[willamette-fcst] Forecast - Monday, March 2nd, 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: 
     Monday, March 2nd, 2009 at 9:00am.

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

Weather Discussion:
     A slow moving cold front brought about more than an inch of
     rain to sections of the southern and central oregon caoast
     overnight and from one-quarter to three-quarters of an inch
     of rain to the Willamette Valley.  The greatest rainfall
     amounts were in Lane County.  North Bend has picked up just
     over two inches of rain in the past 24 hrs, with the
     southern Willamette valley generally erceiving between
     one-half and three-quarters of an inch.  Some spots in the
     extreme north valley, like the Portland Airport, pickes up
     less than one-quarter of an inch.

     The ODA surface analysis showed the weakening cold front
     along the Cascades at mid-morning.  Southerly flow aloft was
     keeping freezing levels near 6000 feet, with pass
     temperatures in the mid 30s.  Timberline Lodge reported 3
     inches of new snow overnight, so this front was not a big
     snow-maker for the mountains.  ODOT raod cameras showed
     generally wet pavement over the passes.  Pressure were
     relaxing across western Oregon, with south-southeasterly
     winds in the 5-15 mph rain from the coast across the
     Willamette Valley.

     Satellite imagery showed considerable breaks in the clouds
     across western Oregon, in the wake of the cold front.  Some
     sunbreaks will enhance daytime heating, with valley highs
     likely climbing into the mid 50s (a little above normal). 
     With the air aloft slowly cooling today, the afternoon
     heating should help to trigger some instability showers. 
     Ventilation conditions will be good today, with southerly
     transport winds and high mixing heights.

Surface Winds:
     SSE 5-15 this morning, SSE 5-15 this afternoon.
Transport Winds:
     S 20 this morning, S 20 this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 5000 feet.  Ventilation index 100.
High Temperature:
     Salem\'s high temperature today will be near 54.
Humidities:
     Minimum relative humidity will be near 64%.
Sunrise/Sunset:
     Salem sunset tonight: 6:01pm; sunrise tomorrow: 6:46am.

Extended Outlook:
     Another organized system, in the southwesterly flow aloft,
     is forecast to come onshore overnight, which will increase
     the rainfall across western Oregon.  Snow levels will slowly
     drop to below the the cascades passes tonight, with 3-6
     inches of new snow likely by Tuesday morning.  As an
     upper-level trough Showers will continue Tuesday and taper
     off Wednesday, as an upper-level trough weakens and moves onshore.

     a quite cold system is forecast to drop into the region from
     southern British Columbia Thursday with more rain and very
     low snow levels.  This system will need to be watched
     closely for the potential to produce sticking snow in the
     coast range and wet snow down the Willamette Valley floor. 
     Showers will continue Friday with snow levels slowly lifting
     in the afternoon.  The showers may briefly taper off
     Saturday, before another very cold system drops into the
     region Sunday.

Tomorrow (03 Mar):  Rain Turning to Showers.  Snow Level 3500 Feet.  41/53

Wed (04 Mar):  Showers...Decreasing Late.  35/50

Thu (05 Mar):  Rain and Colder.  Snow Level Dropping to 1000 Feet or Less.  34/46

Fri (06 Mar):  showers.  Snow Level Starting Below 1000 Feet and Slowly Rising.  32/47

Sat (07 Mar):  Partly Cloudy.  Slight Chance of Showers.  31/50

Sun (08 Mar):  Increasing Rain and Snow.  Snow Level Possibly Dropping to 500 Feet.  34/46

Mon (09 Mar):  Becoming Partly Sunny.  29/49

ODA Meteorologist
weather at oda.state.or.us