[willamette-fcst] Forecast - Wednesday, April 22nd, 2009

Wed Apr 22 09:04:50 PDT 2009

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 22nd, 2009 at 9:00am.

Burn Advisory:
     Agricultural burning is allowed.  Suggested burn times are from now until 6:00pm.
     Straw stack burning is allowed from now until 6:00pm.

Weather Discussion:
     Sunny skies prevailed statewide Tuesday afternoon, with the
     exception of local areas of low clouds and fog along the
     coastal strip.  Highs temperatures were similar to Monday,
     with many daily records tied or broken across state.  Here
     are some of the records set Tuesday afternoon:

     Location        High Tuesday     Previous Record

     Willamette Valley

     Portland Downtown 82 degrees (record 79 set in 1959)

     Portland Airport  82 degrees (record 77 set in 1982)

     Troutdale         82 degrees (record 81 set in 1986)

     Hillsboro         80 degrees (tied record set in 1982)

     Salem             81 degrees (record 80 set in 1918)

     Southwestern Oregon

     Medford           92 degrees (record 88 set in 1986)

     East of the Cascades

     The Dalles        87 degrees (record 85 set in 1986)

     Redmond           84 degrees (tied record set in 1986)

     Pendleton         83 degrees (tied record set in 1956)

     Meacham           72 degrees (tied record set in 1956)

     Baker City        84 degrees (record 82 set in 1986)

     Burns             83 degrees (record 80 set in 1986)

     Rome              86 degrees (record 84 set in 1942)

     The ridge of high pressure that brought the unseasonably
     warm weather had shifted well east of the rgion this morning
     with a vigorous but fairly dry upper-level trough dropping
     southward along the British Columbia Coastline.  The ODA
     surface analysis showed a cold front pushing into the
     Washington Cascades and trailing back across extreme
     northwest Oregon.  Strong onshore flow had deveoped across
     Western and central Washington and was beginning to increase
     across western Oregon.  Pressure gradients were still weak
     across central and eastern Oregon.

     Satellite imagery showed cloudy skies covering most of
     Washington at mid-morning, but the clouds had only
     progressed as far south and east as the northwest corner of
     Oregon.  Most of Oregon was still enjoying sunshine. 
     Temperatures were mostly in the 40s and low 50s statewide. 
     No precipitation was being reported in Oregon, but rain has
     been falling this morning across sections of western
     Washington...including the Seattle area.  Doppler radar was
     not showing much in the was of shower activity south of
     about the central Washington coast.

     Clouds and northwesterly winds will increase, from northwest
     to southeast, across western Oregon today, as the cold front
     slowly pushes southeastward across the region.  Cooler
     onshore flow will drop high temperatures about 20 degrees
     across western Oregon today.  The cooler air will arrive
     later today across eastern Oregon, where high temperatures
     will only be about 10 degrees cooler than they were
     yesterday.  The air mass will slowly moisten with time, with
     an increasing chance of showers later today and
     tonight...especially over the mountains and along the coast.

Surface Winds:
     NW 5-15 this morning, NW 10-15 G20 this afternoon.
Transport Winds:
     N 15 this morning, NW 18 this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 5000 feet.  Ventilation index 90.
High Temperature:
     Salem\'s high temperature today will be near 63.
Humidities:
     Minimum relative humidity will be near 43%.
Sunrise/Sunset:
     Salem sunset tonight: 8:07pm; sunrise tomorrow: 6:14am.

Extended Outlook:
     A potent surface cold front will usher a cuch cooler air
     mass into the state tonight and Thursday...followed by a
     cold but fairly dry northerly flow aloft Friday.  Another
     cool trough is forecast to drop southward over the region
     this weekend, maintaining a chance of showers, mainly over
     the mountains, and below normal temperatures.  Overnight
     minimums could approach the freezing mark across normally
     colder sections of the Willamette Valley beginning Friday
     morning.

     The American long-range computer model shows the flow aloft
     turning northerly and drying out early next week, with a
     building ridge of high pressure bringing back above normal
     temperatures by Tuesday.  However, the Canadian and European
     computer models maintain a cool upper-level trough over the
     Pacific Northwest.  My forecast reflects the warmer forecast
     shown by the American model, since it has been outperforming
     the other models recently.

Tomorrow (23 Apr):  Mostly Cloudy and Cool.  Chance of Showers.  Snow Level 3000 Feet.  36/57

Fri (24 Apr):  Partly Cloudy.  Slight Chance of Showers.  Snow Level 3500 Feet.  33/59

Sat (25 Apr):  Partly Cloudy and Cool.  Chance of Showers.  Snow Level 4000 feet.  34/60

Sun (26 Apr):  Partly Cloudy.  Slight Chance of Showers.  Snow Level 4000 feet.  35/60

Mon (27 Apr):  Mostly Sunny.  35/64

Tue (28 Apr):  Sunny and Warmer.  39/70

Wed (29 Apr):  Sunny and Warm.  42/71

ODA Meteorologist
weather at oda.state.or.us