FNUS75 KTFX 231123 FWSTFX Spot Forecast for Sieben...HIDC National Weather Service Great Falls MT 523 AM MDT Sun Aug 23 2026 Forecast is based on forecast start time of 0600 MDT on August 23. If conditions become unrepresentative...contact the National Weather Service. .DISCUSSION... A surface front will bring gusty westerly winds and elevated fire weather conditions today. There will also be a few stronger widely scattered showers and thunderstorms that develop over or near the I15 corridor early this afternoon. The most widespread activity should occur east of the incident site, with around 20% chance for showers or storms at Sieben. If a storm does develop, it will be capable of producing strong, erratic wind gusts and hail in addition to cloud to ground lightning. Cooler, drier, and less windy conditions move in Monday and Tuesday before temperatures warm up and shower and thunderstorm activity returns heading towards the latter part of the week. .TODAY... Sky/weather.........Mostly sunny (30-40 percent). Slight chance of showers and thunderstorms in the afternoon. CWR.................5 percent. Chance of thunder...20 percent. Max temperature.....82-87. Min humidity........17-22 percent. Wind (20 ft)........ Slope/valley.......Southerly winds 5 to 10 mph shifting to the west 10 to 20 mph with gusts to around 30 mph by the afternoon. Gusty and erratic winds near any shower or storm. Ridgetop...........Southwest 25 to 30 mph. Mixing height.......9000 ft AGL. Transport winds.....South 10 to 15 mph becoming southwest and increasing 20 to 25 mph in the afternoon. TIME (MDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM Sky (%).........33 60 32 26 31 27 16 14 16 21 18 8 Weather cov..... SCH SCH SCH SCH Weather type.... RW RW RW RW Tstm cov........ 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 0 10 10 10 0 0 Temp............57 56 58 62 70 75 78 81 82 82 84 82 RH..............97 98 93 78 61 50 42 37 33 30 26 24 20 FT wind dir..S S S S S S SW W W W W W 20 FT wind spd..5 5 5 10 10 10 10 15 15 15 15 15 20 FT wind gust.10 10 10 15 15 20 25 25 30 30 25 Ridge wind dir..SW SW SW SW SW SW SW SW SW W W W Ridge wind spd..25 25 30 25 25 25 25 25 30 30 30 30 Mix hgt (kft)...0.5 0.5 0.5 1.0 1.5 3.0 5.0 7.0 8.5 9.0 8.0 7.5 Transp wind dir.S S S S S SW SW SW SW W W W Transp wind spd.10 10 10 10 10 10 15 20 25 25 25 25 .TONIGHT... Sky/weather.........Mostly clear (5-15 percent). CWR.................0 percent. Chance of thunder...0 percent. Min temperature.....48-53. Max humidity........52-57 percent. Wind (20 ft)........ Slope/valley.......West winds 10 to 20 mph decreasing to around 5 mph. Ridgetop...........West 30 to 35 mph decreasing to around 20 mph. Mixing height.......500 ft AGL. Transport winds.....West 15 to 20 mph decreasing to 5 to 10 mph. TIME (MDT) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM Sky (%).........5 6 8 6 14 11 8 11 12 9 10 10 Weather cov..... PTY PTY PTY PTY Weather type.... 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............82 80 76 71 68 65 62 60 58 56 53 52 RH..............25 24 25 28 31 34 37 40 44 47 51 56 20 FT wind dir..W W W W W W W W W W SW SW 20 FT wind spd..15 15 15 10 10 5 5 5 5 5 5 5 20 FT wind gust.25 25 25 20 20 15 10 10 Ridge wind dir..W W W W W W W W W W W W Ridge wind spd..30 30 30 35 35 35 30 30 30 30 25 25 Mix hgt (kft)...7.0 5.0 1.5 1.0 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Transp wind dir.W W W W W W W W W W W W Transp wind spd.20 20 15 10 10 5 5 5 5 5 5 5 .MONDAY... Sky/weather.........Sunny (10-20 percent). CWR.................0 percent. Chance of thunder...0 percent. Max temperature.....80-85. Min humidity........13-18 percent. Wind (20 ft)........ Slope/valley.......Southwest winds around 5 to 10 mph becoming west in the afternoon. Ridgetop...........West 15 to 20 mph decreasing to 10 to 15 mph. Mixing height.......9000 ft AGL. Transport winds.....West 5 to 10 mph increasing to around 15 mph in the afternoon. TIME (MDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM Sky (%).........21 21 21 4 4 4 5 5 5 8 8 8 Weather cov..... Weather type.... 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............51 50 53 58 66 70 73 76 80 81 82 82 RH..............57 59 54 46 38 34 27 23 20 18 17 17 20 FT wind dir..S S S SW SW SW W W W W W W 20 FT wind spd..5 5 5 5 5 5 5 5 5 5 5 5 20 FT wind gust.10 10 10 10 10 10 15 15 15 15 15 15 Ridge wind dir..W W W W W W W W W W W W Ridge wind spd..25 25 25 25 20 15 10 10 10 15 15 15 Mix hgt (kft)...0.5 0.5 0.5 1.5 2.5 4.0 5.5 7.0 8.0 7.5 9.0 8.0 Transp wind dir.W SW SW W W W W W W W W W Transp wind spd.5 5 5 5 10 10 10 15 15 15 15 15 $$ Forecaster...Greely Requested by...Mikkelson Type of request...WILDFIRE .TAG 2620228.1/TFX .DELDT 08/23/26 .FormatterVersion 2.0.0 .EMAIL braeden.mikkelson@mt.gov,charlie.ewart@mt.gov,mthdc@firenet.gov, tfx.ops@noaa.gov