[willamette-fcst] Forecast - Wednesday, March 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, March 3rd, 2010 at 12:00pm.

Burn Advisory:
     Recommended burn times for agricultural burning are from now until 4:00pm.
     Stack burning is not allowed.

Weather Discussion:
     A Pacific frontal system is moving into Oregon and California at midday. Satellite
     imagery shows multiple circulation centers associated with this system.  One
     low-pressure center is just off the coast of Newport, but the main low-pressure
     center is off the northern California coastline.  A band of clouds, arcing around
     the low-pressure centers, covers most of western and central Oregon.

     The jet stream continues to be aimed south of Oregon, with the main punch from this
     system being directed into northern and central California.  Doppler radar was still
     showing some areas of very light precipitation over western and central Oregon, but
     most of the region was cloudy and dry.

     The ODA surface analysis showed light northerly gradients in the northern Willamette
     Valley and light southerly gradients across the south valley, with a weakening frontal
     boundary sitting over the central valley.  Skies should remain mostly cloudy today,
     with sprinkles or very light rain possible at times.  Valley highs will likely be a few
     degrees cooler than on Tuesday, with some light snow above about 4000 feet in the Cascades.

Surface Winds:
     N 3-8 north valley...S 5-10 south valley this afternoon.
Transport Winds:
     NE 5 north valley, SSW 6 south valley this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 2000 feet.  Ventilation index 20.
High Temperature:
     Salem\'s high temperature today will be near 53.
Humidities:
     Minimum relative humidity will be near 66%.
Sunrise/Sunset:
     Salem sunset tonight: 6:02pm; sunrise tomorrow: 6:44am.

Extended Outlook:
     A transitory ridge of high pressure will dry things out on
     Thursday.  The next weather system, on Friday, will also
     encounter the split-flow pattern in the jet stream offshore
     and move mainly into California.  A weak ridge of high
     pressure will likely bring dry and mild conditions for at
     least the first half of the weekend.

     A weak cold front is forecast to come onshore Sunday afternoon,
     which appears as if it will be strong enough to spread some rain
     and higher elevation snow back across western Oregon.  Some
     computer models are indicating a possible change in the weather
     pattern, beginning the middle of next week, that could bring
     some much needed snow to the mountains.

Tomorrow (04 Mar):  Partly Sunny.  35/55

Fri (05 Mar):  Mostly Cloudy.  Chance of Rain...Mainly South.  Snow Level 4000 Feet.  40/55

Sat (06 Mar):  Partly Sunny.  35/58

Sun (07 Mar):  Increasing Clouds.  Chance of Rain PM.  Snow Level 4000 Feet.  37/53

Mon (08 Mar):  Decreasing Chance of Showers.  Snow Level 3-4000 Feet.  37/53

Tue (09 Mar):  Increasing Clouds.  Chance of Rain Late.  36/55

Wed (10 Mar):  Rain Likely...Snow Level Possibly Lowering to Near 3000 Feet.  38/52

ODA Meteorologist
weather at oda.state.or.us