377
FNUS75 KBYZ 210031
FWSBYZ

Spot Forecast for Windmill Fire...Stillwater County
National Weather Service Billings MT
631 PM MDT Thu Aug 20 2026

Forecast is based on forecast start time of 1800 MDT on August 20.
If conditions become unrepresentative...contact the National Weather
Service.

Please contact our office if you have questions
or concerns with this forecast.

.DISCUSSION...

Hot conditions will continue into the weekend and dry conditions
will prevail into Friday night. Winds will shift out of the east
by Friday afternoon, with the most likely timeframe for the switch
between 1000 and 1400 MDT. Overnight relative humidity recoveries
will be modest to poor tonight and modest Friday night. Showers
are most likely (30% chance) after 0800 MDT Saturday and
thunderstorms are most likely (20% chance) after 1100 MDT. The
main threats will be pockets of heavy rain and erratic wind
gusts up to 45 mph.

.TONIGHT...

Sky/weather.........Partly cloudy then becoming mostly cloudy.
CWR.................0 percent.
Chance of lightning.0 percent.
Min temperature.....60-64.
Max humidity........38-42 percent.
Wind (20 ft)........
 Slope/valley.......North winds 8 to 14 mph with gusts up to 20 mph
in the early evening becoming light and variable
overnight.
 Ridgetop...........North to northwest 10 to 20 mph.
Mixing height.......Decreasing to 400 ft AGL overnight.
Transport winds.....North to northwest 10 to 20 mph.

.FRIDAY...

Sky/weather.........Mostly sunny.
CWR.................0 percent.
Chance of lightning.0 percent.
Max temperature.....84-88.
Min humidity........18-22 percent.
Wind (20 ft)........
 Slope/valley.......North winds 6 to 12 mph becoming east 8 to 14
mph with gusts up to 20 mph in the afternoon.
 Ridgetop...........North winds around 10 mph in the morning shifting
                    to east 10 to 20 mph in the afternoon.
Mixing height.......Increasing to 7000 ft AGL in the afternoon.
Transport winds.....North winds around 10 mph in the morning shifting
                    to east 10 to 20 mph in the afternoon.

.FRIDAY NIGHT...

Sky/weather.........Mostly cloudy.
CWR.................0 percent.
Chance of lightning.0 percent.
Min temperature.....58-62.
Max humidity........57-61 percent.
Wind (20 ft)........
 Slope/valley.......Northeast winds 10 to 16 mph with gusts up to
25 mph in the evening becoming light and
variable overnight.
 Ridgetop...........Northeast 15 to 25 mph becoming north 5 to 10
mph overnight.
Mixing height.......Decreasing to 400 ft AGL overnight.
Transport winds.....Northeast 10 to 20 mph becoming north 5 to 10
mph overnight.

.SATURDAY...

Sky/weather.........Mostly cloudy. Slight chance of showers through
                    the day. Slight chance of thunderstorms in the
                    afternoon.
CWR.................10 percent.
Chance of lightning.20 percent.
Max temperature.....81-85.
Min humidity........27-31 percent.
Wind (20 ft)........
 Slope/valley.......North winds 5 to 10 mph becoming southeast 8 to
14 mph in the afternoon. Gusty and erratic
                    winds expected near thunderstorms in the
                    afternoon.
 Ridgetop...........North around 10 mph becoming southeast 10 to
15 mph in the afternoon.
Mixing height.......Increasing to 3900 ft AGL in the afternoon.
Transport winds.....North around 10 mph becoming southeast 10 to
15 mph in the afternoon.

$$
Forecaster...Archer
Requested by...Nick Jacobs IC (t)
Type of request...WILDFIRE
.TAG 2620080.2/BYZ
.DELDT 08/20/26
.FormatterVersion 2.0.0
.EMAIL mtbdc@firenet.gov,dstamey@stillwatercountymt.gov