[willamette-fcst] Forecast - Monday, April 12th, 2010

[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.

     This daily Willamette Valley Agricultural Weather Forecast will become a seasonal product,
     as of Friday April 16th. The last broadcast and email of this forecast will be Thursday,
     April 15th. It will return as the \"Willamette Valley Field Burning Weather Forecast,\"
     issued daily via email and broadcast on WPOZ 585, beginning Thursday July 1st.

NOON UPDATE

Issued: 
     Monday, April 12th, 2010 at 3:00pm.

Burn Advisory:
     Recommended burn times for agricultural burning are from now until 6:00pm.
     Stack burning is not allowed.

Weather Discussion:
     A broad upper-level trough is centered over southwestern
     Oregon and northern California this afternoon. Most of the
     energy from this system is being directed south of Oregon,
     but an area of significant rain did sweep north, across much
     of western Oregon Sunday night. On the coast, over one-half
     inch of rain fell over much of Curry County, with about
     one-quarter of an inch falling as far north as Coquille.
     Amounts tapered off to around one-tenth of an inch along the
     northern and central coast.  Across the inland valleys of
     western Oregon, rainfall totals ranged from a little less
     than a tenth of an inch, to around one-half inch, from
     Douglas to Multnomah County overnight.

     Much of western Oregon is in the \"eye of the storm,\" so to
     speak, today. Bands of rain are circulating over extreme
     northwestern Oregon, where another two-tenths of an inch
     have fallen in the Astoria area, and along the
     Oregon/California border. Only scattered light showers are
     being reported over most of western Oregon today, with
     numerous sunbreaks. The ODA surface analysis showed very
     light pressure gradients across western Oregon this
     afternoon, and winds were generally variable at less than 10
     mph.  early afternoon temperatures ranged from the upper 40s
     to mid 50s along the coast and mid 50s to around 60 in the
     interior valleys.

     Freezing levels are around 6000 feet today, which will allow
     high temperatures to climb into the low 60s across the
     Willamette Valley this afternoon.  Surface heating will also
     destabilize the atmosphere and lead to scattered showers
     across much of western Oregon later this afternoon and
     evening. Doppler radar has shown a general increase in the
     shower activity since midday...mainly over the coast and Cascade
     ranges, and across southwestern Oregon.  Some of the showers were
     approaching the southern end of the Willamette Valley...being
     driven by a light south-southeasterly flow aloft.  Skies will stay
     partly to mostly cloudy overnight with a continued chance of showers.

Surface Winds:
     Var 5-10 this afternoon.
Transport Winds:
     SSW 8 this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 5000 feet.  Ventilation index 40.
High Temperature:
     Salem\'s high temperature today will be near 63.
Humidities:
     Minimum relative humidity will be near 34%.
Sunrise/Sunset:
     Salem sunset tonight: 7:54pm; sunrise tomorrow: 6:31am.

Extended Outlook:
     The upper-level trough is forecast to eject eastward, into
     the Rockies, tomorrow.  However, the counterclockwise
     circulation around it will continue to spin moisture across
     western Oregon, so the shower threat will not go away.  In
     fact, slight cooling aloft should make for a cooler
     afternoon.

     To top things off, another upper-level trough is forecast to
     set up camp just off the Oregon and northern California coast 
     by late Wednesday, which should increase the southerly flow
     aloft and the chance of showers. We may get a break from the
     showers by the second half of this coming weekend, with valley
     temperatures possibly climbing to near 70 degrees.  However, a
     strong cold front is forecast to come onshore next Monday, with
     a return of cool valley rain and mountain snow.

Tomorrow (13 Apr):  Mostly Cloudy.  Scattered Showers Likely.  Snow Level 4000 Feet.  44/58

Wed (14 Apr):  Increasing Clouds and Chance of Showers PM.  Snow Level 5-6000 Feet.  37/62

Thu (15 Apr):  Mostly Cloudy.  Chance of Showers.  Snow Level 5000 Feet.  38/62

Fri (16 Apr):  Mostly Cloudy.  Scattered Showers Likely.  Snow Level 5-6000 Feet.  42/62

Sat (17 Apr):  Mostly Cloudy. Chance of Showers...Mainly North. Snow Level 5-6000 Feet. 43/64

Sun (18 Apr):  Partly Cloudy.  Slight Chance of Showers.  Snow Level 6-7000 Feet.  44/68

Mon (19 Apr):  Rain Developing. Much Cooler. Snow Level Dropping to 3-4000 Feet.  44/59

ODA Meteorologist
weather at oda.state.or.us