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: Thursday, April 28, 2011       2:40 PM      Pete Parsons



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


FRIDAY

The axis of an unseasonably cold upper-level trough is forecast to slowly push east of the state with a continued cool and somewhat unstable northwesterly flow aloft. Scattered snow showers are likely, mainly over higher terrain, with well below normal temperatures and snow levels near the valley floors.  Look for good mixing and brisk northwest transport winds.

OUTLOOK (SATURDAY-MONDAY)
An upper-level ridge is forecast to build offshore Saturday with a drier and more stable northwesterly flow aloft over Oregon.  Look for partly cloudy skies.  The snow level will only lift to about 5000 feet, with the air aloft will remaining cold enough for daytime heating to possibly trigger a mountain shower. After a chilly morning, afternoon temperatures will moderate slightly but remain below normal.  Mixing should be good with transport winds veering from northwesterly to mostly northerly.

A weak upper-level ridge axis is forecast to move onshore Sunday, with sunny skies expected.  After a near-record-cold morning, high temperatures should rebound close to normal.  The freezing level will jump to around 9000 feet.   Warming aloft will stabilize the air mass with fair to good afternoon mixing and generally southeasterly transport winds.


The transitory upper-level ridge will push east of the state Monday with an increasing westerly flow aloft bringing a weak cold front onshore by the afternoon.  A lack of cold air aloft, with this system, will only drop the freezing level to around 7000 feet.  Ahead of the cold front, surface temperatures should warm to slightly above normal with good mixing and increasing southwest to westerly transport winds.  The cold front is forecast to only increase clouds across the region, with shower activity staying to the north.



2.  DISPERSION



FRIDAY

Mixing height below 3000 ft early rising to 4000 - 5000 ft by late morning.  Afternoon mixing height rises above 5000 ft then lowers to 2500 - 3500 ft during the evening.



Transport wind WNW to NW at 12 - 22 mph during the morning.  Transport wind increases to NW to NNW at 18 - 30 mph during the afternoon then decreases to NNW to N at 13 - 25 mph during the evening.



Surface wind WNW to NNW at 9 - 15 mph.



OUTLOOK:



SATURDAY

Mixing height 2100 - 3100 ft during the morning rising above 5000 ft during the afternoon.  Transport wind NW to N at 4 - 8 mph.  Surface wind light and variable during the morning becoming NW to NNW at 8 - 12 mph during the afternoon.



SUNDAY

Mixing height below 1000 ft early rising to 2500 - 3500 ft by late morning rising to 4000 - 5000 ft during the afternoon.  Transport wind E to SE at 4 - 8 mph during the morning becoming SE to S at 4 - 8 mph during the afternoon.  Surface wind light and variable.



MONDAY

Mixing height below 1000 ft early rising to 2500 - 3500 ft by late morning rising to 4500 - 5000 ft during the afternoon.  Transport wind SSW to SW at 12 - 24 mph during the morning becoming WSW to W at 15 - 25 mph during the afternoon.  Surface wind S to SW at 8 - 12 mph during the morning becoming WSW to WNW at 9 - 15 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 Friday, April 29, 2011.

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Avoid ignitions within 10 miles to the WNW through NNE of SSRAs.  For units that will smolder significantly through the night avoid burning within at least 15 miles to the WNW through NNE in or near drainages leading to SSRAs.



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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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