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, April 22, 2011       2:40 PM      Pete Parsons



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


SCHEDULING NOTE:  No forecaster will be available on Saturday, April 23rd.  Beginning Sunday, April 24th, we will transition to 7-days-a-week forecasting for the duration of the spring burning season.

SATURDAY

A weak upper-level ridge is forecast to shift eastward and extend from eastern Oregon northwestward through British Columbia by the afternoon.  The ridge will be undercut by a strengthening westerly jet stream aimed at northern California.  Clouds will increase with a slight chance of a shower.  The freezing level will briefly rise to about 7000 feet, but the air aloft will still be plenty cool enough for daytime heating to provide good mixing.  As a surface thermal trough shifts eastward, from western Oregon, into central Oregon, watch for morning light southeasterly transport winds to turn onshore in the mid to late afternoon.

OUTLOOK (SUNDAY-TUESDAY)
The weak upper-level ridge is forecast to shift well east of the region Easter Sunday, with a strengthening westerly jet stream directing a cold front onshore.  Areas of light rain and snow are likely, with the snow level dropping to around 5000 feet.  Precipitation totals could locally exceed .10 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, locally exceeding .25 inches.  The snow level will be near 4500 feet, but should drop to near the valley floors, in the wake of the cold front, Monday night.  Mixing should be good with brisk west winds.

A flat upper-level ridge is forecast to bring a drier and more stable northwesterly flow aloft on Tuesday.  Showers will taper off with temperatures remaining well below normal.  The freezing level will only rise to about 6000 feet, so afternoon mixing will be good with decreasing west to northwest winds.


2.  DISPERSION



SATURDAY

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 light and variable and controlled by local terrain.  Transport wind increases to SW to WNW at 4 - 8 mph during the evening.



Surface wind light and variable and controlled by local terrain through the day.  Surface wind increases to SW to WNW at 4 - 8 mph during the evening.



OUTLOOK:



SUNDAY

Mixing height below 1000 ft early rising to 2000 - 3000 ft by late morning rising above 5000 ft during the afternoon.  Transport wind SSW to WSW at 12 - 24 mph during the morning becoming WSW to WNW at 15 - 29 mph during the afternoon.  Surface wind SSW to WSW at 6 - 10 mph during the morning becoming WSW to WNW at 10 - 18 mph during the afternoon.



MONDAY

Mixing height 2500 - 3500 ft during the morning rising above 5000 ft during the afternoon.  Transport wind WSW to WNW at 20 - 36 mph.  Surface wind WSW to W at 10 - 22 mph.



TUESDAY

Mixing height 2200 - 3200 ft during the morning rising above 5000 ft during the afternoon.  Transport wind WNW to NW at 8 - 12 mph.  Surface wind light and variable during the morning becoming W to NW at 4 - 8 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 Saturday and Sunday, April 23 and 24, 2011.

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For Saturday:



Avoid ignitions within 15 miles in all directions of SSRAs.  For units that will smolder significantly through the night avoid burning within at least 30 miles in all directions of SSRAs.  Recommend against burning units that will smolder significantly overnight.  Complete ignitions by 6 p.m.



For Sunday:



Avoid ignitions within 12 miles to the SW through WNW of SSRAs.  For units that will smolder significantly through the night avoid burning within at least 20 miles to the S through WNW 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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