[willamette-fcst] Forecast - Thursday, June 25th, 2009

Willamette Valley Ag/Burning Forecast willamette-fcst at listsmart.osl.state.or.us
Thu Jun 25 09:14:02 PDT 2009




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: 
     Thursday, June 25th, 2009 at 9:00am.

Burn Advisory:
     Agricultural burning is allowed.  Suggested burn times are from 12:00pm until 8:00pm.
     Preparatory burning is not allowed.
     Propane flaming is not allowed.
     Straw stack burning is allowed from 12:00pm until 8:00pm, from Stayton north, and
     not allowed south of Stayton.

Weather Discussion:
     A well developed cold front swept across Washington and
     Oregon last night, bringing clouds and breezy conditions,
     but not much in the way of rainfall, to western Oregon.  A
     few hundredths of an inch of rain fell along the northern
     Oregon Coast but only trace amounts on the central and south
     coast.  A few sprinkles also fell in the northern Willamette
     Valley, but that was the extent of rainfall, over Oregon,
     with this system.

     In the wake of the cold front, strong onshore flow brought a
     deep layer of cool and moist marnine air into western
     Washington and western Oregon overnight.  Visible satellite
     imagery this morning showed extensive low clouds covering
     all of western Washington and most of western Oregon this
     morning.  With the exception of a few clouds near the cold front,
     along the Idaho border, skies were mostly sunny east of the Cascades. 
     Westerly winds were still gusting over 20 mph across sections
     of northeastern Oregon, but winds had decreased to less than
     10 mph across western Oregon.

     The Salem sounding this morning showed considerable cooling
     of the air mass below 10,000 feet, compared with Wednesday. 
     Temperatures ranged from the mid 50s to the low 60s across
     most of the state at mid-morning.  There is a slight chance
     of sprinkles...mainly over the coastal range and Cascades
     foothills this morning.  Low clouds will give way to partly
     sunny skies across western Oregon this afternoon with
     increasing north-northwesterly surface transport winds. 
     High temperatures will only warm into the low to mid 70s.  

Surface Winds:
     NW 5-13 this morning, NNW 8-15 G20 South this afternoon.
Transport Winds:
     WNW 8 this morning, NNW 14 this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 4300 feet.  Ventilation index 60.
High Temperature:
     Salem\'s high temperature today will be near 72.
Humidities:
     Relative humidity drops to 50% by 12pm.
     Minimum relative humidity will be near 44%.
Sunrise/Sunset:
     Salem sunset tonight: 9:03pm; sunrise tomorrow: 5:27am.

Extended Outlook:
     A weak ridge will shift the jet stream northward, to over
     southern British Columbia, on Friday.  However, continued
     onshore flow will keep some morning clouds over western
     Oregon with afternoon sunshine lifting temperatures close to
     normal. A weather system moving into southern British
     Columbia will push the jet stream back southward again on
     Saturday.  A weak cold front is forecast to move onshore
     Saturday night and across northwestern Oregon early Sunday. 
     It may not be strong enough to produce much shower activity
     this far south, but increasing onshore flow will blanket
     northwestern Oregon with marine low clouds on Sunday and
     cool temperatures back below normal.

     The jet stream will migrate slightly northward, to over
     southern British Columbia, Monday and Tuesday next week. 
     Weak westerly flow aloft will maintain onshore flow at the
     surface, with afternoon sunshine warming temperatures back
     to near or slightly above normal.  A weakening westerly flow
     aloft is forecast by the middle of next week, which may
     decrease the onshore flow and warm temperatures a few more
     degrees.  The threat of precipitation appears minimal for
     Oregon next week, with only a slight chance of light showers
     or drizzle along the north coast.

Tomorrow (26 Jun):  AM Clouds...Becoming Mostly Sunny.  48/75

Sat (27 Jun):  Mostly Sunny and Warmer.  Increasing Clouds Late.  48/82

Sun (28 Jun):  Mostly Cloudy and Cooler.  Slight Chance of Sprinkles North.  53/74

Mon (29 Jun):  AM Clouds.  Partly Sunny in the Afternoon.  49/75

Tue (30 Jun):  AM Clouds.  Mostly Sunny in the Afternoon.  50/78

Wed (01 Jul):  Mostly Sunny.  53/81

Thu (02 Jul):  Mostly Sunny.  54/82

ODA Meteorologist
weather at oda.state.or.us



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