[willamette-fcst] Forecast - Monday, July 16th, 2007

[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, July 16th, 2007 at 9:00am.

Burn Advisory:
     Agricultural burning is allowed.  Suggested burn times are from 12:00pm until 6:00pm.
     Preparatory burning is allowed from 12:00pm until 2:00pm with a 100 acre limit.
     Propane flaming is allowed from 12:00pm until 6:00pm.
     Straw stack burning is allowed from 12:00pm until 6:00pm.

Weather Discussion:
     The upper-level ridge of high pressure, that was over the
     Pacific Northwest last week, has moved eastward to over the
     Rockies.  An upper-level low pressure area is over the
     Eastern Pacific Ocean this morning, with a southwesterly
     flow aloft over Washington and Oregon. Middle and high
     clouds cover most of Western Washington and NW Oregon this
     morning.  Onshore flow has also spread some marine
     low-clouds into the Willamette Valley.  The low clouds
     should break up this afternoon, but the middle and high
     clouds will be more persistent.

     With a high mixing layer and onshore flow today, there is
     some potential for burning this afternoon.  However, as the
     approaching upper-level low pressure area draws nearer to
     the coastline, the transport winds may become more southerly,
     which is not conducing to burning. We will start pibol readings,
     from Salem, at noon to monitor the transport winds.

Surface Winds:
     W 6 this morning, WNW 8 this afternoon.
Transport Winds:
     NW 7 this morning, SW 9 this afternoon.
Atmospheric Ventilation Conditions:
     Maximum mixing height today will be near 5500 feet.  Ventilation index 50.
High Temperature:
     Salem\'s high temperature today will be near 82.
Humidities:
     Relative humidity drops to 50% by 3pm.
     Minimum relative humidity will be near 37%.
Sunrise/Sunset:
     Salem sunset tonight: 8:55pm; sunrise tomorrow: 5:42am.

Extended Outlook:
     A fairly strong and moist upper-level low pressure area will
     approach the coastline Tuesday and Wednesday, with an
     increasing chance of showers and southerly winds aloft over
     Western Oregon.  This system is forecast to move onshore
     late Wednesday and Thursday, with cool and showery weather
     west of the Cascades and a good chance for thundershowers in
     Central and Eastern Oregon.

     A drier southwesterly flow aloft takes over, starting
     Friday, as the Pacific Northwest, once again, becomes
     sandwiched between high pressure over the Rockies and low
     pressure in the Eastern Pacific.  The long-range computer
     models go different directions starting this weekend, so
     confidence in the forecast beyond Sunday is low.

Tomorrow (17 Jul):  Mostly Cloudy.  Increasing Chance of Showers. 59/77

Wed (18 Jul):  Showers Likely.  58/77

Thu (19 Jul):  Showers Likely.  56/73

Fri (20 Jul):  Morning Clouds...Partly Cloudy Afternoon.  55/83

Sat (21 Jul):  Partly Cloudy and Warm.  56/86

Sun (22 Jul):  Mostly Sunny and Warm.  56/87

Mon (23 Jul):  Increasing Clouds.  56/85

ODA Meteorologist
weather at oda.state.or.us