[willamette-fcst] Forecast - Thursday, April 16th, 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: 
     Thursday, April 16th, 2009 at 9:00am.

Burn Advisory:
     Agricultural burning is allowed.  Suggested burn times are from 11:00am until 6:00pm.
     Straw stack burning is allowed from 11:00am until 6:00pm.

Weather Discussion:
     Clearing skies and calm winds overnight allowed temperatures
     to, once again, drop into the low to mid 30s across most of
     western Oregon.  Some spots in the Willamette Valley dipped
     to or below the freezing mark.  McMinnville had a low of 31
     degrees early this morning.  Hillsboro, Corvallis, and
     Eugene fell to 32 degrees, and Salem hit 34.

     Skies also cleared east of the Cascades, where most areas
     fell below freezing.  Cold temperatures strethced from a
     chilly 21 degrees in Meacham (northeast Oregon) to 19
     degrees at Klamath Falls (south-central Oregon).  The
     mid-morning ODA surface analysis showed weak southerly
     gradients across western Oregon but continued strong onshore
     gradients near the Idaho border.  There was still enough
     westerly wind across eastern and southeastern Oregon
     overnight to keep that area a little warmer.  Baker City
     barely dropped below freezing, with a minimum of 31 degrees.
     Burns did manage to drop down to 23.  West winds were still
     gusting to nearly 30 mph in Ontario at mid-morning, near the
     Idaho border, keeping the temperatures there in the 40s
     overnight.

     Satellite imagery showed clouds from the next weather system
     already moving onto the coastline at mid-morning, with high
     clouds extending east to the Cascades.  A cold front, about
     250 miles offshore, will slowly move east today with clouds
     increasing across the state.  Doppler radar was already
     showing some weak echoes just off the northern Oregon Coast,
     so some sprinkles are possible along the coast today.  It
     should stay dry inland through this afternoon, with
     increasing southerly winds and warmer air aloft (the
     freezing level over Salem was 6200 feet this morning)
     helping temperatures recover to near normal.

     Light rain will likely move onto the coast by this evening
     and spread inland overnight.  The bulk of the moisture from
     this system is forecast to remain north of Oregon, with a
     weaker portion of the cold front dragging across western
     Oregon Friday morning.  Rainfall amounts are forecast to be
     from one-tenth to one-quarter of an inch in the extreme
     north valley and taper off to less than one-tenth of an inch
     over the extreme south valley.

Surface Winds:
     S 3-6 this morning, S 5-10 this afternoon.
Transport Winds:
     SE 6 this morning, S 10 this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 4200 feet.  Ventilation index 42.
High Temperature:
     Salem\'s high temperature today will be near 62.
Humidities:
     Minimum relative humidity will be near 39%.
Sunrise/Sunset:
     Salem sunset tonight: 7:59pm; sunrise tomorrow: 6:24am.

Extended Outlook:
     An upper-level ridge is forecast to build over the Pacific
     Northwest this weekend for dry and warmer conditions through
     the first half of next week.  Cooler and damp conditions may
     return for the second half of next week, with a fairly
     strong upper-level trough forecast to drop into the regin
     from the Gulf of Alaska.

Tomorrow (17 Apr):  Mostly Cloudy.  Light Rain at Times...Mainly North.  44/60

Sat (18 Apr):  Becoming Mostly Sunny and Warmer.  38/70

Sun (19 Apr):  Mostly Sunny and Warmer.  44/75

Mon (20 Apr):  Sunny and Warm.  45/78

Tue (21 Apr):  Increasing Clouds and Cooler.  45/68

Wed (22 Apr):  Chance of Rain and Cool.  44/57

Thu (23 Apr):  Showers and Cool.  40/55

ODA Meteorologist
weather at oda.state.or.us