[willamette-fcst] Forecast - Wednesday, April 29th, 2009

[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, April 29th, 2009 at 9:00am.

Burn Advisory:
     Agricultural burning is allowed.  Suggested burn times are from now until 6:30pm.
     Stack burning is not allowed.

Weather Discussion:
     A strong upper-level trough brought cool and damp weather to
     the entire Pacific Northwest Tuesday.  Rainfall amounts
     varied greatly due to the showery nature of the
     precipitation.  Some amounts were impressive on both sides
     of the Cascades. Between one-quarter and three-quarters of
     an inch fell along most of the coast and in the Willamette
     Valley with some areas getting around up to an inch.  Around
     one-tenth of an inch of rain was common in southwestern and
     eastern Oregon, although areas of northeastern Oregon picked
     up close to one-half inch.  Snow levels were only at 3000
     feet Tuesday, with 8 inches of new snow reported at Mt. Hood
     Meadows and 2 inches at Mt. Bachelor.  Several inches of
     snow also fell in the mountains of northeastern Oregon.

     Showers continued overnight around the state with morning
     satellite imagery showing cloudy skies covering most of the
     Pacific Northwest.  A circulation center was just off the
     central Oregon Coast, with Doppler radar showing more
     intense showers near that low-pressure center along and just
     off the central coast.  Lighter showers were scattered over
     the Willamette Valley with the bulk of the precipitation
     over the Cascades.  Mid-morning temperatures were in the low
     to mid 40s across western Oregon, with 30s to mid 40s east
     of the Cascades.

     The morning sounding over Salem showed further cooling
     aloft, in response to the cold upper-level trough over the
     region.  The freezing level was only 3400 feet.  The
     upper-level is forecasst to weaken slightly as it drifts
     slowly south and eventually inland tonight.  Daytime heating
     should destabilize the air mass and increase shower activity
     over the region.  Some showers could include small hail or a
     clap of thunder.  High tempertures will, once again, only
     climb into the low to mid 50s west of the Cascades...about
     10 degrees below average.

Surface Winds:
     SE 5-10 this morning, Becoming NE 4-8 late this afternoon.
Transport Winds:
     SE 13 this morning, ESE 8 this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 4500 feet.  Ventilation index 59.
High Temperature:
     Salem\'s high temperature today will be near 55.
Humidities:
     Minimum relative humidity will be near 57%.
Sunrise/Sunset:
     Salem sunset tonight: 8:15pm; sunrise tomorrow: 6:03am.

Extended Outlook:
     The upper-level trough will continue to weaken and move
     east, to over Idaho, Thursday.  Shwers will end west of the
     Cascades with skies becoming partly sunny.  A warmer
     westerly flow aloft will send a weak weather system into
     southern Oregon and northern California Friday with a slight
     chance of light rain moving as far north as the southern
     Willamette Valley Friday aftenoon and night.

     A stronger system is forecast to come onshore by Saturday
     night with rain becoming likely.  Rain will turn to showers
     Sunday.  An even stronger system is slated to move onshore
     Tuesday, in a strengthening west-southwesterly flow aloft. 
     Depending on the track of the low-pressure system, this
     storm make also produce blustery weather along the coast and
     in the Willamette Valley.  Yet another storm is forecast to
     move onshore Wednesday afternoon.

Tomorrow (30 Apr):  Slight Chance of AM Showers.  Becoming Partly Sunny.  36/62

Fri (01 May):  Increasing Clouds and Warmer.  Slight Chance of Rain South Late.  42/69

Sat (02 May):  Mostly Cloudy.  Rain Likely Late.  45/64

Sun (03 May):  Rain Early...Turning to Showers.  47/60

Mon (04 May):  Mostly Cloudy.  Chance of Showers...Mainly North.  42/63

Tue (05 May):  Rain Likely and Possibly Windy.  47/63

Wed (06 May):  Increasing Rain Late.  44/60

ODA Meteorologist
weather at oda.state.or.us