[willamette-fcst] Forecast - Friday, September 18th, 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.

Issued: 
     Friday, September 18th, 2009 at 8:40am.

Burn Advisory:
     Agricultural burning is allowed.  Suggested burn times are from 2:00pm until 6:00pm.
     Preparatory burning is not allowed.
     Propane flaming is not allowed.
     Straw stack burning is allowed from 2:00pm until 6:00pm.

Weather Discussion:
     High pressure, centered over northeastern Oregon, is
     resulting in a dry offshore flow and clear skies across most
     of Oregon this morning. There were patchy areas of low
     clouds and fog along the coast and in the Willamette Valley.
     Clearing skies allowed temperatures to drop into the mid
     40s this morning across much of the Willamette Valley.

     Warm air aloft, weak offshore flow, and a full day of
     late-summer sunshine will combine to warm temperatures into
     the low to mid 80s this afternoon across the Willamette
     Valley. Light northeasterly winds will back to
     west-northwesterly late this afternoon, in response to an
     approaching cold front.

Surface Winds:
     NE 3-8 this morning, WNW 5-10 by late this afternoon.
Transport Winds:
     NE 10 this morning, WNW 10 by late this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 3500 feet.  Ventilation index 35.
High Temperature:
     Salem\'s high temperature today will be near 85.
Humidities:
     Relative humidity drops to 50% around 11am.
     Minimum relative humidity will be near 29%.
Sunrise/Sunset:
     Salem sunset tonight: 7:17pm; sunrise tomorrow: 6:56am.

Extended Outlook:
     A cold front is forecast to swing onshore Saturday, with the
     bulk of the rain pushing into southern British Columbia and
     Washington.  Light rain will spread as far south as western
     Oregon, with the coast likely picking up around one-quarter
     of and inch and the Willamette Valley around one-tenth of an
     inch.  The greatest totals will be in the north. Showers
     will quickly taper off, in the wake of the cold front,
     Saturday evening, with areas of fog forming by Sunday morning.

     An unseasonably strong upper-level ridge is forecast to
     build over the west coast next week (the first week of
     autumn).  Increasing offshore flow will combine with sunny
     skies to send temperatures well above normal.  Tuesday
     through Thursday will likely be the warmest period, with
     record highs possible in the Willamette Valley.  The
     long-range models do not agree on how long the early autumn
     heat-wave will last.  A cool-down could begin as early as
     next Friday, with some of the forecast models keeping
     temperatures very warm through the following weekend.

Tomorrow (19 Sep):  Light Rain Likely...Mainly North.  Clearing Late.  55/72

Sun (20 Sep):  Areas AM Fog...Becoming Sunny and Warmer.  Offshore Flow Developing.  47/76

Mon (21 Sep):  Sunny and Very Warm.  NE Winds.  52/91

Tue (22 Sep):  Sunny.  Record Warmth Possible.  NE Winds.  54/94

Wed (23 Sep):  Sunny.  Record Warmth Possible.  NE Winds.  55/96

Thu (24 Sep):  Sunny and Continued Very Warm.  54/90

Fri (25 Sep):  Mostly Sunny...Possibly Turning Cooler.  51/83

ODA Meteorologist
weather at oda.state.or.us