[willamette-fcst] Forecast - Wednesday, April 7th, 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.

     This daily Willamette Valley Agricultural Weather Forecast will become a seasonal product,
     as of Friday April 16th. The last broadcast and email of this forecast will be Thursday,
     April 15th. It will return as the \"Willamette Valley Field Burning Weather Forecast,\"
     issued daily via email and broadcast on WPOZ 585, beginning Thursday July 1st.

Issued: 
     Wednesday, April 7th, 2010 at 12:00pm.

Burn Advisory:
     Recommended burn times for agricultural burning are from now until 6:00pm.
     Straw stack burning is allowed from now until 5:00pm.

Weather Discussion:
     A Pacific warm front is spreading clouds across most of Washington
     and the northwestern corner of Oregon today.  Some light rain has fallen
     this morning along the northern Oregon coast and the extreme northern
     Willamette Valley.  Astoria picked up .02 inches of rain in the 6-hour
     period ending at 11 a.m.  Portland received a trace of rain.  Doppler radar
     showed another area of light rain advancing onto the northern Oregon coast and
     into the northern coastal range at midday.  The rain appeared to extend about as
     far south as Newport.

     Meanwhile, satellite imagery showed some breaks in the clouds over the southern
     Willamette Valley.  Skies were mostly sunny, at midday, over southwestern, central
     and eastern Oregon.  Temperatures ranged mostly from the upper 40s to mid 50s on
     both sides of the Cascades.  The late-morning ODA surface analysis showed very weak
     southeasterly pressure gradients across western Oregon with winds generally less
     than 10 mph.  

     The warm front is forecast to lift northward this afternoon but will continue to
     bring a chance of sprinkles or light rain to the north coast and the extreme northern
     Willamette Valley. Skies should remain mostly sunny over the south valley, with
     considerable middle and high clouds covering the north valley.

     Freezing levels have jumped well above 6000 feet and are continuing to rise ahead of
     a cold front that is approaching the northern tip of Vancouver Island, British Columbia.
     Warmer air aloft and some filtered sunshine should help temperatures climb into the
     low 60s across the Willamette Valley this afternoon, which is near normal for early
     April.  The north valley will likely stay a little cooler than the south valley.  

Surface Winds:
     SE 3-8...becoming SSW 5-10 by late this afternoon.
Transport Winds:
     S 8...becoming SSW 8 by late this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 3000 feet.  Ventilation index 24.
High Temperature:
     Salem\'s high temperature today will be near 61.
Humidities:
     Minimum relative humidity will be near 48%.
Sunrise/Sunset:
     Salem sunset tonight: 7:48pm; sunrise tomorrow: 6:40am.

Extended Outlook:
     The break in the weather will be brief, with another strong
     cold front forecast to spread more rain onshore shortly
     after midnight.  Rain will likely spread into the Willamette
     Valley during the pre-dawn hours Thursday.  The cold front
     will also bring blustery south winds to both the coast and
     the Willamette Valley Thursday morning.  Snow levels will
     quickly drop in the wake of the cold front Thursday
     afternoon, with significant snow accumulations likely over
     the Cascade passes and in the higher elevations of the coast range.

     An upper-level trough will keep a chance of showers over the
     region Friday...mainly north.  We may get a brief break in
     the action, on Saturday, with the next weather system moving
     into the region Sunday.  Cool and showery conditions will
     likely persist through the first half of next week, with
     continued unseasonably low snow levels.

Tomorrow (08 Apr):  Rain, Windy, & Much Cooler.  Snow Level Dropping to 3000 Feet.  43/49

Fri (09 Apr):  Chance of Showers....Mainly North.  Snow Level 2-3000 Feet.  34/52

Sat (10 Apr):  Partly Cloudy.  Chance of Showers.  Snow Level Rising to 4-5000 Feet.  33/59

Sun (11 Apr):  Increasing Showers.  Cooler.  Snow Level 4000 Feet.  37/56

Mon (12 Apr):  Showers Likely.  Cooler.  Snow Level 3-4000 Feet.  36/53

Tue (13 Apr):  Showers Likely.  Continued Cool.  Snow Level 3000 Feet.  37/53

Wed (14 Apr):  Showers Likely.  Continued Cool.  Snow Level 3000 Feet.  37/53

ODA Meteorologist
weather at oda.state.or.us