[willamette-fcst] Forecast - Friday, October 23rd, 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.

        The October Update of the ODA Seasonal Climate Forecast is Available at:
              http://oregon.gov/ODA/NRD/weather.shtml#Weather_forecasts

        ...Next Update Not Until Wednesday, October 28th, 2009 at 9:00am...

Issued: 
     Friday, October 23rd, 2009 at 9:00am.

Burn Advisory:
     Agricultural burning is allowed.  Suggested burn times are from 10:00am until 4:30pm.
     Straw stack burning is allowed, for dry stacks, from 10:00am until 4:30pm.

Weather Discussion:
     Satellite imagery showed an impressive cloud-shield,
     associated with a Pacific frontal system, covering all of
     Washington and most of Oregon.  The main low-pressure center
     was moving across the northern tip of Vancouver Island,
     British Columbia, with a cold front extending southwestward
     to about 200 miles off the Oregon Coast.  Doppler radar and
     surface reports showed areas of locally heavy rain, west of
     the Cascades, from western Washington southward to Eugene, Oregon.

     As of 8 a.m., the northern Oregon Coast had already received
     close to one-third of an inch of rain, with around one-tenth
     of an inch falling across the Willamette Valley.  Light rain was
     also spreading across all of central and eastern Washington and
     much of north-central Oregon.  Rain will continue to spread south
     and east, across Oregon, this morning...possibly extending clear
     to the southeastern corner of the state by later this afternoon.

     Southerly pressure-gradients are also increasing across
     northwestern Oregon, with winds gusting to around 30 mph on
     the north coast.  South winds will become gusting in the
     Willamette Valley, as well, today.  Mid-morning temperatures
     were mostly in the mild low to mid 50s across western Oregon,
     but highs this afternoon will only climb to around 60 degrees.

     Rainfall amounts could approach an inch along the north
     coast today and exceed one-third of an inch in the Willamette
     Valley.  Rainfall totals will taper off to the south and
     east, but even the southwestern valleys, and the northern
     half of central and eastern Oregon, could pick up over
     one-tenth of an inch.  The rain should taper off to showers,
     across western Oregon, by this evening, with partial clearing
     leading to areas of fog formation by Saturday morning.

Surface Winds:
     S 10-20 G25 this morning, WSW 10-20 G25 this afternoon.
Transport Winds:
     S 25 this morning, SW 25 this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 3500 feet.  Ventilation index 88.
High Temperature:
     Salem\'s high temperature today will be near 61.
Humidities:
     Minimum relative humidity will be near 78%.
Sunrise/Sunset:
     Salem sunset tonight: 6:13pm; sunrise tomorrow: 7:40am.

Extended Outlook:
     A transitory ridge of high pressure will dry things out
     Saturday.  Widespread morning fog is likely, with some
     clearing in the afternoon.  Clouds will increase Sunday
     morning, in association with a warm front that will likely
     bring some rain to northwestern Oregon Sunday afternoon. 
     The jet stream is forecast to strengthen, and take aim more
     at Washington and Oregon by Sunday night.  A strong cold
     front will bring more significant rain to western Oregon by
     early Monday, following by a cold upper-level trough Monday
     afternoon and night. Colder air aloft will drop the snow
     level down to the northern Cascade passes by Monday night.

     Strong northwesterly flow aloft will maintain scattered
     showers across western Oregon Tuesday, with the snow level
     remaining at or below the Cascade passes.  As the
     upper-level trough exits to the east, on Wednesday, the flow
     aloft will turn more northerly and dry out.  A fairly strong
     ridge is now forecast to build over the west coast, during
     the middle of next week, bringing dry and stagnant
     conditions, with below normal temperatures.  Overnight
     minimums will likely drop well down into the 30s, across the
     Willamette Valley, with possible areas of frost. 
     Temperatures will moderate, close to normal, by the end of
     the week.

Tomorrow (24 Oct):  AM Fog and Low Clouds.  Partial Afternoon Clearing.  43/62

Sun (25 Oct):  AM Fog.  Increasing Clouds.  Light Rain Developing...Mainly North.  40/58

Mon (26 Oct):  Rain Turning to Showers.  Snow Level Dropping to 3-4000 Feet Late.  50/58

Tue (27 Oct):  Scattered Showers and Cool.  Snow level 3-4000 Feet.  42/55

Wed (28 Oct):  Areas of AM Fog. Partly Sunny and Cool. Freezing Level near 5000 Feet.  35/56

Thu (29 Oct):  Areas of AM Fog.  Possible Frost.  Afternoon Clearing.  34/57

Fri (30 Oct):  Areas of AM Fog.  Partly Sunny.  37/60

ODA Meteorologist
weather at oda.state.or.us