SMOKE MANAGEMENT FORECAST AND INSTRUCTIONS

SALEM FORESTRY WEATHER CENTER

OREGON DEPARTMENT OF FORESTRY

 

ISSUED: Tuesday, April 29, 2025       2:30 PM      Pete Parsons

 

******************** Instruction Zones Update ***********************

The National Weather Service recently changed borders and numbering of their fire zones.  ODF will use the previous zone boundaries for smoke management and not change with these updates.

A link to ODF’s smoke forecast zones is at the bottom of the instructions in the Special Notes section. (https://www.oregon.gov/odf/fire/documents/smoke-forecast-zone-map.pdf)

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1.  DISCUSSION AND FORECAST FOR NORTHEAST FORECAST AREA ZONES 637-646

 

SHORT-TERM DISCUSSION

A drying NW-N flow aloft clears skies on Wednesday with sunny skies warming temperatures to about 5°F above average.  Daytime mixing will be good with slackening NW-N winds.

EXTENDED DISCUSSION

An upper-level ridge builds over the region on Thursday, bringing sunny and unseasonably warm conditions.  After morning inversions, temperatures will climb to 10-15°F above average, providing good afternoon mixing with light SE winds.

On Friday, the upper-level ridge progresses eastward, to over the Rockies, with increasing S-SW flow aloft destabilizing the air mass.  Temperatures should warm to about 15°F above average with a chance of showers or thundershowers by evening.  Expect good afternoon mixing with increasing SE-S winds.

A moist and unstable southerly flow aloft should bring widespread showers on Saturday, as a potent upper-level trough comes onshore into northern California.  Rainfall totals may locally exceed .25”, especially south and over higher terrain, with temperatures cooling to near average.  Expect good daytime mixing and increasing NW winds.

2.  DISPERSION

 

WEDNESDAY

 

Mixing height below 1500 ft early rising to 2500 - 3500 ft by late morning.  Afternoon mixing height rises above 5000 ft then lowers to 2000 - 3000 ft during the evening.

 

Transport wind NW to N at 4 - 8 mph.

 

Surface wind light and variable and controlled by local terrain during the morning.  Surface wind increases to NW to NNE at 4 - 8 mph during the afternoon and evening.

 

OUTLOOK:

 

THURSDAY

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

 

FRIDAY

Mixing height below 1000 ft early rising to 2500 to 3500 ft by late morning rising above 5000 ft during the afternoon.  Transport wind SSE to SSW at 8 - 12 mph.  Surface wind SE to S at 5 - 9 mph.

 

SATURDAY

Mixing height below 1000 ft early rising to 2500 to 3500 ft by late morning rising to 4000 to 5000 ft during the afternoon.  Transport wind WNW to NNW at 8 - 12 mph.  Surface wind W to NW at 4 - 8 mph.

 

3.  BURNING INSTRUCTIONS FOR NORTHEAST OREGON ZONES 637-646

    - Valid for burning done Wednesday, April 30, 2025.

    ==================================================================

 

Follow standard guidance matrix - see section 5 below - for burning units to the NW through NNE of SSRAs.  For units that will smolder significantly through the night avoid burning within at least 15 miles in all directions of SSRAs.  Verify transport winds away from SSRAs if burning in any other direction. No additional restrictions necessary. 

 

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4.  SPECIAL NOTE:

 

    The ODF forecast smoke zones differ from the NWS fire zones and

    are available at:

    https://www.oregon.gov/odf/fire/documents/smoke-forecast-zone-map.pdf

 

    The smoke management forecaster is available at (503)-

    945-7401. Please call this number and not individual's

    numbers to discuss daily burning.  For large burns (over

    2000 tons) or burns extending over a considerable period,

    please request a special forecast.  Avoid calling

    between 1:30 to 2:45 p.m.

 

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

    Daily/neo.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.