SMOKE MANAGEMENT FORECAST AND INSTRUCTIONS

SALEM FORESTRY WEATHER CENTER

OREGON DEPARTMENT OF FORESTRY

 

ISSUED: Thursday, May 1, 2025       2:30 PM      Gary Votaw

 

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

 

SHORT-TERM DISCUSSION

 

Friday will be the warmest day of the week, 10-15oF above average under mostly sunny skies.  The upper ridge moves east as S flow increases and destabilizes the air.  Expect excellent afternoon mixing with increasing S-SW transport winds.  Clouds increase late and there is a chance of showers or thundershowers by late afternoon and evening, with a cold front arriving in evening.

 

EXTENDED DISCUSSION

 

After the cold front passes by on Friday night Saturday will be much colder, temperatures 5-10oF below normal.  South flow aloft stills bring moist and unstable air for widespread showers, typically .10” to .25” of moisture and snow levels lowering to 6500-7500 feet.  Afternoon mixing conditions will be very good with mostly NNW-NNE winds.

 

The upper trough moves eastward by Sunday with drier air arriving.  But there is a chance of a few light showers in the east during morning with the snow level at 5-6000 feet.  Skies otherwise will become sunny while remaining cool.  Mixing will be very good with NNE-NE transport winds.

 

Monday will be sunny and warm as N flow aloft will be ahead of the next upper ridge due to arrive Tuesday.  Mixing again becomes very good in the afternoon with N-NE winds, weakening a little through the day.

 

2.  DISPERSION

 

FRIDAY

 

Low early mixing height below 1000 ft rising above 5000 ft by late morning and through the afternoon.  Mixing height lowers to 3700 - 4700 ft during the evening.

 

Transport wind SSE to SSW at 10 - 18 mph during the morning.  Transport wind increases to S to SSW at 15 - 25 mph during the afternoon then shifts to SW to WSW at 13 - 25 mph during the evening.

 

Surface wind SSE to SW at 4 - 8 mph during the morning.  Surface wind increases to S to SW at 9 - 15 mph during the afternoon and evening.

 

OUTLOOK:

 

SATURDAY

Mixing height below 1000 ft early rising to 1900 - 2900 ft by late morning rising above 5000 ft during the afternoon.  Transport wind N to NE at 10 - 22 mph during the morning becoming NNW to NNE at 10 - 20 mph during the afternoon.  Surface wind NW to NNE at 6 - 10 mph.

 

SUNDAY

Mixing height 1700 - 2700 ft during the morning rising above 5000 ft during the afternoon.  Transport wind NNE to NE at 14 - 28 mph.  Surface wind NNW to NNE at 10 - 16 mph.

 

MONDAY

Mixing height 3000 - 4000 ft during the morning rising above 5000 ft during the afternoon.  Transport wind N to NE at 24 - 42 mph during the morning becoming N to NE at 18 - 30 mph during the afternoon.  Surface wind NNE to NE at 10 - 22 mph.

 

3.  BURNING INSTRUCTIONS FOR ZONES 624 AND 625 INCLUDING THE WALKER

    RANGE PORTION OF ZONE 624

    - Valid for burning done Friday, May 2, 2025.

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Delay ignitions until 10 a.m.  Follow standard guidance matrix - see section 5 below - for burning units to the SSE through W of SSRAs.  For units that will smolder significantly through the night avoid burning within at least 10 miles in all directions of SSRAs.  Watch for shifting transport winds. No additional restrictions necessary. 

 

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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 between 1:30 to 2:45 p.m.

 

    http://www.odf.state.or.us/DIVISIONS/protection/fire_protection/

    Daily/lmt.htm

 

    To subscribe to or unsubscribe from the email list for this

    product, please go to the link:

    http://weather.smkmgt.com/mailman/listinfo/

 

    Please ensure your units have been planned and accomplished by

    checking: http://oregon.gov/ODF/FIRE/SMP/dailysmoke.shtml

 

    A map of planned and/or accomplished burns is located at:

    http://geo.maps.arcgis.com/apps/webappviewer/index.html

    ?id=a7e321dc8fc444b7a33fbc67bc673a3b

 

 

5.  STANDARD GUIDANCE MATRIX:

 

  * Greater than 5000 ft mixing height: Limit to 150 tons per mile

    from downwind SSRAs.

    Example: 75 tons allowed if burned a half mile from a downwind

    SSRA.

 

  * 3000 - 5000 ft mixing height: Limit to 50 tons per mile if

    burning within 5 miles of downwind SSRAs. Limit to 100 tons

    per mile if burning 5 miles or beyond downwind SSRAs.

    Example #1: 200 tons allowed if burned 4 miles from a downwind

    SSRA.

    Example #2: 500 tons allowed if burned 5 miles from a downwind

    SSRA.

 

  * Less than 3000 ft mixing height: No burning within 5 miles of

    downwind SSRAs. Limit to 60 tons per mile from downwind SSRAs.

 

  * Ensure adequate spacing between units when burning near downwind

    SSRAs.

 

  * Use of polyethylene (PE) sheeting on greater than 75 percent of

    piles in a unit with 60 percent coverage per pile will allow a

    50 percent increase in tonnage over the existing instruction tonnage

    for that zone.

 

  * All exceptions must be coordinated with the duty forecaster

    prior to ignition.

 

 

6.  BURN MONITORING:

 

    Burns over 2000 tons must be monitored (OAR 629-048-0230(3) -

    7/1/14). Monitoring of all burns is highly recommended for both

    smoke management purposes and wildfire potential.