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

Tue Nov 17 09:00:37 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 9:00am.

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 strong cold front stalled just off the Washington and
     northern Oregon coastlines Monday, as low-pressure areas
     formed along the front and moved into the northern tip of
     Vancouver Island, British Columbia.  That produced strong
     southerly pressure-gradients, ahead of the associated cold
     front, across western Washington and western Oregon for
     about 24 hours, until the cold front finally pushed inland
     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. Waldport recorded a
     gust of 95 mph at 11:09 p.m. Monday and Garibaldi had a gust
     of 89 mph at 4 p.m. Monday.  Many locations along the
     southern washington and Oregon coastlone recorded gusts
     between 50 and 75 mph.  southerly winds also picked up in
     the Willamette Valley Monday evening, with gusts to around
     45 mph.

     A comprehensive list of peak wind gusts at various coastal
     and valley locations is available from the National Weather
     Service at:
     http://www.wrh.noaa.gov/total_forecast/getprod.php?wfo=pqr&pil=PNS&sid=PQR&version=0

     Heavy rain began falling late Monday morning, on the
     northern Oregon Coast and coastal range, and continued
     throughout the day.  Over 4 inches of rain locally fell in
     the northern Oregon coast range with more than 3 inches
     falling in Astoria.  Rainfall amounts tapered off to the
     south and east, but Tillamook received just over 1 1/2
     inches and Newport just under one inch. About three-quarters
     of an inch feel in North Bend and about one-quater of an
     inch in Brookings.  Rainfall increased Monday night in the
     Willamette Valley with most areas picking up between
     one-third and one-half inch by early this morning.  Some
     locations in the northern Cascade foothills received more
     than an inch of rain overnight.

     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 was pushing across central Oregon at
     mid-morning, with the steady rain tapering off and winds
     relaxing across western Oregon.  Southerly wind gusts were
     generally around 20 mph or less west of the Cascades, with
     gusts to near 40 mph across central and eastern Oregon.  A
     cold upper-level trough will move onshore today, bring
     frequent showers, a slight chance of thunderstorms, and
     rapidly lowering snow levels.  ODOT road cameras showed that
     the rain over the passes had turned to snow, by mid-morning,
     and was beginning to accumulate.  Expect winter driving
     conditions over the mountain passes today and tonight, with
     the snow level dropping to near 2500 feet.  Most valley
     locations were in the mid 40s this morning and will struggle
     to reach 50 degrees this afternoon.

Surface Winds:
     SSW 7-15 G22 this morning, SSW 5-15 G20 this afternoon.
Transport Winds:
     SSW 22 this morning, 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