[willamette-fcst] Forecast - Tuesday, July 10th, 2007

[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, July 10th, 2007 at 9:00am.

Burn Advisory:
     Agricultural burning is not recommended.
     Preparatory burning is not allowed.
     Propane flaming is not allowed.
     Stack burning is not allowed.

Weather Discussion:
     A strong upper-level ridge extends from the four-courner\'s
     region of the US to the Southern British Columbia Coast this
     morning with very warm air aloft over the Pacific Northwest.
     
     A surface thermal trough has developed west of the Cascades
     and extends from near Medford to off the Northern Oregon
     Coast.  With a full day of July sunshine and offshore
     low-level flow, afternoon temperatures will likely reach or
     exceed the 100 degree mark in the Willamette Valley and the
     90 degree mark along the Northern and Central Oregon Coast. 
     The Southern Coast has low clouds and fog associated with
     onshore surface flow.

     With northeasterly transport winds expected today, there may
     be a brief burning opportnunity, for Western Willamette
     Valley Growers late this morning, before Fire Marshal
     conditions are met. Please contact your permit agent, if
     want to take advantage of this potential burning
     opportunity.


Surface Winds:
     N 6-10 this morning, NNE 10-15 this afternoon.
Transport Winds:
     NE 12-14 this morning, NE 15-20 this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 4000 feet.  Ventilation index 60.
High Temperature:
     Salem\'s high temperature today will be near 101.
Humidities:
     Relative humidity drops to 50% by 10am.
     Minimum relative humidity will be near 21%.
Sunrise/Sunset:
     Salem sunset tonight: 8:59pm; sunrise tomorrow: 5:36am.

Extended Outlook:
     The upper-level ridge will remain over Oregon on Wednesday,
     before beginning to to shift eastward Wednesday night.  The
     associated surface thermal trough will build northward into
     Western Washington, on Wednesday, with an onshore low-level
     flow progressing northward along the Oregon Coast during the
     day.  Some marine air may begin to filter into the Southern
     Willamette Valley late Wednesday, but not before tempertures
     reach or exceed the 100 degree mark for the second straight
     day.

     The upper-level ridge will shift to over Idaho on Thursday,
     with the surface thermal trough moving east of the Cascades
     in the afternoon.  The influx of marine air will be very
     weak, due to southerly flow aloft, and there is also a
     chance of thunderstorm development, so this does not appear
     to be a solid burning opportunity.  We will monitor it.
 
     A stronger southerly to southwesterly flow on Friday brings
     more marine air into the western valleys but also an
     increased threat of thunderstorms. A dry southwesterly flow,
     with onshore surface flow across the state, will develop over the weekend.

Tomorrow (11 Jul):  Sunny and Hot.  65/101

Thu (12 Jul):  Mostly Sunny.  Chance of a Thunderstorm Late.  65/93

Fri (13 Jul):  Chance of Showers and Thunderstorms.  60/85

Sat (14 Jul):  Morning Clouds...Afternoon Sun.  57/81

Sun (15 Jul):  Morning Clouds...Afternoon Sun.  54/85

Mon (16 Jul):  Morning Clouds...Afternoon Sun.  54/84

Tue (17 Jul):  Mostly Cloudy.  Chance of Showers.  56/73

ODA Meteorologist
weather at oda.state.or.us