Spot Forecast
Issued by NWS Great Falls, MT
Issued by NWS Great Falls, MT
579
FNUS75 KTFX 270206
FWSTFX
Spot Forecast for Twin Sisters Fire...USFS
National Weather Service Great Falls MT
806 PM MDT Sun Jul 26 2026
Forecast is based on forecast start time of 2000 MDT on July 26.
If conditions become unrepresentative...contact the National Weather
Service.
.DISCUSSION...
Southwest flow aloft will continue to bring in hot conditions into
the week. This evening, there is a low chance (15%) for a shower
or thunderstorm to pass over the fire through 2300. Gusty, erratic
winds will be the main hazard with any shower or thunderstorm.
Critically low afternoon humidities below 20% along with poor overnight
recoveries continue into the first half of the week. There`s a 10%
chance for a shower or thunderstorm Monday, but better chances
stay off to the southeast.
.REST OF TONIGHT...
Sky/weather.........Partly cloudy (30-40 percent). Slight chance of
showers and thunderstorms early in the evening. Areas
of smoke through the night.
CWR.................5 percent.
Chance of thunder...5 percent.
Min temperature.....63-68.
Max humidity........30-35 percent.
Wind (20 ft)........
Slope/valley.......South winds around 10 mph shifting to the
northwest early in the morning. Gusty and
erratic winds expected near thunderstorms early
in the evening.
Ridgetop...........South 0 to 5 mph shifting to the southwest after
3 am, shifting to the northwest early in the
morning.
Mixing height.......500 ft AGL.
Transport winds.....South around 10 mph shifting to the northwest
overnight.
TIME (MDT) 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM
Sky (%).........32 36 29 34 29 44 40 43 35 32
Weather cov.....ARS ARS ARS ARS ARS ARS ARS ARS ARS ARS
Weather type....SMK SMK SMK SMK SMK SMK SMK SMK SMK SMK
Tstm cov........SCH
CWR.............10 10 10 10 0 0 0 0 0 0
Chc of thdr (%).10 10 10 10 0 10 10 0 0 0
Temp............83 76 73 72 72 72 71 68 67 66
RH..............29 32 34 34 35 34 35 35 34 33
20 FT wind dir..S S SW SW W W NW NW NW NW
20 FT wind spd..10 10 10 5 5 5 10 10 10 15
20 FT wind gust.15 15 15 10 10 10 15 15 15 20
Ridge wind dir..W W SW S S S S S SW NW
Ridge wind spd..5 0 5 5 10 10 5 0 5 10
Mix hgt (kft)...0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5
Transp wind dir.S S SW SW NW NW NW NW NW NW
Transp wind spd.10 10 10 10 10 10 10 15 15 15
.MONDAY...
Sky/weather.........Sunny (20-30 percent). Areas of smoke.
CWR.................0 percent.
Chance of thunder...Less than 5 percent.
Max temperature.....84-89.
Min humidity........13-18 percent.
Wind (20 ft)........
Slope/valley.......Northwest winds 10 to 15 mph shifting to the
northeast late in the afternoon.
Ridgetop...........Northwest 10 to 15 mph shifting to the
southwest late in the afternoon.
Mixing height.......7500 ft AGL.
Transport winds.....North 10 to 15 mph shifting to the southwest
late in the afternoon.
TIME (MDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........31 32 34 36 37 38 12 20 20 12 21 28
Weather cov.....ARS ARS ARS ARS ARS ARS ARS ARS ARS ARS ARS ARS
Weather type....SMK SMK SMK SMK SMK SMK SMK SMK SMK SMK SMK SMK
Tstm cov........
CWR.............0 0 0 0 0 0 0 0 0 0 0 0
Chc of thdr (%).0 0 0 0 0 0 0 0 0 0 0 0
Temp............66 69 71 72 76 78 79 81 84 85 86 86
RH..............31 30 27 25 23 21 20 19 18 18 18 19
20 FT wind dir..NW NW NW N N N N NE NE NE NE E
20 FT wind spd..15 10 10 10 10 10 10 10 10 10 10 10
20 FT wind gust.20 15 15 15 15 15 20 20 20 20 20 20
Ridge wind dir..N N NW NW NW W W W SW SW SW W
Ridge wind spd..15 15 15 10 10 5 5 5 10 10 15 15
Mix hgt (kft)...0.5 0.5 1.0 2.0 2.5 3.0 3.5 4.5 5.5 6.5 7.0 7.5
Transp wind dir.NW N N N N N N NW W SW SW SW
Transp wind spd.15 15 10 10 10 10 10 10 10 10 15 15
.MONDAY NIGHT...
