturday,
     ahead of the next upper-level trough that is forecast to
     come onshore Sunday.  Cool and showery conditions will
     likely last into early next week, with continued
     unseasonably low snow levels.  With the exception of
     tomorrow, temperatures will likely remain below normal
     through the extended forecast period.

Tomorrow (07 Apr):  Becoming Partly Sunny and Warmer.  37/61

Thu (08 Apr):  Rain, Blustery, & Cooler.  Snow Level Dropping to 3000 Feet.  42/51

Fri (09 Apr):  Chance of Showers.  Snow Level 3-4000 Feet.  34/53

Sat (10 Apr):  Partly Cloudy.  Chance of Showers.  Snow Level 4-5000 Feet.  33/59

Sun (11 Apr):  Increasing Showers.  Cooler.  Snow Level 4000 Feet.  38/56

Mon (12 Apr):  Showers Likely.  Cooler.  Snow Level 3-4000 Feet.  38/53

Tue (13 Apr):  Showers Likely.  Continued Cool.  Snow Level 3-4000 Feet.  38/53

ODA Meteorologist
weather at oda.state.or.us