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 21, 2011       2:40 PM      Pete Parsons



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


FRIDAY

A weak upper-level ridge of high pressure is forecast to bring generally dry and warmer conditions. After a cold start, with morning minimums locally near 20 degrees, mostly sunny skies should warm afternoon surface temperatures to within about 5 degrees of normal.  A weak disturbance, in an undercutting westerly jet stream, may bring some afternoon clouds. The freezing level will only rise to about 7000 feet, so afternoon heating will provide good mixing.  Transport winds will turn mostly light southeasterly.

OUTLOOK (SATURDAY-MONDAY)
The upper-level ridge appears as if it will remain strong enough to bring another generally dry day on Saturday.  However, a weather system moving across northern California will spread more clouds across the region with a slight chance of a shower.  The freezing level will drop slightly, to near 6500 feet, with good daytime mixing.  Watch for light southeasterly transport winds to turn onshore in the late afternoon.

The upper-level ridge is forecast to weaken and shift east of the region Easter Sunday, with a strengthening westerly jet stream directing a weak cold front onshore.  Light rain and snow are likely, with the snow level dropping to around 5000 feet.  Precipitation totals could locally exceed .25 inches.  Mixing should be good with increasing southwest to west transport winds.

A stronger cold front is forecast to come onshore Sunday night and early Monday.  This system will have a strong jet stream associated with it and more significant precipitation.  Look for the snow level to drop to near the valley floors during the day.  Mixing should be good with strong westerly surface and transport winds.


2.  DISPERSION



FRIDAY

Mixing height below 1000 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 SE to S at 4 - 8 mph throughout the morning and afternoon.  Transport wind shifts to ENE to ESE at 4 - 8 mph during the evening.



Surface wind light and variable and controlled by local terrain.



OUTLOOK:



SATURDAY

Mixing height below 1000 ft early rising to 3000 - 4000 ft by late morning rising above 5000 ft during the afternoon.  Transport wind E to SE at 4 - 8 mph during the morning becoming light and variable during the afternoon.  Surface wind light and variable.



SUNDAY

Mixing height below 1000 ft early rising to 3000 - 4000 ft by late morning rising above 5000 ft during the afternoon.  Transport wind WSW to WNW at 10 - 20 mph.  Surface wind WSW to WNW at 8 - 12 mph.



MONDAY

Mixing height below 1000 ft early rising to 3800 - 4800 ft by late morning rising above 5000 ft during the afternoon.  Transport wind WSW to W at 20 - 36 mph.  Surface wind WSW to WNW at 10 - 22 mph.



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 22, 2011.

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Avoid ignitions within 15 miles to the E through SSW of SSRAs.  For units that will smolder significantly through the night avoid burning within at least 30 miles to the ENE through SSW in or near drainages leading to SSRAs.  Verify transport winds away from SSRAs if burning in any other direction.  Watch for shifting transport winds.  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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