Spot Forecast
Issued by NWS Great Falls, MT
Issued by NWS Great Falls, MT
609
FNUS75 KTFX 280102
FWSTFX
Spot Forecast for Twin Sisters Fire...USFS
National Weather Service Great Falls MT
702 PM MDT Mon Jul 27 2026
Forecast is based on forecast start time of 1900 MDT on July 27.
If conditions become unrepresentative...contact the National Weather
Service.
.DISCUSSION...
An upper level ridge of high pressure will try to build over MT
over the next few days. This will result in very warm afternoon
temperatures through the week. There will be just enough
instability for a daily chance of a shower/thunderstorm. However,
precipitation will be minimal, with most showers only producing
0.01 or 0.02 inches of rainfall. The main impact from any storm
will be gusty winds and lightning.
.REST OF TONIGHT...
Sky/weather.........Partly cloudy (45-55 percent) then becoming
mostly cloudy (50-60 percent). Areas of smoke
through the night. Slight chance of showers
after 3 am.
CWR.................5 percent.
Chance of thunder...5 percent.
Min temperature.....61-66.
Max humidity........38-43 percent.
Wind (20 ft)........
Slope/valley.......Downslope winds 4 to 8 mph.
Ridgetop...........South 5 to 10 mph shifting to the southeast 10
to 15 mph late in the evening.
Mixing height.......500 ft AGL.
Transport winds.....East 5 to 10 mph shifting to the south late in
the evening.
TIME (MDT) 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM
Sky (%).........50 50 52 52 52 52 52 56 60 54 55
Weather cov.....ARS ARS ARS ARS ARS ARS ARS ARS ARS ARS ARS
Weather type....SMK SMK SMK SMK SMK SMK SMK SMK SMK SMK SMK
Tstm cov........
CWR.............0 0 0 0 0 10 10 10 10 10 10
Chc of thdr (%).0 0 0 0 0 10 10 10 0 0 0
Temp............82 78 72 70 69 68 69 68 66 66 65
RH..............24 31 35 36 37 38 37 37 39 42 42
20 FT wind dir..NE NE N W SW S S S S S SW
20 FT wind spd..5 5 5 5 5 5 5 5 5 5 5
20 FT wind gust.15 10 10 10 10 10 10 10 10 10 10
Ridge wind dir..S S SE SE SE SE SE SE SE SE S
Ridge wind spd..5 5 10 10 15 15 15 10 10 10 15
Mix hgt (kft)...3.0 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5
Transp wind dir.E NE SE E S S S S S S S
Transp wind spd.10 10 5 5 10 10 10 10 10 10 10
.TUESDAY...
Sky/weather.........Mostly sunny (45-55 percent). Areas of smoke
through the day. Slight chance of showers and
thunderstorms late in the afternoon.
CWR.................5 percent.
Chance of thunder...10 percent.
Max temperature.....87-92.
Min humidity........15-20 percent.
Wind (20 ft)........
Slope/valley.......South winds 5 to 10 mph with gusts to around 25
mph shifting to the southwest with gusts to
around 25 mph late in the afternoon. Gusty and
erratic winds expected near thunderstorms late
in the afternoon.
Ridgetop...........South 10 to 15 mph shifting to the west 15 to
20 mph late in the afternoon.
Mixing height.......10000 ft AGL.
Transport winds.....South 10 to 15 mph shifting to the southwest 15
to 20 mph late in the afternoon.
TIME (MDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........55 56 53 50 51 51 50 51 50 52 51 44
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........ SCH SCH SCH
CWR.............0 0 0 0 0 0 10 10 10 10 10 10
Chc of thdr (%).0 0 0 0 0 0 10 10 10 10 10 10
Temp............64 67 70 73 77 80 81 84 87 87 88 88
RH..............43 42 39 35 33 31 29 27 24 22 20 20
20 FT wind dir..S S S S S S S S S SW SW SW
20 FT wind spd..5 5 5 5 5 10 10 10 10 10 10 10
20 FT wind gust.10 10 10 10 15 15 20 20 25 25 20 20
Ridge wind dir..S S S S S SW SW SW SW W W W
Ridge wind spd..15 15 15 10 10 10 10 10 15 15 20 15
Mix hgt (kft)...0.5 0.5 0.5 1.5 2.5 3.0 4.5 7.5 10 9.5 7.5 7.5
Transp wind dir.S S S S S S S SW SW SW SW SW
Transp wind spd.10 10 10 10 10 10 15 15 20 20 15 15
.TUESDAY NIGHT...
