[willamette-fcst] Forecast - Friday, October 17th, 2008

[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.

...Updated Burn Advisory For Stack Burning...

Issued: 
     Friday, October 17th, 2008 at 2:30pm.

Burn Advisory:
     Agricultural burning is not recommended.
     Preparatory burning is not allowed.
     Propane flaming is not allowed.
     Stack burning is allowed, north of a line from Jefferson to Scio, from now until 4:30pm.
     Stack burning is not allow south of a line from Jefferson to Scio.

Weather Discussion:
     Foggy skies continued to hold valley temperatures in the upper 50s in the southern
     Willamette Valley at mid-afternoon.  Sunshine had warmed north valley temperatures into the
     mid 60s, which should lift mixing heights above 2000 feet north of a Jefferson to Scio line.
     Pibals from Salem showed northwesterly winds above 2000 feet, so stack burning is allowed
     until 4:30pm for the areas mentioned above.  Skies should begin to clear in the south
     valley later this afternoon, but it will be too late for stack burning there.

     The cold front, originally slated to move into Oregon this evening, has slowed down and was
     spreading rain only across northwest Washington at mid-afternoon with clouds increasing
     across extreme northwest Oregon.  Clouds will increase this evening with a chance of
     sprinkles or very light rain moving into the north valley overnight.  The front is forecast
     to slowly weaken and move south, across the Willamette Valley, Saturday morning with a
     continued chance of drizzle or very light rain.  Total rainfall amounts should be less than
     one-tenth of an inch, so stacks will likely stay dry enough for burning.

Surface Winds:
     Variable 3-6 this afternoon.
Transport Winds:
     N 3-8 south valley...NW 4-8 in the north valley.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 2500 feet.  Ventilation index 20.
High Temperature:
     Salem\'s high temperature today will be near 68.
Humidities:
     Minimum relative humidity will be near 50%.
Sunrise/Sunset:
     Salem sunset tonight: 6:23pm; sunrise tomorrow: 7:32am.

Extended Outlook:
     A transitory upper-level ridge is forecast to move over the region Sunday.  Increasing
     southwesterly flow aloft will send a stronger weather system onshore Monday through early
     Tuesday.  Total rainfall amounts from this system are forecast to range from one-tenth to
     more than one-quarter of an inch, with the greatest amounts in the north valley.

     Another upper-level ridge is forecast for provide a break from the damp weather Tuesday and
     Wednesday with morning valley fog and afternoon sunshine.  A cold front will likely
     bring more rain by Thursday afternoon.  The long-range models are indicating the possibility
     of a strong ridge of high pressure building over the region, beginning Friday, with
     a prolonged period of mostly dry and mild weather lasting into the following week.

Tomorrow (18 Oct):  Mostly Cloudy.  Decreasing Chance of Sprinkles or very Light Rain.  48/63

Sun (19 Oct):  Areas of AM Fog.  Mostly Sunny in the Afternoon.  40/65

Mon (20 Oct):  Rain Developing.  Snow Level Dropping to near 4000 Feet Late.  45/59

Tue (21 Oct):  Areas of AM Fog...Mostly Sunny Afternoon.  39/62

Wed (22 Oct):  Areas of AM Fog...Mostly Sunny Afternoon. Increasing Clouds Late.  39/66

Thu (23 Oct):  Light Rain Likely.  44/59

Fri (24 Oct):  Areas of AM Fog.  Partly Sunny in the Afternoon.  40/62

ODA Meteorologist
weather at oda.state.or.us