SMI South Central (Smoke Management Instructions) South Central Oregon Smoke Management Instructions

[ODF Smoke Management Instructions]

SMOKE MANAGEMENT FORECAST AND INSTRUCTIONS
SALEM FORESTRY WEATHER CENTER
OREGON DEPARTMENT OF FORESTRY

ISSUED: Monday, April 20, 2009       2:40 PM      Jim Little

1.  DISCUSSION AND FORECAST FOR SOUTH CENTRAL OREGON ZONES 624 AND 625

The ridge of high pressure in the upper atmosphere that has brought the sunshine and warm weather to the Pacific Northwest will remain on Tuesday; however it will start to weaken as an upper level low pressure area moves across the northern Gulf of Alaska.  Mixing heights should be favorable for good smoke dispersion, reaching to 5000 feet during the afternoons after morning surface inversions break.   Transport winds will be generally southerly in the morning changing to west-southwest in the afternoon.

    OUTLOOK (WEDNESDAY - FRIDAY):

The tail end of the Gulf of Alaska low digs south to off the British Columbia coast on Wednesday, but weather will remain dry.  Isolated afternoon thunderstorms are possible over mountainous areas.  On Thursday the upper trough sweeps into the Pacific Northwest.  Moisture will be very limited but isolated showers are likely throughout the region.  The trough will slowly shift eastward through the region Friday.  Mixing heights should be favorable for good smoke dispersal throughout the outlook period.  Expect generally southwesterly transport winds throughout the area.

2.  DISPERSION

TUESDAY
Mixing height 1100 - 2100 ft during the morning.  Mixing height rises above 5000 ft during the afternoon then lowers below 1000 ft during the evening.

Transport wind light and variable and controlled by local terrain during the morning.  Transport wind increases to WSW to WNW at 9 - 15 mph during the afternoon then shifts and increases to NW to NNW at 12 - 22 mph during the evening.

Surface wind light and variable and controlled by local terrain during the morning.  Surface wind increases to WSW to NW at 6 - 12 mph during the afternoon and evening.

OUTLOOK:

WEDNESDAY
Mixing height below 1000 ft early rising to 3000 - 4000 ft by late morning rising to 4000 - 5000 ft during the afternoon.  Transport wind WNW to NNW at 6 - 10 mph during the morning becoming W to WNW at 16 - 30 mph during the afternoon.  Surface wind light and variable during the morning becoming W to WNW at 12 - 22 mph during the afternoon.

THURSDAY
Mixing height below 1000 ft early rising to 4500 - 5000 ft by late morning and through the afternoon.  Transport wind WSW to NW at 5 - 9 mph during the morning becoming WNW to NW at 10 - 18 mph during the afternoon.  Surface wind W to NW at 5 - 9 mph during the morning becoming WNW to NW at 10 - 18 mph during the afternoon.

FRIDAY
Mixing height 3000 - 4000 ft during the morning rising to 4500 - 5000 ft during the afternoon.  Transport wind WSW to NW at 4 - 8 mph during the morning becoming NW to N at 6 - 12 mph during the afternoon.  Surface wind WSW to NW at 4 - 8 mph during the morning becoming NW to N at 6 - 12 mph during the afternoon.

3.  BURNING INSTRUCTIONS FOR ZONES 624 AND 625 INCLUDING THE WALKER
    RANGE PORTION OF ZONE 624
This instruction is valid for burning conducted on Tuesday, April 21, 2009.
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Avoid ignitions within 15 miles to the SW through NNW of SSRAs.  For units that will smolder significantly through the night avoid burning within at least 35 miles to the SW through NNW in or near drainages leading to SSRAs.  Recommend against burning units that will smolder significantly overnight.

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4.  SPECIAL NOTE:

    The smoke management forecaster is available at (503)
    945-7401.  The smoke management forecaster is available
    to discuss specific burns.  The duty forecaster phone
    number is (503) 945-7401. Please call this number and
    not individual's numbers to discuss daily burning. Please
    avoid calling before 8 a.m. and between 2 to 3 p.m.

    This forecast is available on the Internet at:
      http://oregon.gov/ODF/FIRE/fire.shtml/#Smoke_Management

    Please ensure your units have been planned and accomplished by checking:
      http://oregon.gov/ODF/FIRE/SMP/dailysmoke.shtml


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