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: Friday, October 8, 2010       2:40 PM      Pete Parsons



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



SATURDAY



The jet stream is transitioning to a more autumn-like pattern.  On Friday, a developing westerly flow aloft helped to kick east of the region the upper-level low pressure system that has been bringing showers to mainly eastern districts.  It also pushed a very weak cold front across northern Oregon.



A stronger system, with some entrained tropical moisture, will approach the coastline early Saturday.  The bulk of the rainfall from this system is forecast to stay north and west of the region.  The cold front is forecast to stall and push north, as a warm front, Saturday afternoon and evening. Southwesterly transport winds will continue to improve ventilation conditions, but warming aloft and cloud-cover will keep afternoon mixing heights somewhat suppressed.  Smoke dispersal conditions will be fair.


OUTLOOK (SUNDAY-TUESDAY)


The chance of rain will increase, from west to east, across south-central Oregon on Sunday, as a strong cold front sweeps across the state.  Increasing southwesterly transport winds will greatly improve ventilation conditions.  Winds will veer to westerly, in the wake of the cold front, Sunday evening.  There will not be much post-frontal shower activity, because the air aloft will stay fairly mild.



The flow aloft is forecast to dry out and turn northwesterly on Monday.  There will likely still be enough mixing and instability for a few mountain showers Monday morning.  Transport winds will turn northerly, and begin to weaken.  Even with some afternoon sunshine, mixing heights will be suppressed by subsidence aloft, associated with the building ridge of high pressure.  Smoke dispersal conditions will be only fair.



As the upper-level ridge continues to build over the region, strong surface-based inversions are likely by Tuesday morning.  Patchy morning valley fog is possible.  Mostly sunny skies are expected by the afternoon, but low mixing heights and light transport winds will likely make for marginal to poor ventilation conditions.



2.  DISPERSION



SATURDAY

Mixing height below 1000 ft early rising to 2000 - 3000 ft by late morning.  Afternoon mixing height rises to 3500 - 4500 ft then lowers below 1000 ft during the evening.



Transport wind SSW to WSW at 9 - 15 mph during the morning.  Transport wind decreases to SW to W at 6 - 10 mph during the afternoon and evening.



Surface wind SSE to SW at 4 - 8 mph during the morning.  Surface wind becomes light and variable and controlled by local terrain during the afternoon and evening.



OUTLOOK:



SUNDAY

Mixing height below 1000 ft early rising to 2500 - 3500 ft by late morning rising above 5000 ft during the afternoon.  Transport wind light and variable during the morning becoming WSW to WNW at 8 - 12 mph during the afternoon.  Surface wind light and variable during the morning becoming WSW to NW at 5 - 9 mph during the afternoon.



MONDAY

Mixing height 1400 - 2400 ft during the morning rising to 2700 - 3700 ft during the afternoon.  Transport wind N to NE at 6 - 10 mph.  Surface wind light and variable during the morning becoming NNW to NE at 4 - 8 mph during the afternoon.



TUESDAY

Mixing height below 1000 ft early rising to 1000 - 2000 ft by late morning rising to 2500 - 3500 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 Saturday, October 9, 2010.

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Avoid ignitions within 15 miles to the SSW through NW of SSRAs.  For units that will smolder significantly through the night avoid burning within at least 30 miles to the SSW through NW in or near drainages leading to SSRAs.  Recommend against burning units that will smolder significantly overnight.  Complete ignitions by 4 p.m.



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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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