[willamette-fcst] Forecast - Thursday, June 4th, 2009

Willamette Valley Ag/Burning Forecast willamette-fcst at listsmart.osl.state.or.us
Thu Jun 4 09:19:24 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.

...Next Update Scheduled for Friday, June 5th, at 9:00am...

Issued: 
     Thursday, June 4th, 2009 at 9:00am.

Burn Advisory:
     Agricultural burning is allowed.  Suggested burn times are from 11:00am until 7:00pm.
     Straw stack burning is allowed from 11:00am until 7:00pm.

Weather Discussion:
     Daytime heating combined with a continued moist and unstable
     air mass to produce afternoon and evening shower and
     thundershower activity over much of Oregon Wednesday. 
     Thundershowers extended as far north as Salem, west of the
     Cascades, and all the way to the Washington border in
     northeastern Oregon.  The showers were decreasing this morning
     due to cooler surface temperatures, but they were not gone completely.

     Satellite imagery showed clouds circulating over most of
     Oregon, around a broad low-pressure area centered about 100
     miles off the central California coast.  Temperatures were
     mild, again, overnight, with minimums generally in the 50s
     and low 60s on both sides of the Cascades.  Some areas of
     light rain were still falling at mid-morning...from northeastern
     Oregon, across central, to southwestern Oregon.

     The morning sounding over Salem continued to show very
     unstable conditions, so daytime heating will enhance the
     showers across all of Oregon today.  Thunderstorms will
     likely extend northward, to the Washington border, later
     today.  Some of the storms could produce locally heavy
     rainfall and hail.  Slight cooling aloft and considerable
     cloud-cover will hold Willamette Valley highs temperatures
     near 80 degrees today, after climbing to near 90 in the
     north valley Wednesday.

     The surface thermal trough, over western Oregon this
     morning, is forecast to begin shifting east this afternoon,
     in response to the upper-level trough moving onshore into
     california.  Transport winds are forecast to turn
     southwesterly this afternoon, which should improve
     ventilation conditions over the Willamette Valley.  However,
     lightning may develop this afternoon, so seek shelter, if
     you are caught outdoors.  Showers and thundershowers may
     continue through much of the night across western Oregon,
     with a change to more stable conditions beginning Friday.

Surface Winds:
     SSE 3-7 this morning, SW 5-10 this afternoon.
Transport Winds:
     SSE 5 this morning, SW 10 Gusty near showers and t-Storms this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 3200 feet.  Ventilation index 32.
High Temperature:
     Salem\'s high temperature today will be near 80.
Humidities:
     Minimum relative humidity will be near 47%.
Sunrise/Sunset:
     Salem sunset tonight: 8:54pm; sunrise tomorrow: 5:27am.

Extended Outlook:
     The upper-level low-pressure center will move eastward,
     across central California, on Friday.  The flow aloft over
     Oregon will turn northeasterly Friday, with the main area of
     mid and upper-level moisture shifting east of the Cascades
     by Friday afternoon.  Considerable cloud-cover, possible
     showers, and increasing onshore flow will significantly cool
     temperatures west of the Cascades.

     The flow aloft will turn from northeasterly to northwesterly
     Saturday with onshore flow at the surface bringing marine
     low clouds into the western valleys and stabilizing the air
     mass.  The marine layer may become enhanced enough for
     drizzle or light showers across northwestern
     Oregon...especially over the north coast range and along the
     coastal strip.

     A transitory weak upper-level ridge is forecast to keep
     things dry Sunday and Monday, with a series of weak
     upper-level troughs are possibly bringing some morning
     drizzle or light showers to northwest Oregon around the
     middle of next week.  Temperatures may climb slightly above
     normal Sunday and Monday, before dropping back below normal
     around the middle of next week.

Tomorrow (05 Jun):  Decreasing Showers...From NW to SE...Late.  57/71

Sat (06 Jun):  Cloudy AM...Slight Chance of Drizzle.  Partly Sunny PM.  52/70

Sun (07 Jun):  Partly to Mostly Cloudy.  52/73

Mon (08 Jun):  Partly Sunny.  52/75

Tue (09 Jun):  Mostly Cloudy.  Slight Chance of Drizzle or Light Showers.  50/69

Wed (10 Jun):  Mostly Cloudy.  Slight Chance of Light Showers.  50/68

Thu (11 Jun):  Morning Clouds.  Partly Sunny in the Afternoon.  50/71

ODA Meteorologist
weather at oda.state.or.us



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