SILVERTON HILLS FIELD BURNING FORECAST
OREGON DEPARTMENT OF FORESTRY WEATHER OFFICE
8:40 AM PDT THU AUG 28, 2025
*** Final forecast of the 2025 field-burning season ***
WEATHER DISCUSSION:
The upper trough that gave us some thunderstorms Wednesday will be over Washington today while another trough is well offshore. That will provide weak SW flow aloft and a similar wind at the surface in afternoon. Mostly sunny skies will warm the area close to 90oF. Onshore flow has improved air quality across the valley and should remain good today.
BURN ADVISORY:
Recommended times for agricultural burning are from 1 p.m. until 6 p.m.
Prep burning is not allowed.
Field burning is done for the season.
(See “Notes” below for difference between field burning
and Agricultural burning)
TODAY’S FORECAST:
Mostly sunny and very warm.
Salem's high temperature today will be near 90°F (average is 82°F).
Relative humidity: Dropping below 60% about 11 a.m.; 33% by 5 p.m.
Surface winds: S-SW 1-3 mph this morning; SW-WSW 4-7 mph this afternoon.
Transport winds: SW 3-6 mph this morning; WSW 5-8 mph in the afternoon.
Mixing height: Rising to 3000 feet at 1 p.m. and to 5000 feet by 5 p.m.
Salem’s sunset tonight: 7:55 p.m.
(Salem Airport data for Wednesday, August 27th: High/Low 87/62°F; Rain: Trace)
(Maximum Ventilation Index expected today: 40)
EXTENDED DISCUSSION:
Southwest flow aloft continues Friday and through the weekend as the offshore trough very slowly moves toward the Washington coast. Partly to mostly sunny skies, dry, and seasonably warm conditions will persist while high temperatures reach upper 80s on Friday then lower 80s Saturday and Sunday.
The trough is expected to move northward early next week while the ridge rebounds somewhat over Oregon throughout the week. Sunny, dry and very warm conditions will result in temperatures reaching the lower 90s, probably by Tuesday.
The National Weather Service’s digital forecast is available at:
Notes:
1. Mixing height, as used here, is the lowest height at which the
potential temperature exceeds the potential temperature at the
surface. As a practical matter it is the approximate height to
which a smoke plume will rise assuming good ignition, dry fuels,
and winds less than about 15 mph.
2. Transport winds are a layer average through the mixing height,
weighted slightly toward the winds at the top of the layer.
3. Ventilation Index is the height of the mixing layer (ft) times
the transport wind speed (mph) divided by 1000.
4. Surface wind direction is the general expected wind direction.
At a specific point surface winds are highly dependent on local
terrain conditions.
5. In accordance with OAR 837-110-0090, all field burning shall be
banned when any two of the following criteria are present:
A. Temperature of 95 degrees Fahrenheit or above
B. Relative humidity of 30 percent or below
C. Wind speed of 15 miles per hour or higher
6. Agricultural burning: Burning of any agricultural waste generated
by an agricultural operation that uses or intends to use land
primarily for the purpose of obtaining profit by raising,
harvesting, and selling crops or animals. Prohibited materials
such as tires cannot be burned, even in an agricultural setting.
If you make your primary living from an agricultural operation,
you are considered an agricultural operator and can agricultural
burn. If you don't make your primary living from the agricultural
operation, you are a backyard burner and subject to the rules of
backyard burning. Contact your local fire district for
information about backyard burning.
7. Open field burning: Burning of any grass seed or cereal grain
crops, or associated residue, including steep terrain and species
identified by the Director of Agriculture, or any “emergency” or
“experimental” burning (ORS 603-077-0105(29)).
8. Preparatory (prep) burning: A type of field burning where
controlled burning of portions of selected fields is conducted
for the specific purpose of reducing the fire hazard potential
or other conditions which would otherwise inhibit rapid ignition
burning when the field is subsequently open burned
(ORS 603-077-0105(34)).
9. Test fires: A type of field burning where individual field burns
are specifically authorized by the Department for the purpose of
determining or monitoring atmospheric dispersion conditions (ORS
603-077-0105(54)).
This forecast is provided under an agreement between the Oregon Department
of Agriculture (ODA) and the Oregon Department of Forestry (ODF). For
information contact ODA at 503-986-4701.
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Gary Votaw
ODF Meteorologist