[willamette-fcst] Forecast - Thursday, November 6th, 2008

[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: 
     Thursday, November 6th, 2008 at 9:00am.

Burn Advisory:
     Agricultural burning is allowed.  Suggested burn times are from now until 3:00pm.
     Straw stack burning is allowed from now until 3:00pm.

Weather Discussion:
     A strong warm front brought rainy and cool conditions to
     Western Oregon Wednesday with afternoon temperatures mostly
     in the upper 40s across the Willamette Valley.  The warm
     front had moved into the north valley, by this morning, with
     brisk southerly winds warming the central and southern
     Willamette Valley into the mid 50s.  Steady light rain was
     still falling in the greater Portland area but had tapered
     off south of Aurora.  24-hour Rainfall totals, ending at 4
     am this morning, generally ranged from one-third to
     two-thirds of an inch across the Willamette Valley.

     The Salem sounding this morning showed considerable warming
     aloft since Wednesday, in response to the warm front.  The
     freezing level had jumped from 4500 feet Wednesday morning
     to 9300 feet this morning.  Snow changed to rain overnight
     in the Cascade passes and was tapering off this morning. 
     The ODA surface analysis showed strong southerly pressure
     gradients, in the wake of the warm front, along the
     coast...extending into the Willamette Valley.  South winds
     were gusting to near 40 mph along the northern and central
     coast and locally over 20 mph in the Willlamette Valley.

     The warm front, and associated steady rain, will continue to
     lift northward today and tonight...maintaining the steady
     rainfall across western Washington.  Skies should stay
     mostly cloudy across the Willamette Valley, but continued
     brisk southerly winds will likely lift afternoon
     temperatures into the low 60s.  The warmer surface
     temperatures and southerly winds will make for good
     ventilation conditions today. There is still a chance of a
     little rain at times across western Oregon, but additional
     amounts should be less than one-tenth of an inch. Continued
     mild southerly winds will hold overnight temperatures in the 50s.

Surface Winds:
     S 10-20 this morning, S 10-20 this afternoon.
Transport Winds:
     SSW 22 this morning, SSW 25 this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 2500 feet.  Ventilation index 63.
High Temperature:
     Salem\'s high temperature today will be near 62.
Humidities:
     Minimum relative humidity will be near 67%.
Sunrise/Sunset:
     Salem sunset tonight: 4:53pm; sunrise tomorrow: 6:59am.

Extended Outlook:
     The rain should stay mainly north of Oregon Friday, with
     steady warm-frontal rain continuing across western
     Washington.  Mild southerly winds will likely push afternoon
     temperatures into the low 60s again.  Another Pacific storm
     system is forecast to bring more rain to the region
     Saturday, but snow levels should remain above the Cascades
     passes until the cold front pushes east of the region
     Saturday night.

     A cool upper-level trough will continue to bring showers to
     the region Sunday with the snow level around 4000 feet.  The
     next system will likely bring back steady rain on Monday
     with the snow level lifting to around 5000 feet.  A stronger
     system is forecast to bring more rain Tuesday with the snow
     level rising a touch more.  A warm front will continue the
     rain Wednesday with rising snow levels.  Mild southerly
     winds may move into the valley by Thursday, which could push
     temperatures back into the low 60s.

Tomorrow (07 Nov):  Mostly Cloudy and Mild.  Chance of Light Rain..Mainly North.  52/62

Sat (08 Nov):  Rain Likely...Turning to Showers by Evening.  49/55

Sun (09 Nov):  Showers.  Snow Level 4000 Feet.  42/52

Mon (10 Nov):  Rain Likely.  Snow Level Near 5000 Feet.  40/54

Tue (11 Nov):  Rain Likely.  Snow Level Near 5500 Feet.  43/54

Wed (12 Nov):  Rain Likely.  Snow Level Rising to Near 7000 Feet.  43/55

Thu (13 Nov):  Mostly Cloudy and Mild.  Chance of Light Rain.  49/60

ODA Meteorologist
weather at oda.state.or.us