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, April 30, 2011       2:40 PM      Pete Parsons



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


SUNDAY

A drying northwesterly flow aloft will help to clear skies, in the wake of an unseasonably cold upper-level trough.  After another record-cold morning, a transitory upper-level ridge is forecast to move onshore and warm the air mass.  High temperatures should rebound close to normal, with the freezing level jumping above 8000 feet.   Afternoon heating will likely provide good mixing, with transport winds slackening and turning mostly south to southeasterly.

OUTLOOK (MONDAY-WEDNESDAY)
The upper-level ridge will push east of the state Monday with an increasing westerly flow aloft directing a cold front onshore by the afternoon.  Clouds will increase, but most of the shower activity appears as if it will stay just north of the region.  Surface temperatures will warm to near normal, as the freezing level drops to around 6000 feet.  Mixing will be good, with increasing southwesterly transport winds turning more westerly in the afternoon.

A weak upper-level trough will push east of the state Tuesday, with a return to a dry northwesterly flow aloft.  Skies should be partly cloudy.  The freezing level will rise above 9000 feet, but cool northwest to north winds will hold surface temperatures near normal.  The combination of warming aloft and cool surface temperatures will suppress mixing heights slightly, with fair to good afternoon mixing.

Another weak and transitory upper-level ridge is forecast to move onshore by Wednesday afternoon, bringing sunny and warmer conditions.  The freezing level will lift to over 10,000 feet.  High temperatures will recover to above normal, which should provide good afternoon mixing.  Transport winds will be light north to northeasterly.

The upper-air pattern is forecast to remain progressive, with long-range computer models differing on the strength of a weaker weather system forecast to come onshore late Thursday and Friday. A more significant cool-down, with a good chance of rain and snow, is advertised by all of the computer models for late next weekend.



2.  DISPERSION



SUNDAY

Mixing height below 500 ft early rising to 3000 - 4000 ft by late morning.  Afternoon mixing height rises above 5000 ft then lowers to 1500 - 2500 ft during the evening.



Transport wind ESE to S at 5 - 9 mph.



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



OUTLOOK:



MONDAY

Mixing height below 1000 ft early rising to 3500 - 4500 ft by late morning rising above 5000 ft during the afternoon.  Transport wind SSW to SW at 15 - 25 mph during the morning becoming WSW to WNW at 15 - 29 mph during the afternoon.  Surface wind S to SW at 9 - 15 mph during the morning becoming WSW to WNW at 10 - 22 mph during the afternoon.



TUESDAY

Mixing height below 1000 ft early rising to 3000 - 4000 ft by late morning rising to 4000 - 5000 ft during the afternoon.  Transport wind NNW to NNE at 9 - 15 mph.  Surface wind NNW to NNE at 4 - 8 mph.



WEDNESDAY

Mixing height below 1000 ft early rising to 2500 - 3500 ft by late morning rising to 4500 - 5000 ft during the afternoon.  Transport wind ENE to ESE at 5 - 9 mph.  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, May 1, 2011.

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Avoid ignitions within 15 miles to the ESE through SW of SSRAs.  For units that will smolder significantly through the night avoid burning within at least 30 miles to the ESE through SW in or near drainages leading to SSRAs.  Verify transport winds away from SSRAs if burning in any other direction.  Recommend against burning units that will smolder significantly overnight.  Complete ignitions by 6 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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