[willamette-fcst] Forecast - Friday, February 27th, 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: 
     Friday, February 27th, 2009 at 9:00am.

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

Weather Discussion:
     The cold upper-level low-pressure system that moved across
     Oregon Thursday rapidly pushed east of the region
     overnight...allowing for clearing skies.  Willamette Valley
     temperatures dropped well below freezing overnight, with
     areas of dense fog making for locally slick travel
     conditions this morning.  McMinnville dipped down to just 26
     degrees this morning, and it was only 27 in Hillsboro. 
     Mid-morning temperatures were generally in the low 30s with
     widespread fog and low clouds.

     A transitory ridge of high pressure will likely allow for at
     least partly sunny skies later today, but temperatures will
     be well below normal.  Valley highs will only raech the mid
     to upper 40s.  Normal valley highs, for late February, would
     be the low to mid 50s.  The ODA surface analysis showed weak
     offshore pressure gradients.  Light north-northeasterly
     winds in the valley this morning may become light
     southeasterly this afternoon.  The freezing level over Salem
     was just 1100 feet this morning and will slowly rise to
     about 3000 feet this afternoon.

Surface Winds:
     NE 0-5 this morning, ESE 5 this afternoon.
Transport Winds:
     ESE 5 this morning, S 5 this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 3000 feet.  Ventilation index 15.
High Temperature:
     Salem\'s high temperature today will be near 48.
Humidities:
     Minimum relative humidity will be near 60%.
Sunrise/Sunset:
     Salem sunset tonight: 5:57pm; sunrise tomorrow: 6:51am.

Extended Outlook:
     Mostly clear skies this evening will lead to areas of fog
     forming overnight.  Valley temperatures should, once again,
     drop to near or below freezing by Saturday morning. The next
     weather system will increase clouds over the region Saturday
     with a chance of rain by the afternoon.  Increasing
     southwesterly flow aloft should lift the snow level to near
     or slighty above the Cascade passes.  Rain is likely
     Saturday night and Sunday, as the storm moves onshore.  Snow
     levels will hover around the Cascade passes Sunday, before
     dropping to near 3000 feet Sunday night.

     An upper-level trough will slowly move onshore Monday and
     Tuesday with an ongoing threat of showers.  Snow levels
     should stay in the 3-4000 foot range.  Valley temperature
     will be near normal. A stronger and colder system is
     forecast to bring more rain and mountain snow late Wednesday
     and Thursday with showers continuing into Friday.

Sat (28 Feb):  Increasing Clouds.  Chance of PM Rain.  Snow Level Rising to 4000 Feet.  31/49

Sun (01 Mar):  Rain.  Snow Level 4000 Feet...Dropping to 3000 Feet Late.  39/52

Mon (02 Mar):  Showers.  Snow Level  3-4000 Feet.  37/51

Tue (03 Mar):  Mostly Cloudy.  Chance of Showers.  Snow Level near 4000 Feet.  37/52

Wed (04 Mar):  Rain Increasing.  Snow Level 3-4000 Feet.  36/51

Thu (05 Mar):  Rain Turning to Showers.  Snow Level Dropping to 2000 feet.  35/49

Fri (06 Mar):  Showers.  Mountain Snow.  Snow Level Near 2000 Feet.  35/40

ODA Meteorologist
weather at oda.state.or.us