Sky/weather.........Mostly clear (20-30 percent). Slight chance of
showers and thunderstorms early in the evening.
Areas of smoke through the night.
CWR.................5 percent.
Chance of thunder...15 percent.
Min temperature.....60-65.
Max humidity........37-42 percent.
Wind (20 ft)........
Slope/valley.......East winds around 10 mph becoming downslope
winds by late evening. Gusty and erratic
winds expected near thunderstorms.
Ridgetop...........West around 15 mph shifting to the north 5 to
10 mph early in the evening, then shifting to
the south.
Mixing height.......500 ft AGL.
Transport winds.....Southerly winds 10 to 15 mph.
TIME (MDT) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM
Sky (%).........31 31 31 16 16 16 22 22 22 19 19 19
Weather cov.....ARS SCH SCH PTY PTY PTY PTY PTY PTY PTY ARS
Weather type....SMK RW RW SMK SMK SMK SMK SMK SMK SMK SMK
Tstm cov........SCH SCH SCH
CWR.............10 10 10 10 10 10 0 0 0 0 0 0
Chc of thdr (%).15 15 15 10 10 10 0 0 0 0 0 0
Temp............86 84 80 74 71 70 68 69 68 66 64 64
RH..............20 24 32 35 38 39 41 39 41 42 42 42
20 FT wind dir..E E E NW NW NW SW SW SW W W W
20 FT wind spd..10 10 10 5 5 5 5 5 5 5 5 5
20 FT wind gust.20 20 20 15 15 15 15 15 15 10 10 10
Ridge wind dir..W NW N N NE E SE SE S S S S
Ridge wind spd..15 15 10 5 5 10 10 10 10 10 10 10
Mix hgt (kft)...6.0 3.5 1.0 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5
Transp wind dir.SW S SE NE N NW SE W W NW NW NW
Transp wind spd.15 10 10 5 5 5 10 10 5 5 10 10
.WEDNESDAY...
Sky/weather.........Mostly sunny (30-40 percent). Areas of smoke
early in the morning. Slight chance of showers
and thunderstorms in the afternoon.
CWR.................5 percent.
Chance of thunder...20 percent.
Max temperature.....84-89.
Min humidity........18-23 percent.
Wind (20 ft)........
Slope/valley.......Northwest winds around 10 mph shifting to the
east late in the afternoon. Gusty and erratic
winds expected near thunderstorms in the
afternoon.
Ridgetop...........Variable winds at 5 to 10 mph.
Mixing height.......8500 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 (%).........18 18 18 19 19 19 35 35 35 51 51 51
Weather cov.....ARS SCH SCH SCH SCH SCH SCH
Weather type....SMK RW RW RW RW RW RW
Tstm cov........ SCH SCH SCH SCH SCH SCH
CWR.............0 0 0 0 0 0 10 10 10 10 10 10
Chc of thdr (%).0 0 0 0 0 0 20 20 20 20 20 20
Temp............63 67 70 73 76 79 81 83 85 85 85 84
RH..............41 38 33 29 27 26 25 24 23 23 23 24
20 FT wind dir..NW NW NW N N N N N N E E E
20 FT wind spd..10 10 10 10 10 10 10 10 10 10 10 10
20 FT wind gust.15 15 15 20 20 20 20 20 20 20 20 20
Ridge wind dir..SW SW W NW NW NW NW W SW SW S SE
Ridge wind spd..10 5 5 5 5 5 5 5 5 5 5 5
Mix hgt (kft)...0.5 0.5 1.0 2.0 2.0 2.5 3.0 4.5 6.5 8.0 8.5 8.5
Transp wind dir.NW N N N N N N NW W SW SW S
Transp wind spd.10 10 10 15 15 10 10 10 15 15 15 15
$$
Forecaster...Brusda
Requested by...Clifford Reynolds
Type of request...WILDFIRE
.TAG 2618336.1/TFX
.DELDT 07/27/26
.FormatterVersion 2.0.0
.EMAIL clifford.reynolds@usda.gov