635 FXUS65 KTFX 131043 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 443 AM MDT Wed Aug 13 2025 Aviation Section Updated. .KEY MESSAGES... - Hot, dry, and windy conditions are expected today across Southwest through North Central Montana. - Isolated to widely scattered showers and thunderstorms are possible across extreme Southwest Montana near the Idaho border and North Central Montana north of the US Hwy 2 corridor from this afternoon through Thursday. - Brief cool down will occur in wake of a cold front on Thursday over the plains of Central and North Central Montana, with temperatures moderating back to near normal on Friday. && .DISCUSSION... /Issued 151 AM MDT Wed Aug 13 2025/ - Meteorological Overview: Zonal flow through this afternoon will begin to back to the southwest as a shortwave over Southern British Columbia and the Pacific Northwest slides east and over the Northern and Canadian Rockies from this evening through Thursday morning. At the surface a cold front will being to plunge south along the Canadian Rockies in Alberta this evening; with this front moving through North Central Montana by the late evening hours tonight and Central Montana through the mid-morng hours on Thursday. While this front will eventually move through Southwest Montana late Thursday afternoon/evening it will be significantly weaker/modified, with little to no noticeable temperature changes. Gusty southwest to west winds will be experienced across all locations prior to the passage of the aforementioned cold front today through Thursday, with the strongest winds expected along the Rocky Mountain Front and in the north-south valleys of Southwest Montana. Strong warm air advection ahead of the shortwave will help to push temperatures into the upper 80s to mid-90s today, with temperatures ranging from the upper 60s to upper 70s over the plains of Central and North Central Montana to the mid-80s to near 90 degrees in the valleys of Central and Southwest Montana on Thursday. Predominately dry conditions are expected despite the passage of the cold front and upper level shortwave; however, isolated to scattered showers and storms can`t be ruled out southeast of a Dillon to Bozeman line either day or along and mainly north of the US Hwy 2 corridor during the morning hours on Thursday. Near to above normal temperatures will quickly return to the Northern Rockies by Friday and persisting through next week as southwesterly flow aloft develops over the Northern Rockies as upper level ridging builds west from the Northern through Southern High Plains of the CONUS to the Great Basin. Best opportunity for showers and thunderstorms looks to occur from Sunday afternoon through Sunday night as a shortwave lifts northeast within the flow, with otherwise limited chances for precipitation. - Moldan - Forecast Confidence & Scenarios: Gusty Winds from this morning through Thursday afternoon: Anomalously (1 to 2.5 standard deviations above normal) strong winds for mid-Augst, particularly at H700 where wind speeds of 20-40kts will be common over much of Southwest through North Central Montana, will overspread the Northern Rockies from the mid-morning hours today through Thursday afternoon. Mixing, particularly from the late morning hours through this evening, and then with the passage of a cold front Wednesday night/Thursday morning will help to translate these stronger winds to the surface. Latest NBM probabilistic guidance supports a 80+% chance for wind gusts of 30 mph or greater for areas west of an Inverness, to Stanford, to White Sulphur Springs, to Bozeman, to West Yellowstone line through the day today, with a 40-70% chance for areas east of this line. The probability for wind gusts in excess of 40 mph through this same timeframe is generally less than an 50% chance across most areas, with the exception of the wind prone north-south valleys in Southwest Montana and along the Rocky Mountain Front where a 60-90% chance exists. By Thursday the threat for widespread gusty winds will have pushed south to all but Southwest and portions of Central Montana, mainly south of the US Hwy 12 corridor, with the north-south orientated valleys once again having the highest probabilities for wind gusts in excess of 30 mph and 40 mph at 90+% and 50-60% chances respectively. - Moldan && .AVIATION... 13/12Z TAF Period Southwest to west surface winds will increase across all terminals through 15-18z this morning, with a period of strong and gusty winds then expected between 18-24z this afternoon before gradually decreasing thereafter. Wind gusts of between 25-35kts will be common at the KCTB, KGTF, KHLN, KBZN, KEKS, and KWYS terminals throughout this timeframe. Isolated to widely scattered showers and thunderstorms developing over the higher terrain of Southwest Montana and Northern Idaho after 18z this afternoon will drift east to northeast and near the KEKS and KWYS terminals between generally 21-24z. While VFR conditions are expected to prevail throughout the entire 1312/1412 TAF period a brief period of low-VFR conditions are possible beneath or near the showers or thunderstorms. Mountain obscuration is expected to be limited to Southwest Montana over the next 18-24 hours. - Moldan Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .FIRE WEATHER... Fire weather concerns will be elevated today with very warm afternoon temperatures and low afternoon humidity combined with breezy to windy conditions across much of the area. The most critical conditions are expected across southwest MT where fuels are drier. Further north across most of central/north-central MT, fuels/fire danger are not at critical thresholds following recent precipitation, but the very warm, dry and windy conditions will bring an elevated risk for fire spread in areas where fuels may be locally more receptive. Hoenisch && .PRELIMINARY POINT TEMPS/POPS... GTF 93 56 80 52 / 0 10 10 0 CTB 88 51 69 50 / 0 20 20 10 HLN 94 55 87 53 / 10 0 0 0 BZN 94 50 91 48 / 20 10 10 0 WYS 84 39 82 38 / 30 20 20 20 DLN 90 48 88 46 / 20 0 0 0 HVR 95 56 76 52 / 0 10 20 0 LWT 89 54 77 50 / 0 0 10 10 && .TFX WATCHES/WARNINGS/ADVISORIES... && $$ http://www.weather.gov/greatfalls