FNUS75 KTFX 221137 FWSTFX Spot Forecast for Sieben...HIDC National Weather Service Great Falls MT 537 AM MDT Sat Aug 22 2026 Forecast is based on forecast start time of 0600 MDT on August 22. If conditions become unrepresentative...contact the National Weather Service. .DISCUSSION... Scattered light showers and perhaps a rumble of thunder will move through this morning. Localized gusty winds up to 25 mph and an isolated lightning strike will be the primary hazards with this activity. A more impactful area of showers and thunderstorms will move northeastward in the afternoon and evening. Strong, gusty winds, brief heavy downpours, and some instances of hail will be possible with these later day storms. Otherwise, southwest to westerly winds will be on the increase tonight into Sunday in advance of the approaching Pacific trough. The warm, dry, and breezy to windy conditions will create elevated fire weather concerns on Sunday. There will also be some scattered thunderstorms, though most of this activity will be east of the incident site. .TODAY... Sky/weather.........Mostly cloudy (75-85 percent) then becoming mostly sunny (45-55 percent). Chance of rain showers and slight chance of dry thunderstorms in the morning. Slight chance of showers and thunderstorms in the afternoon. CWR.................5 percent. Chance of thunder...20 percent. Max temperature.....86-91. Min humidity........19-24 percent. Wind (20 ft)........ Slope/valley.......Light winds becoming south 5 to 15 mph. Gusty and erratic winds expected near and showers or thunderstorms. Ridgetop...........Southwest 15 to 20 mph, then decreasing to 10 to 15 mph in the afternoon shifting to the west late in the afternoon. Mixing height.......7500 ft AGL. Transport winds.....South 5 to 10 mph shifting to the southwest late in the afternoon. TIME (MDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM Sky (%).........75 99 94 83 89 80 63 56 58 58 57 50 Weather cov..... SCH SCH CHC SCH SCH SCH SCH SCH Weather type.... RW RW RW RW RW RW RW RW Tstm cov........ SCH SCH SCH SCH SCH SCH SCH SCH CWR.............10 10 10 10 10 10 10 10 10 10 10 10 Chc of thdr (%).10 20 20 20 20 20 20 20 20 10 10 10 Temp............61 59 61 64 71 73 77 81 84 86 87 86 RH..............61 61 62 60 45 43 37 31 26 24 24 25 20 FT wind dir..S S S SE SE S S S S S S S 20 FT wind spd..0 0 5 5 5 10 10 10 10 10 5 5 20 FT wind gust.5 5 10 10 10 15 15 15 15 15 15 15 Ridge wind dir..S SW SW SW SW SW SW SW SW W W W Ridge wind spd..15 20 20 20 20 20 15 15 15 15 10 10 Mix hgt (kft)...0.5 0.5 0.5 0.5 1.5 1.5 2.0 3.5 5.0 7.0 7.5 7.0 Transp wind dir.SE S SE S S S S S S SW W SW Transp wind spd.5 5 10 10 10 10 15 15 10 15 10 10 .TONIGHT... Sky/weather.........Mostly cloudy (75-85 percent) then becoming partly cloudy (40-50 percent). Chance of showers and thunderstorms in the evening. CWR.................35 percent decreasing to 0 percent overnight. Chance of thunder...48 percent. Min temperature.....54-59. Max humidity........87-92 percent. Wind (20 ft)........ Slope/valley.......Southerly winds 5 to 15 mph. Gusty and erratic winds expected near and showers or thunderstorms. Ridgetop...........West 10 to 15 mph shifting to the southwest 15 to 20 mph in the late evening and overnight, thenincreasing to 25 to 30 mph overnight. Mixing height.......500 ft AGL. Transport winds.....Southwesterly 5 to 15 mph. TIME (MDT) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM Sky (%).........68 72 62 72 97 87 71 70 60 43 44 47 Weather cov.....CHC CHC CHC CHC CHC Weather type....RW RW RW RW RW Tstm cov........CHC CHC CHC CHC CHC CWR.............40 40 40 40 40 40 0 0 0 0 0 0 Chc of thdr (%).50 50 40 40 30 10 0 0 0 0 0 0 Temp............85 83 79 74 71 69 67 66 64 62 60 58 RH..............26 31 39 49 58 63 68 69 75 80 82 87 20 FT wind dir..S W S SW SW S S S SE SE SE SE 20 FT wind spd..5 5 5 5 5 5 5 5 5 5 5 5 20 FT wind gust.15 15 10 15 10 10 10 10 10 10 10 10 Ridge wind dir..NW W W W SW SW S S SW SW SW SW Ridge wind spd..10 10 10 15 15 15 15 20 25 30 30 25 Mix hgt (kft)...5.0 1.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Transp wind dir.SW SW SW SW W SW S S S S S S Transp wind spd.10 10 10 10 5 5 10 10 10 10 10 10 .SUNDAY... Sky/weather.........Mostly cloudy (65-75 percent) then becoming mostly sunny (25-35 percent). Slight chance of rain showers and thunderstorms in the afternoon. CWR.................5 percent. Chance of thunder...15 percent. Max temperature.....83-88. Min humidity........16-21 percent. Wind (20 ft)........ Slope/valley.......South winds 5 to 10 mph becoming southwest around 15 mph early in the afternoon, then shifting to the west with gusts to around 30 mph late in the afternoon. Gusty and erratic winds expected near any showers or thunderstorms. Ridgetop...........Southwest 20 to 25 mph increasing to west 30 to 35 mph late in the afternoon. Mixing height.......10000 ft AGL increasing to 10500 ft AGL late in the afternoon. Transport winds.....South 10 to 15 mph increasing to southwest 20 to 25 mph late in the afternoon. TIME (MDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM Sky (%).........72 72 72 46 46 46 25 25 25 10 10 10 Weather cov..... SCH Weather type.... RW Tstm cov........ SCH CWR.............0 0 0 0 0 0 10 10 10 10 10 10 Chc of thdr (%).0 0 0 0 0 0 0 20 10 0 0 0 Temp............58 56 58 62 71 75 79 81 83 83 83 84 RH..............89 92 90 75 58 46 38 33 29 27 23 23 20 FT wind dir..S S S S S S SW SW SW W W W 20 FT wind spd..5 5 5 10 10 10 15 15 15 15 15 15 20 FT wind gust.10 10 10 15 15 15 25 25 25 30 30 30 Ridge wind dir..SW SW SW SW SW SW SW SW SW W W W Ridge wind spd..25 25 25 25 25 20 20 25 30 35 30 30 Mix hgt (kft)...0.5 0.5 0.5 1.0 2.0 3.0 5.5 8.0 10 8.5 11 10 Transp wind dir.S S S S S SW SW SW SW SW SW W Transp wind spd.10 10 10 10 15 10 15 15 20 25 25 20 $$ Forecaster...Greely Requested by...Mikkelson Type of request...WILDFIRE .TAG 2620228.0/TFX .DELDT 08/22/26 .FormatterVersion 2.0.0 .EMAIL charlie.ewart@mt.gov,mthdc@firenet.gov,braeden.mikkelson@mt.gov, tfx.ops@noaa.gov