[willamette-fcst] Forecast - Friday, October 9th, 2009

Willamette Valley Ag/Burning Forecast willamette-fcst at listsmart.osl.state.or.us
Fri Oct 9 09:04:19 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: 
     Friday, October 9th, 2009 at 9:00am.

Burn Advisory:
     Agricultural burning is allowed.  Suggested burn times are from 12:00pm until 4:30pm.
     Stack burning is not allowed.

Weather Discussion:
     A strong upper-level ridge of high pressure remains over the
     eastern Pacific Ocean with a cool north-northwesterly flow
     aloft over Washington and Oregon.  Satellite imagery shows
     high clouds, assoicated with the northerly jet stream,
     diving south across much of Washington and northeastern
     Oregon, with the main storm energy well east of the region. 
     Skies were mostly clear across the remainder of Oregon,
     except for areas of fog and marine low clouds along the
     coast and in the western valleys.

     The ODA surface analysis showed high pressure over western
     Oregon with weak pressure gradients.  Fair skies and light
     winds allowed temperatures to drop into the 30s and low 40s
     across the Willamette overnight, with Corvallis and Eugene
     dropping into the mid 30s.  The Salem sounding continued to
     show warm air aloft, with the freezing level at 11,000 feet.
     However, cold weather systems are continuing to slide down
     the eastern flank of the ridge and into Montana.

     As the cold weather systems continue southward, into the
     northern Rockies, colder low-level Canadian air will begin
     pouring into eastern Washington this afternoon.  That will
     raise surface pressures east of the Cascades and cut off the
     onshore flow into western Oregon.  Drying northerly winds
     will help to break up the patchy fog and low clouds this
     afternoon with temperatures recovering into the mid and
     possibly upper 60s.

Surface Winds:
     N 0-5 this morning, N 4-10 this afternoon.
Transport Winds:
     NW 5 this morning, N 7 this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 3000 feet.  Ventilation index 21.
High Temperature:
     Salem\'s high temperature today will be near 67.
Humidities:
     Relative humidity drops to 50% by 2pm.
     Minimum relative humidity will be near 45%.
Sunrise/Sunset:
     Salem sunset tonight: 6:37pm; sunrise tomorrow: 7:22am.

Extended Outlook:
     Cold air is forecast to continue to pour into Montana and
     eastern Washington Saturday, which will generate a cold
     easterly outflow from the Columbia Gorge, into the
     Willamette Valley.  That will help clear skies but keep
     temperatures below normal.  Overnight temperatures will be
     especially chilly by Sunday morning, with frost likely in
     wind-sheltered areas.

     The upper-level ridge is forecast to build more directly
     over the west coast by Sunday, with warmer air aloft but
     continued cool low-level offshore flow.  The ridge is
     forecast to be undercut by a strong westerly flow aloft next
     week...opening the door for a series of Pacific storms to
     bring widespread rains onshore.  An upper-level ridge may
     bring some drying late in the week.

Tomorrow (10 Oct):  Mostly Sunny.  Offshore Flow Developing.  36/65

Sun (11 Oct):  Mostly Sunny.  Offshore Flow.  30/65

Mon (12 Oct):  Increasing Clouds.  Chance of Rain Late.  Strong Offshore Flow.  40/63

Tue (13 Oct):  Rain Likely.  Southeast Winds.  46/61

Wed (14 Oct):  Showers Likely.  48/62

Thu (15 Oct):  Mostly Cloudy.  Chance of Showers.  47/64

Fri (16 Oct):  Partly Sunny.  46/65

ODA Meteorologist
weather at oda.state.or.us



More information about the willamette-fcst mailing list