[willamette-fcst] Forecast - Tuesday, June 9th, 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: 
     Tuesday, June 9th, 2009 at 9:00am.

Burn Advisory:
     Agricultural burning is allowed.  Suggested burn times are from 1:00pm until 7:00pm.
     Straw stack burning is allowed from 1:00pm until 7:00pm.

Weather Discussion:
     The weather pattern is transitioning from a cool and stable
     northwesterly flow aloft to a slightly warmer and more
     unstable southwesterly flow aloft this morning.  A weak
     upper-level trough was approaching the coastline, with
     satellite and surface reports showing middle and high clouds
     spreading across most of Oregon.  The early morning sounding
     over Salem showed the upper-level winds had become
     southwesterly with the temperature profile becoming slightly
     more unstable than on Monday.

     The mid-morning ODA surface analysis showed a trough
     extending from southwestern Oregon to north-central and
     northwestern Oregon.  Weak onshore flow brought marine
     clouds into the coastline and the central and southern
     Willamette Valley overnight, but the extreme north valley
     was mostly sunny at mid-morning.  Skies were also starting
     to clear along the north coast.  Mainly just middle and high
     clouds extended east of the Cascades.

     Mid-morning temperatures were mostly in the 50s across
     western Oregon with 50s and low 60s east of the Cascades. 
     With the approaching upper-level trough continuing to back
     the upper-level winds today, from southwesterly to more
     southeasterly, daytime heating will likely help to make the
     atmosphere unstable enough for scattered shower and
     thundershower development...mainly over the Cascades and
     central Oregon.  It is possible that some showers and/or
     t-storms could also develop or move over the western
     valleys. Temperatures will warm into the low to mid 70s this
     afternoon across the Willamette Valley with continued weak
     onshore flow.

Surface Winds:
     S 3-6 this morning, SW 5-10 this afternoon.
Transport Winds:
     Var 3 this morning, WSW 8 this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 4500 feet.  Ventilation index 36.
High Temperature:
     Salem\'s high temperature today will be near 75.
Humidities:
     Minimum relative humidity will be near 45%.
Sunrise/Sunset:
     Salem sunset tonight: 8:57pm; sunrise tomorrow: 5:26am.

Extended Outlook:
     Another weak upper-level trough will continue the threat of
     afternoon showers or t-storms Wednesday...mainly from the
     Cascades eastward.  A more westerly flow aloft may shift the
     instability east of the Willamette Valley Thursday. 
     However, the flow aloft is forecast to become southerly
     again by Friday, with an increasing chance of mainly
     afternoon and evening showers and t-storms across the entire
     state.  Temperatures will likely stay near-normal through the week.

Tomorrow (10 Jun):  Mostly Cloudy.  Slight Chance of PM Showers or T-Storms.  53/71

Thu (11 Jun):  Morning Clouds.  Afternoon Clearing.  51/74

Fri (12 Jun):  Mostly Cloudy.  Chance of PM Showers or T-Storms...Mainly South.  54/73

Sat (13 Jun):  Mostly Cloudy.  Chance of Showers.  Slight Chance T-Storm.  52/72

Sun (14 Jun):  Mostly Cloudy.  Chance of Showers.  51/72

Mon (15 Jun):  Mostly Cloudy.  Slight Chance of Showers.  51/72

Tue (16 Jun):  Morning Clouds.  Becoming Partly Sunny.  50/74

ODA Meteorologist
weather at oda.state.or.us