117 FXUS65 KTFX 110802 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 202 AM MDT Mon Aug 11 2025 .KEY MESSAGES... - A weak cold front will stall along the Island Ranges of Central Montana, with slightly cooler temperatures over the plains of Central and North Central Montana today while the valleys of Central and Southwest Montana warm further. - Isolated to widely scattered showers and thunderstorms are expected along and behind the cold front through this evening. - Increasing west to south winds are expected on Tuesday and Wednesday, with temperatures warming into the mid-80s to mid-90s both days. && .DISCUSSION... Northwest flow aloft will prevail across the Northern Rockies through this evening as upper level ridging over the Pacific attempts, but largely fails, to builds eastward. At the surface a weak "cold" front will advance south and across North Central and portions of Central Montana through the morning hours before stalling along the northern slopes of the Island Ranges south of the Montana Hwy 200 corridor. Isolated to widely scattered showers and thunderstorms will develop along and behind this cold front, in addition to the higher terrain as far south as the I-90 corridor, with showers and storms lingering into the late afternoon/early evening hours. High temperatures in wake of the cold front over the plains of Central and North Central Montana will be some 5-10 degrees cooler than on Sunday, with the valleys of Central and Southwest Montana being 3-6 degrees warmer thanks to the cold front stalling further to the north. By this evening a shortwave over Northern British Columbia and the Gulf of Alaska will begin to dig south, which will cause the upper level ridge over the Pacific Northwest to collapse and flatten out. Upper level flow over the Northern Rockies will back to the west through the day on Tuesday due to the flattening ridge, with a subtle wave sliding east and over Southwest Montana through the afternoon/evening hours on Tuesday. Isolated showers and thunderstorms will be possible across Southwest Montana thanks to this shortwave sliding through the zonal flow, with otherwise dry conditions expected elsewhere. High temperatures on Tuesday will climb above normal across all locations thanks to increasing west surface winds, with breezy and gusty conditions expected along the Rocky Mountain Front and Montana Hwy 200 corridor. The aforementioned shortwave from the Gulf of Alaska and Northern British Columbia will dig into the Pacific Northwest by Wednesday, with strong warm air advection overspreading the Northern Rockies through the day. Not only will this strong push of warm air help to to warm most location an additional 2-5 degrees as compared to Tuesday, but also help support increasing south to west winds within the north-south orientated valleys of Southwest and Central Montana as the upper level flow backs further to the southwest. Continued breezy and gusty winds will occur along the Rocky Mountain Front and Montana Hwy 200 corridor over this same timeframe. The upper level shortwave will then slide east and across the Northern Rockies and Southern Canada through the day on Thursday, with a cold front diving southeast across North Central Montana through Wednesday evening. This cold front, much like today`s (Monday) will once stall across Central Montana; however, this time slightly further south to around the US Hwy 12 corridor. Cooler temperature can be expected in wake of this front, with continued above normal temperatures points further south across Southwest Montana. Overall dry condtions will occur from Wednesday through Thursday, but isolated showers and storms can`t be ruled out. Relatively moist, southwest flow looks to develop from Friday through the upcoming weekend over the Northern Rockies, with better chances for showers and thunderstorms across most locations. Temperatures will hover near to slightly below normal beneath this unsettled pattern. - Moldan && .AVIATION... 11/06Z TAF Period VFR conditions will prevail at all terminals during this TAF Period. The primary concern for this TAF period is a wind shift from southwesterly to northerly at the KCTB, KHVR, KGTF, KHLN, and KLWT terminals in a north to south fashion beginning around 11/10Z for the KCTB and KHVR terminals and around 11/14Z for the KGTF, KHLN, and KLWT terminals. Winds will shift from southerly to northerly at the KEKS, KBZN, and KWYS terminals during the duration of this TAF period. There is a 15% chance for showers and thunderstorms at the KLWT terminal between 11/18Z and 12/00Z There will be isolated instances of low-level wind shear across North-central Montana between now and 11/12Z. -IG Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .PRELIMINARY POINT TEMPS/POPS... GTF 79 53 91 57 / 20 10 10 0 CTB 73 54 87 56 / 20 20 0 0 HLN 85 55 91 56 / 10 10 10 10 BZN 86 50 91 52 / 10 10 10 10 WYS 80 39 83 40 / 10 10 20 10 DLN 82 48 88 50 / 0 0 20 10 HVR 78 55 87 56 / 20 10 10 0 LWT 75 53 85 54 / 20 20 10 10 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$ http://www.weather.gov/greatfalls