[willamette-fcst] Forecast - Tuesday, November 17th, 2009

Tue Nov 17 12:00:20 PST 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: 
     Tuesday, November 17th, 2009 at 12:00pm.

Burn Advisory:
     Agricultural burning is allowed.  Suggested burn times are from now until 2:30pm.
     Straw stack burning is allowed, for dry stacks, from now until 2:30pm.

Weather Discussion:
     A slow-moving cold front produced areas of heavy rain and strong southerly winds across
     western Washington and western Oregon Monday through early this morning.  Southerly winds
     gusted to around 90 mph Monday afternoon and evening at exposed coastal headlands and in
     the higher elevations of the Oregon coast range. The strnogest reported gust was 98 mph,
     in Newport, late Monday evening.  Cape Foul Weather and Waldport both recorded gusts of
     95 mph, and Garibaldi had a gust of 89 mph.  Many locations along the southern washington
     and Oregon coastlines recorded gusts between 50 and 75 mph.

     Southerly winds moved into the Willamette Valley Monday night, with gusts between 40 and
     50 mph.  Similar wind gusts moved into the northern Oregon Cascades early this morning.
     There were reports of downed trees and some wind damage to structures along the coast.
     Some power outages were reported from the coast to the northern Willamette Valley.

     A updated list of peak wind gusts, and damage reports, from various southern
     Washington and Oregon locations, is available from the National Weather Service at:
     http://www.wrh.noaa.gov/images/nwscwi/officenames/wfo_portland.jpg

     Heavy rain began falling late Monday morning, on the northern Oregon Coast and coastal
     range, and continued through early this morning.  Over 4 inches of rain fell in sections
     of the northern Oregon coast range with more than 3 inches recorded in Astoria.  The rain
     spread south and east Monday night, with the central and south coast getting 1-2 inches of
     rain by late this morning.  The rain and strong southerly winds moved into the Willamette
     Valley Monday night, with most of the valley picking up about one-half inch of ran by late
     this morning.  Some northern Cascade foothill locations received 1 1/2 inches of rain.

     The heavy rain and high surf combined to caused some coastal flooding and tidal overflow.
     Flood warnings have been dropped for the Nehalem River, but a coastal flood advisory
     remains in effect until 3 p.m., for minor tidal overflow, along the northern Oregon Coast.
     A high surf advisory remains in effect until 6 p.m. for the northern Oregon Coast.

     The cold front, and strongest winds, were pushing into eastern Oregon late this morning,
     where southerly winds were gusting to around 30 mph.  The front lost a lot of moisture,
     as it crossed over the Cascades, with mainly just a lot a cloudiness  and breezy conditions
     making it into central and eastern Oregon.  Southerly wind gusts were generally in the
     10-20 mph range west of the Cascades, with temperatures ranging from the mid 40s to near 50.

     Satellite imagery showed some clearing, in the immediate wake of the cold front, across
     western Washington and northwestern Oregon, late this morning.  However, a cold upper-level
     trough was evident just off the Washington and northern Oregon coastlines.  As that moves
     onshore later today and tonight, showers will increase across the region with a slight
     chance of thunderstorms.  Valley highs will struggle to hit the low 50s this afternoon.

     Snow levels dropped, in the Cascades, along the back edge of the cold front, with snow
     accumulating over the passes late this morning.  There may be a brief break in the snowfall
     early this afternoon, before the instability showers drop the snow level further late this
     afternoon and tonight.  Significant snow accumulations are likely over the mountain passes
     down to as low at 2500 feet. 

Surface Winds:
     SSW 5-15 G20 this afternoon.
Transport Winds:
     SSW 20 this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 2000 feet.  Ventilation index 44.
High Temperature:
     Salem\'s high temperature today will be near 51.
Humidities:
     Minimum relative humidity will be near 63%.
Sunrise/Sunset:
     Salem sunset tonight: 4:41pm; sunrise tomorrow: 7:14am.

Extended Outlook:
     Showers will continue through most of Wednesday, with
     another wet and quite windy weather system forecast to move
     onshore late Thursday into Friday morning.  Snow levels will
     climb back to near or above the Cascade passes by Thursday
     afternoon, as the cold front nears the coastline.  Rain will
     turn to showers Friday, with the cold front likely pushing
     east of the Cascades by evening.  The snow level will drop
     back to around 2500 feet by Friday night.

     Showers will continue Saturday, with yet another weather
     system forecast to come onshore Saturday night.  That will
     be a colder system, with possibly heavy snow in the
     Cascades.  Showers will likely taper off Sunday afternoon,
     with a warm front now slated to spread more rain across
     western Oregon Monday...along with rising snow levels.  We
     may get a break from the rain next Tuesday, but that is
     getting beyond the range of the computer models with this
     type of weather pattern.

Tomorrow (18 Nov):  Showers.  Snow Level 2500-3000 Feet.  40/49

Thu (19 Nov):  Increasing Rain and Blustery.  Snow Level Rising to 4-5000 Feet.  42/55

Fri (20 Nov):  Rain Turning to Showers.  Snow Level Dropping to 2500 Feet.  41/49

Sat (21 Nov):  Showers.  Snow Level 2500-3000 Feet.  39/48

Sun (22 Nov):  Rain and Mountain Snow...Turning to Showers.  Snow Level near 3000 Feet. 42/49

Mon (23 Nov):  Rain.  Snow Level Rising to 5-6000 Feet.  42/53

Tue (24 Nov):  Partly Sunny.  40/51

ODA Meteorologist
weather at oda.state.or.us