SMOKE MANAGEMENT
FORECAST AND INSTRUCTIONS
SALEM FORESTRY
WEATHER CENTER
OREGON DEPARTMENT
OF FORESTRY
ISSUED:
Wednesday, April 30, 2025 2:30 PM Pete Parsons
1. DISCUSSION AND
FORECAST FOR THE WESTERN OREGON AREA FORECAST ZONES 601-623 and 639
SHORT-TERM DISCUSSION
An upper-level ridge builds over the region on Thursday,
bringing sunny and unseasonably warm conditions. After morning inversions, temperatures will
climb to about 15°F above average in the afternoon, providing fair mixing west
and good mixing east. Light winds turn
onshore across the coastal zones late, as the surface thermal trough shifts eastward,
to over the Cascades.
EXTENDED DISCUSSION
On Friday, the upper-level ridge progresses eastward, to
over the Rockies, with the surface thermal trough shifting into Central Oregon. Increasing onshore flow will moderate western
temperatures to about 10°F above average, while central Oregon remains 15°F
above average. Expect good afternoon mixing over the eastern zones, but only fair
mixing west. Increasing S-SW flow aloft destabilizes
the air mass, bringing a chance of showers or thundershowers to mainly the
southern zones by late in the day.
A potent upper-level trough brings cooler and cloudy conditions
on Saturday with widespread showers south and a few showers north. Expect wetting rains south (.25” - .50”), while
many northern areas receive less than .10”.
Temperatures cool to below average with the greatest negative departures
south. Expect good mixing and increasing
NW winds.
A drier and more stable NW flow aloft brings sunshine on
Sunday, helping surface temperatures recover to near average. Warmer surface temperatures and residual cool
air aloft should promote good daytime mixing with brisk NW-N winds.
2. DISPERSION
THURSDAY
Zone 601, 602,
603, 612 and 615-620 (North and South Coast Range):
MORNING
Mixing height
below 1000 ft early rising to 1300 - 2300 ft by late morning.
Transport wind
NNE to ENE at 4 - 8 mph.
Surface wind
light and variable and controlled by local terrain.
AFTERNOON
Mixing height
rising to 2700 - 3700 ft.
Transport wind
becomes light and variable and controlled by local terrain.
Surface wind similar to morning.
EVENING
Mixing height
1000 - 1700 ft.
Transport wind
increases to WSW to NW at 6 - 10 mph.
Surface wind
increases to WSW to NW at 4 - 8 mph.
Zone 605-611 and
639 (North Cascades):
MORNING
Mixing height
below 1000 ft early rising to 2000 - 3000 ft by late morning.
Transport wind E
to SE at 4 - 8 mph.
Surface wind
light and variable and controlled by local terrain.
AFTERNOON
Mixing height
rising above 5000 ft.
Transport wind
shifts to N to NE at 4 - 8 mph.
Surface wind similar to morning.
EVENING
Mixing height
2000 - 3000 ft.
Transport wind
becomes light and variable and controlled by local terrain.
Surface wind similar to afternoon.
Zone 616-623
(South Cascades):
MORNING
Mixing height
below 1000 ft early rising to 2000 - 3000 ft by late morning.
Transport wind
ESE to SSE at 4 - 8 mph.
Surface wind
light and variable and controlled by local terrain.
AFTERNOON
Mixing height
rising above 5000 ft.
Transport wind
becomes light and variable and controlled by local terrain.
Surface wind similar to morning.
EVENING
Mixing height
2000 - 3000 ft.
Transport wind
increases to WNW to NNW at 4 - 8 mph.
Surface wind
shifts to WNW to NNW at 4 - 8 mph.
OUTLOOK:
FRIDAY
Mixing height
below 1000 ft early rising to 2000 to 3000 ft by late morning rising to 3600 to
4600 ft during the afternoon. Transport
wind SSW to W at 4 - 8 mph. Surface wind
light and variable during the morning becoming SW to W at 4 - 8 mph during the
afternoon.
SATURDAY
Mixing height
2200 to 3200 ft during the morning rising to 4200 to 5000 ft during the
afternoon. Transport wind NW to NNW at
10 - 20 mph. Surface wind WNW to NNW at
5 - 9 mph.
SUNDAY
Mixing height
2500 to 3500 ft during the morning rising above 5000 ft during the
afternoon. Transport wind NNW to N at 10
- 22 mph. Surface wind NW to N at 8 - 12
mph.
3. BURNING
INSTRUCTIONS FOR ALL ZONES IN THE WESTERN OREGON AREA
- Valid for burning done Thursday, May 1,
2025.
=================================================================
Coast Range
***Avoid
ignitions before 11 a.m. in all zones.***
Zone 601 and 612
Units should be
1000 tons or less, spaced 8 miles apart, and 10 miles from downwind SSRAs. Restrict units in or near corridors to 500
tons or less.
Zone 602, 603,
and 620
Units should be
300 tons or less, spaced 8 miles apart, and 10 miles from downwind SSRAs. Limit burning in or near corridors. Higher tonnage is possible south of T35S in
Zone 620. Call the forecaster.
Zone 615 and 616
west of R8W
Units should be
1200 tons or less, spaced 8 miles apart, and 10 miles from downwind SSRAs.
Zone 616 east of
R9W
Units should be
750 tons or less, spaced 8 miles apart, and 10 miles from downwind SSRAs.
Zone 618 and 619
Use standard guidance matrix. (See section 5 below.)
Cascades
***Avoid
ignitions before 10 a.m. in all zones.***
Zone 605, 606,
620, and 622
Units should be
750 tons or less, spaced 3 miles apart, and 5 miles from downwind SSRAs. Higher tonnage is possible south of T20S in
Zone 606 - call the forecaster.
Zone 607, 608,
and 616
Units should be
1500 tons or less, spaced 3 miles apart, and 5 miles from downwind SSRAs. In zone 616 avoid ignitions north of
T24S. South of T29S higher tonnage is
possible - call the forecaster.
Zone 639, 610,
611, 617, and 623
Use standard
guidance matrix - see section 5 below.
Ensure adequate distance from downwind SSRAs for smoke to dissipate.
Siskiyous
***Avoid
ignitions before 10 a.m.***
Units should be
1500 tons or less, spaced 3 miles apart, and 5 miles from downwind SSRAs.
==============================================================
4. SPECIAL NOTES:
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
Call the smoke management duty forecaster
at (503) 945-7401 to
discuss burning. Please do not call individual's numbers to
discuss daily burning. If the forecaster is
not available,
leave a message and they will return your
call as soon as possible.
Avoid calling between 1:30 to 2:45 p.m.
The forecast is available on the Internet
at:
http://www.odf.state.or.us/DIVISIONS/protection/fire_protection/
Daily/smi.htm
Please ensure your units have been planned
and accomplished by
checking:
http://www.oregon.gov/ODF/Fire/Pages/Burn.aspx
A map of planned and/or accomplished burns
is located at:
http://geo.maps.arcgis.com/apps/webappviewer/index.html
?id=a7e321dc8fc444b7a33fbc67bc673a3b
The forecast/instruction telephone
recording is: (503) 945-7400.
To subscribe to or unsubscribe from the
email list for this
product, please go to the link:
http://weather.smkmgt.com/mailman/listinfo/
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.
Example: 300 tons allowed if burned 5 miles
from a downwind SSRA.
* 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.