173 FXUS65 KTFX 270027 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 627 PM MDT Sat Jul 26 2025 Aviation Section Updated. .KEY MESSAGES... - Daily rounds of showers and thunderstorms through the upcoming week, most focused on the afternoon and early evening. - The risk for stronger thunderstorms will be around most days, with gusty winds being the greatest threat most days. - As better moisture works in toward the middle of the week, concerns for localized heavy rain from thunderstorms will increase. && .DISCUSSION... /Issued 127 PM MDT Sat Jul 26 2025/ - Meteorological Overview: Southwesterly flow aloft will persist across the Northern Rockies over the upcoming week, which will promote daily afternoon and evening showers and thunderstorms. Convective initiation most days looks to be over terrain in Central and Southwest Montana, with resulting showers and thunderstorms moving northeastward with time. Looking toward the work week, better precipitable water eventually works in, which will help the more robust thunderstorms produce higher rainfall rates/amounts, though storm motion does not appear to be overly slow any specific day. The main threat with thunderstorms that form appears to be gusty winds most days, with a lesser concern for hail. Today is no exception - as thunderstorms develop across portions of Southwest Montana and shift northeastward, the risk for strong to severe wind gusts will increase. This risk continues onto the plains this evening, eventually waning after sunset. -AM - Forecast Confidence & Scenarios: Confidence in the areas with the best chance for stronger thunderstorm decreases step by step Sunday onward. These details will become more clear once convective details from the prior day play out. EFI suggests as we get deeper into the work week, convective energy increases in magnitude, becoming unusually high by Wednesday (EFI pushing above 0.9 with a SoT between 1 and 2). While a much lesser signal, QPF SoT over a similar timeframe does show pockets of 0, indicating a low end chance for anomalously high precipitation associated with the thunderstorms that are forecast to develop. -AM && .AVIATION... 27/00Z TAF Period Main concerns this evening deal with convection and gusty outflow winds. Storms/winds will likely affect GTF/HLN/LWT through mid evening. Storms could affect HFV later this evening with a 30% probability. BZN/EKS should continue to see northerly winds weaken this evening. Some models are showing some late overnight/early morning light showers but confidence is too low at this time to mention in TAFs. Otherwise, trying to time next round of convection for tomorrow afternoon with many sites not seeing convection until after 00z Mon. -DV Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .PRELIMINARY POINT TEMPS/POPS... GTF 57 84 56 83 / 60 20 30 20 CTB 51 76 52 75 / 20 20 20 30 HLN 56 86 56 86 / 40 30 30 30 BZN 51 90 51 88 / 20 20 20 20 WYS 39 81 40 83 / 10 0 0 20 DLN 47 85 48 84 / 20 30 20 20 HVR 56 84 57 83 / 40 10 30 60 LWT 54 82 52 77 / 50 20 40 50 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$ http://www.weather.gov/greatfalls