[willamette-fcst] Forecast - Wednesday, January 30th, 2008

[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: 
     Wednesday, January 30th, 2008 at 9:00am.

Burn Advisory:
     Agricultural burning is allowed.  Suggested burn times are from 10:00am until 3:30pm.
     Straw stack burning is allowed from 10:00am until 3:30pm.

Weather Discussion:
     A cold upper-level trough brought locally heavy rain and
     snow showers to Western Oregon overnight and early this
     morning.  Most of the sticking snow fell in the hills.  2-3
     inches of snow fell in the west hills of Portland, above 500
     feet, which was the greatest snowfall there this winter. 
     The Cascades picked up about a foot of new snow overnight. 
     The foothills above 1000 feet, east of Salem, picked up 4+
     inches of new snow, and the coast range received a couple
     more inches.  Wet snow was able to briefly accumulate, under
     heavy showers, down to the valley floors.  Corvallis and
     Salem both received a coating of wet snow.

     The showers and brisk southerly winds helped keep valley
     floor temperatures near to slightly above freezing
     overnight.  By mid-morning temperatures had warmed into the
     mid 30s.   Satellite and radar imagery both show some
     showers still rotating onshore into NW Oregon this morning. 
     The freezing level was measured over Salem early this
     morning at 2000 feet, so the snow levels have likely risen
     to between 500 and 1000 feet over Northwest Oregon, but snow
     could still mix to the valley floors under the heavier
     showers.

     The upper-level trough will quickly shift east of the region
     with showers decreasing later this morning.  High
     temperatures will climb into the low 40s across the valley. 
     Clouds from the next weather system are already moving
     onshore.
   
     Steady rain will return to the coastline later this afternoon
     and move into the valley this evening.  Warmer air aloft will
     lift snow levels to about 2500 feet tonight with more heavy snow
     expected in the Cascades. Strong southerly winds may also hit the
     coastline tonight, where high wind watches are in effect for gusts
     to 65 mph. Ventilation conditions will be good for burning today.

Surface Winds:
     S 10-20 this morning, S 10-20 this afternoon.
Transport Winds:
     SW 20 this morning, SW 25 this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 3000 feet.  Ventilation index 75.
High Temperature:
     Salem\'s high temperature today will be near 42.
Humidities:
     Minimum relative humidity will be near 85%.
Sunrise/Sunset:
     Salem sunset tonight: 5:17pm; sunrise tomorrow: 7:33am.

Extended Outlook:
     The cool stormy pattern is forecast to continue through the
     week with low snow levels at times and heavy snow expected
     in the mountains.  A cool trough will follow tonight\'s storm
     with showers and low snow levels Thursday and Friday.
   
     The next system is forecast to take a more southern track with
     the low-pressure center taking aim at northern Oregon.  That
     track will keep snow levels near or below 1000 feet across
     Western Oregon Saturday.  This storm will need to be monitored
     closely for the possibility of snow levels dropping to the valley
     floors, if it takes a more southern track.  In any case, more
     showers are on tap for Sunday with continued very low snow levels.

     It appears that a transitory ridge will bring some drying on
     Monday with the next weather system bringing more rain and
     mountain snow by Tuesday afternoon.  Another weak ridge will
     bring some drying Wednesday.

Thu (31 Jan):  Rain and Wind...Turning To Showers. Snow Level Dropping to 1000 Feet.  37/43

Fri (01 Feb):  Showers.  Snow Level 1000 Feet.  34/42

Sat (02 Feb):  Rain Turning to Showers.  Snow Level Near or Below 1000 Feet.  33/42

Sun (03 Feb):  Showers.  Snow Level Near 1000 Feet.  33/42

Mon (04 Feb):  Partly Cloudy.  31/43

Tue (05 Feb):  Rain and Windy.  Mountain Snow.  34/46

Wed (06 Feb):  Decreasing Showers.  34/46

ODA Meteorologist
weather at oda.state.or.us