[willamette-fcst] Forecast - Tuesday, September 8th, 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: 
     Tuesday, September 8th, 2009 at 9:00am.

Burn Advisory:
     Agricultural burning is allowed.  Suggested burn times are from 1:00pm until 6:00pm.
     Preparatory burning is not allowed.
     Propane flaming is not allowed.
     Stack burning is not allowed.

Weather Discussion:
     Saturday and Sunday were very cool and wet, across western
     Oregon.  More than one-half inch of rain fell over much of
     the Willamette Valley, and high temperatures only reached
     the mid to upper 60s. Labor Day brought drying and warming
     to the region, with some afternoon sunshine helping
     Willamette Valley highs recover into the low 70s.

     A weak and transitory upper-level ridge of high pressure was
     over western Oregon this morning and will slide eastward,
     across the state, this afternoon. Satellite imagery showed
     patchy areas of fog and low clouds in the Willamette Valley
     at mid-morning with mostly clear skies over the remainder of
     Oregon. The clear skies made for cool temperatures this
     morning, with valley locations dipping well down into the 40s. 
     Hillsboro recorded a minimum of just 42 degrees.  Mostly
     sunny skies will prevail statewide this afternoon, with
     Willmate Valley highs climbing to near-normal (upper 70s).

     Forecast northeasterly transport winds may allow for limited
     open burning of extreme western valley fields, late this
     morning, if fields are dry enough. Open burning is unlikely
     this afternoon, due to damp fields and forecast light
     northerly transport winds.

Surface Winds:
     NE 0-5 this morning, N 5-10 this afternoon.
Transport Winds:
     NNE 8 this morning, N 5 this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 3500 feet.  Ventilation index 28.
High Temperature:
     Salem\'s high temperature today will be near 78.
Humidities:
     Relative humidity drops to 50% around 12pm.
     Minimum relative humidity will be near 27%.
Sunrise/Sunset:
     Salem sunset tonight: 7:36pm; sunrise tomorrow: 6:44am.

Extended Outlook:
     A weak weater system is forecast to move across southern
     British Columbia Wednesday, with the trailing cold front
     likely bringing some light rain to western Washington and a
     chance of rain to northwestern Oregon.  Skies should begin
     clearing Wednesday evening, with a rapidly building ridge of
     high pressure bringing a return of summer-like weather
     during the second half of the week.  A building surface
     thermal trough should turn low-level winds offshore by
     Friday, which could push valley highs into the low 90s. 
     Northeasterly transport winds may provide an opportunity to
     burn western valley fields.

     As the upper-level ridge begins sliding east of the state
     this weekend, southerly flow aloft will increase.  The
     surafce thermal trough is forecast to shift east of the
     Cascades, with increasing onshore flow cooling temperatures
     back closer to normal.  

Wed (09 Sep):  Partly Cloudy South. Mostly Cloudy North with a Slight Chance of Rain.  49/77

Thu (10 Sep):  AM Clouds...Sunny and Warmer in the Afternoon.  North Winds.  51/85

Fri (11 Sep):  Sunny and Very Warm.  55/92

Sat (12 Sep):  Sunny.  54/88

Sun (13 Sep):  Mostly Sunny.  55/82

Mon (14 Sep):  Mostly Sunny.  54/80

Tue (15 Sep):  Mostly Sunny.  53/80

ODA Meteorologist
weather at oda.state.or.us