[willamette-fcst] Forecast - Wednesday, February 3rd, 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.

Issued: 
     Wednesday, February 3rd, 2010 at 9:00am.

Burn Advisory:
     Recommended burn times for agricultural burning are from now to 3:30pm.
     Stack burning is not allowed.

Weather Discussion:
     Satellite imagery showed cloudy skies covering most of
     Oregon and Washington this morning, with areas of showers
     rotating northward over both states.  The freezing level is
     near 5000 feet this morning, so the showers have been
     falling as snow over the Cascade passes, although accumulations have
     been minimal.  Doppler radar showed a fairly impressive band of
     showers rotating northward into south-central Washington, at mid-morning. 
     Another line of showers extended from around Newport to Salem to Eugene
     and was moving northeastward.  With the upper-level low pressure center
     only about 100 miles off the central Oregon coast, the air aloft is
     just cold enough to support possible thundershower development today,
     especially along the coast and over the coastal range.

     The morning ODA surface analysis showed weak offshore
     gradients, in response the the approaching weather system. 
     Easterly winds will likely turn more southerly later today,
     as the offshore low-presure center slowly migrates northward
     along the Oregon coast.  Generally cloudy skies and occasional
     showers will combine with cool air aloft to keep western Oregon
     temperatures mostly in the 40s today, which is normal for early
     February.  Several inches of new snow are possible over the Cascade
     passes and ski areas.  Cooler air aloft will improve ventilation
     conditions today.

Surface Winds:
     ESE 5-10 this morning, SSE 5-15 this afternoon.
Transport Winds:
     SSE 10 this morning, SSE 15 this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 2000 feet.  Ventilation index 30.
High Temperature:
     Salem\'s high temperature today will be near 49.
Humidities:
     Minimum relative humidity will be near 77%.
Sunrise/Sunset:
     Salem sunset tonight: 5:23pm; sunrise tomorrow: 7:28am.

Extended Outlook:
     A transitory ridge of high pressure will bring brief drying
     tonight and early Thursday, before another weather system
     renews the steady rain and higher elevation snow Thursday
     afternoon and night.  Showers will continue into Friday,
     with a split-flow jet steram pattern developing, typical of
     El Nino.  Once again, the real punch of approaching storms
     will be directed south of the state, into California,
     beginning later this week.  It appears as if western Oregon
     may have a few dry days early next week, with continued mild
     temperatures.

Tomorrow (04 Feb):  Rain Developing and Mild.  Snow Level Rising to 4500 Feet.  38/50

Fri (05 Feb):  Mostly Cloudy and Mild.  Chance of Showers.  Snow Level 4000 Feet.  38/54

Sat (06 Feb):  Rain Developing...Mainly South.  Snow Level 4000 Feet.  37/52

Sun (07 Feb):  Areas of AM Fog...Partly Sunny and Mild.  Snow Level 4000 Feet.  37/51

Mon (08 Feb):  Increasing Clouds.  Slight Chance of Rain Late.  Snow Level 4500 Feet.  36/52

Tue (09 Feb):  Mostly Cloudy.  Slight Chance of Rain.  Snow Level 5000 Feet.  40/54

Wed (10 Feb):  Areas of AM Fog...Partly Sunny. 36/52

ODA Meteorologist
weather at oda.state.or.us