Sky/weather.........Partly cloudy (25-35 percent). Areas of smoke.
CWR.................5 percent.
Chance of thunder...10 percent.
Min temperature.....60-65.
Max humidity........28-33 percent.
Wind (20 ft)........
Slope/valley.......Southeast winds around 10 mph shifting to the
south in the late evening and overnight.
Ridgetop...........South 10 to 15 mph shifting to the west
overnight, shifting to the northwest early in
the morning.
Mixing height.......500 ft AGL.
Transport winds.....Variable winds around 10 to 15 mph.
TIME (MDT) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM
Sky (%).........28 28 28 27 27 27 34 34 34 26 26 26
Weather cov.....ARS ARS ARS ARS ARS ARS ARS ARS ARS ARS ARS ARS
Weather type....SMK SMK SMK SMK SMK SMK SMK SMK SMK SMK SMK SMK
Tstm cov........
CWR.............10 10 10 10 10 10 10 10 10 10 10 10
Chc of thdr (%).0 10 10 0 0 10 0 10 10 0 0 0
Temp............85 82 79 72 69 69 68 69 67 64 64 63
RH..............19 21 25 28 29 29 30 29 30 32 32 33
20 FT wind dir..SE SE SE S S S S S S SW SW SW
20 FT wind spd..10 10 10 10 10 10 10 10 10 10 10 10
20 FT wind gust.20 20 20 15 15 15 15 15 15 15 15 15
Ridge wind dir..W SW S S S S S SW W W W NW
Ridge wind spd..15 10 10 10 10 10 10 10 10 5 10 10
Mix hgt (kft)...7.0 4.5 1.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5
Transp wind dir.SW NW SE E NW NW S W SW SE NW NW
Transp wind spd.15 10 10 10 10 10 10 10 10 15 10 15
.TUESDAY...
Sky/weather.........Sunny (5-15 percent). Areas of smoke early in
the morning.
CWR.................0 percent.
Chance of thunder...Less than 5 percent.
Max temperature.....88-93.
Min humidity........12-17 percent.
Wind (20 ft)........
Slope/valley.......Light and variable, becoming west 10 mph in the
afternoon.
Ridgetop...........North 5 to 10 mph shifting to the southwest late
in the morning increasing to 10 to 15 mph late in
the afternoon.
Mixing height.......9500 ft AGL increasing to 10500 ft AGL late in
the afternoon.
Transport winds.....West around 10 mph shifting to the northwest
early in the morning, then shifting to the
southwest in the late morning and afternoon.
TIME (MDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........19 19 19 8 8 8 4 4 4 4 4 4
Weather cov.....ARS
Weather type....SMK
Tstm cov........
CWR.............0 0 0 0 0 0 0 0 0 0 0 0
Chc of thdr (%).0 0 0 0 0 0 0 0 0 0 0 0
Temp............63 66 69 73 76 79 82 85 87 88 89 89
RH..............33 32 30 27 26 26 26 24 22 20 18 16
20 FT wind dir..SW SW SW W W W E E E W W W
20 FT wind spd..10 10 10 5 5 5 10 10 10 10 10 10
20 FT wind gust.15 15 15 10 10 10 15 15 15 20 20 20
Ridge wind dir..N N N N NW W SW SW SW SW SW W
Ridge wind spd..10 5 5 5 0 0 0 5 10 10 15 15
Mix hgt (kft)...0.5 0.5 1.0 1.5 2.5 3.5 5.0 7.0 9.5 11 11 9.0
Transp wind dir.W NW NW W W SW SW SW SW SW W W
Transp wind spd.10 10 10 10 10 10 10 15 15 15 15 15
$$
Forecaster...Wilson
Requested by...Clifford Reynolds
Type of request...WILDFIRE
.TAG 2618336.0/TFX
.DELDT 07/26/26
.FormatterVersion 2.0.0
.EMAIL clifford.reynolds@usda.gov, tfx.ops@noaa.gov