291 FXUS65 KTFX 032031 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 231 PM MDT Tue Jun 3 2025 .KEY MESSAGES... - Daily chances for showers and storms through the work week, with the highest coverage of showers and storms expected today and Wednesday. - Below normal temperatures through Wednesday will gradually warm to above normal temperatures by the end of the work week with warmer temperatures lasting through at least early next week. - Predominately light winds are expected through Thursday. && .DISCUSSION... - Meteorological Overview: Moist, and unstable, northwest flow aloft will help to support daily chances for showers and thunderstorms across much of Southwest through North Central Montana through the remainder of the work week. Within this northwest flow subtle shortwaves, specifically today and Wednesday, will help to provide the "best coverage" for showers and storms as compared to Thursday and Friday when coverage will be more isolated to widely scattered in nature. With H700-H500 temperatures running anywhere 1 to 2.5 standard deviations below normal through Wednesday will support an environment conducive for cold air funnels, especially over the plains of Central and North Central Montana where surface heating will be the strongest in conjuction with the coldest air aloft. High temperatures will remain below normal through Wednesday, with temperatures moderating back above normal through the remainder of the work week. Transient upper level ridging then looks to overspread the Northern Rockies through the weekend and Monday before being flattened and replaced with predominately zonal flow. This aforementioned ridging will bring generally dry conditions to much of the Northern Rockies over the weekend; however, and isolated shower or storm can`t be ruled out over the mountains. Temperatures continue to moderate through the weekend, with well above normal temperatures expected as highs peak in the mid-70s to mid-80s. -Moldan - Forecast Confidence & Scenarios: Rainfall Today and Wednesday: In general, showers will remain light across the region through Tuesday afternoon. However, HREF guidance still shows the potential for some stronger storms to develop which could bring rainfall rates of 0.10" or greater west of the I-15 corridor (20-40%) with lower probabilities (10-30%) along the Island Ranges. On Wednesday, the HREF shifts its focus for heavier precipitation more towards the Island Ranges and particularly the Little Belts. Wednesday afternoon could see another round of isolated to scattered afternoon thunderstorms with some potential for some heavier downpours. At this time there is a low potential for severe weather for both Tuesday and Wednesday. However, an isolated stronger storm cannot be ruled out. Warmer Temperatures Next Week: The ECMWF EFI has been strongly hinting towards well above normal temperatures returning by Sunday and lasting through at least Monday. Currently the NBM has a 40-60% of highs exceeding 90 degrees along portions of north-central Montana including Havre, Shelby, Fort Benton, and Great Falls. Tuesday is expected to be slightly cooler however there is still a 10-30% chance for the same locations exceeding 90 degrees. The good news is, at this point in time, good overnight temperature recovery is expected with lows dipping into the 50s. Thus, the concerns for prolonged heat are minimal at this time. -thor && .AVIATION... 03/18Z TAF Period VFR conditions will prevail over the next 24 hours but rain showers, and even an isolated thunderstorm between 03/18Z and 04/06Z may briefly reduce VIS and/or CIGS to low-VFR. The highest coverage of showers and thunderstorms is expected over the plains of central and north-central Montana southwest of a line between KCTB and KLWT and northeast of the US Hwy 12 corridor. Mountain obscuration will be a concern through much of the TAF period, most notably along the Continental Divide. -Moldan/thor Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .HYDROLOGY... The Gallatin River, specifically at Logan, continues to run near or above Action Stage thanks to increased snowmelt and recent precipitation across the Madison and Gallatin Ranges in Southwest Montana. Latest river forecasts from the Missouri Basin River Forecast Center (MBRFC) keeps the Gallatin River below Minor Flood Stage at all forecast points, but users and those with interest along the river should be prepared for increased spring flows. - Moldan && .PRELIMINARY POINT TEMPS/POPS... GTF 40 67 42 73 / 50 30 10 10 CTB 38 66 39 74 / 60 20 10 0 HLN 42 70 44 76 / 40 30 10 10 BZN 37 67 39 71 / 40 10 10 10 WYS 29 62 30 66 / 30 10 10 20 DLN 37 64 37 69 / 20 0 0 10 HVR 39 70 42 77 / 50 20 10 10 LWT 37 62 41 68 / 40 50 20 20 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$ http://www.weather.gov/greatfalls