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

[ODF Smoke Management Instructions]

SMOKE MANAGEMENT FORECAST AND INSTRUCTIONS

SALEM FORESTRY WEATHER CENTER

OREGON DEPARTMENT OF FORESTRY



ISSUED: Saturday, November 20, 2010       2:40 PM      Pete Parsons



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



SUNDAY



A cold upper-level trough will remain over the region.  One disturbance will rotate inland, across northern California, with accumulating snow likely across most of the region.  Expect good smoke dispersal conditions with westerly transport winds. Snow may taper off in the afternoon, but another upper-level disturbance is forecast bring a renewed threat of snow to the region by Sunday night, along with even colder air.


OUTLOOK (MONDAY-WEDNESDAY)

On Monday, an even colder upper-level system will drop southward and maintain areas of snow across the region.  This system will be accompanied by a surface Arctic cold front, which will enhance the snowfall Monday night and then usher in the coldest air of the season.  Smoke dispersal conditions should remain good with brisk westerly transport winds.



On Tuesday, a very cold and drier northerly flow is forecast, with sub-freezing temperatures and snow-covered ground likely.  Skies will slowly clear with a chance of light snow showers.  Cold low-level air will stabilize the air mass, with only marginal to fair smoke dispersal conditions and decreasing westerly transport winds.



Computer models show an upper-level ridge building over the region by Wednesday with a dry and much more stable northerly flow aloft.  That will lead to very cold temperatures and surface-based inversions.  There may be areas of morning fog and low clouds.  A weak impulse in the northerly flow may to bring some high clouds to the region in the afternoon.  Smoke dispersal conditions will deteriorate to poor.



2.  DISPERSION



SUNDAY

Mixing height below 1500 ft early rising to 3000 - 4000 ft by late morning.  Afternoon mixing height rises above 5000 ft then lowers to 2700 - 3700 ft during the evening.



Transport wind NW to N at 9 - 15 mph during the morning.  Transport wind shifts to W to NW and increases to 15 - 25 mph during the afternoon then increases to WSW to W at 18 - 30 mph during the evening.



Surface wind NW to N at 8 - 12 mph during the morning.  Surface wind shifts to WSW to WNW at 9 - 15 mph during the afternoon and evening.



OUTLOOK:



MONDAY

Mixing height 4000 - 5000 ft during the morning rising above 5000 ft during the afternoon.  Transport wind W to WNW at 22 - 38 mph.  Surface wind WSW to WNW at 10 - 20 mph.



TUESDAY

Mixing height 2200 - 3200 ft during the morning rising to 3300 - 4300 ft during the afternoon.  Transport wind WNW to NNW at 9 - 15 mph.  Surface wind light and variable.



WEDNESDAY

Mixing height below 1000 ft during the morning rising to 1000 - 2000 ft during the afternoon.  Transport wind light and variable.  Surface wind light and variable.



3.  BURNING INSTRUCTIONS FOR ZONES 624 AND 625 INCLUDING THE WALKER

    RANGE PORTION OF ZONE 624

This instruction is valid for burning conducted on Sunday, November 21, 2010.

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Avoid ignitions within 12 miles to the WSW through N of SSRAs.  Watch for shifting transport winds.  No additional restrictions necessary.



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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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