SMOKE MANAGEMENT FORECAST AND INSTRUCTIONS

SALEM FORESTRY WEATHER CENTER

OREGON DEPARTMENT OF FORESTRY

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

******************** 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

An upper-level ridge centered just to the east of the region will provide S flow, sunny skies and a very warm Friday, around 15^oF above average. Afternoon mixing becomes excellent with SE-SSW winds but turning NW and increasing for western zones in evening. Clouds will increase in the evening as a cold front enters the area and there is a chance of overnight showers or thundershowers.

EXTENDED DISCUSSION

Following the cold front Saturday will be much colder, temperatures a little below normal. South flow aloft brings moist and unstable air for widespread showers, typically .10” to .25” of moisture. Mixing will become very good in the afternoon with NW-N winds.

An upper trough will still be over the region by Sunday but bringing drier and still cool air into the area. Partly sunny skies allow for very good afternoon mixing with NW-N winds.

On Monday N flow aloft will be ahead of the next upper ridge due to arrive Tuesday. Weather will be sunny and warmer for Monday. Mixing will again be very good in the afternoon with N-NNE transport winds.

2. DISPERSION

FRIDAY

Zone 640, 642, and 644 West of R35E:

Low early mixing height below 1000 ft rising to 4100 - 5000 ft during the morning. Mixing height rises to above 5000 ft during the afternoon then lowers to 1700 - 2700 ft during the evening.

Transport wind SSE to SSW at 10 - 20 mph throughout the morning and afternoon. Transport wind shifts to NW to NNW and increases to 16 - 30 mph during the evening.

Surface wind SE to SSW at 4 - 8 mph throughout the morning and afternoon. Surface wind shifts to WNW to NNW and increases to 10 - 18 mph during the evening.

Zone 637, 643, 645, 646, and 644 East of R34E:

Low early mixing height below 1000 ft rising to 4300 - 5000 ft during the morning. Mixing height rises to above 5000 ft during the afternoon then lowers to 3800 - 4800 ft during the evening.

Transport wind SSE to S at 10 - 22 mph during the morning and afternoon. Transport wind becomes light and variable and controlled by local terrain during the evening.

Surface wind ESE to SSE at 5 - 9 mph during the morning and afternoon. Surface wind becomes light and variable and controlled by local terrain during the evening.

OUTLOOK:

SATURDAY

Mixing height 1900 to 2900 ft during the morning, rising to 3900 to 4900 ft during the afternoon. Transport wind NW to N at 8 - 14 mph. Surface wind WNW to N at 5 - 7 mph.

SUNDAY

Mixing height 1500 to 2500 ft early rising to 2800 to 3800 ft during the morning then rising to 4500 to 5000 ft during the afternoon. Transport wind NW to N at 8 - 14 mph during the morning becoming NW to N at 12 - 22 mph during the afternoon. Surface wind WNW to NNW at 6 - 10 mph during the morning becoming NW to NNW at 10 - 18 mph during the afternoon.

MONDAY

Mixing height below 1000 ft early rising 3500 to 4500 ft during the morning then rising to 4500 to 5000 ft during the afternoon. Transport wind N to NNE at 18 - 32 mph. Surface wind NNW to NNE at 9 - 15 mph during the morning becoming NNW to NNE at 12 - 22 mph during the afternoon.

3. BURNING INSTRUCTIONS FOR NORTHEAST OREGON ZONES 637-646

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

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Zone 640, 642, and 644 West of R35E:

Delay ignitions until 10 a.m.  Follow standard guidance matrix - see section 5 below - for burning units in all directions 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.

Zone 637, 643, 645, 646, and 644 East of R34E:

Delay ignitions until 10 a.m.  Follow standard guidance matrix - see section 5 below - for burning units to the SE through WNW of SSRAs. For units that will smolder significantly through the night avoid burning within at least 10 miles in all directions of SSRAs. 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.