textproduct: Great Falls

KEY MESSAGES

- Warmer and drier Wednesday and Thursday. - Next weather system arrives Friday, bringing cooler temperatures along with some periods of rain/mountain snowfall. - Another weather system brings even cooler temperatures and more widespread precipitation to Montana, with more chances for mountain snowfall.

DISCUSSION

/Issued 527 AM MDT Wed Sep 9 2026/

- Meteorological Overview:

In the wake of a series of upper level systems earlier this week, a weak ridge embedded in northwesterly flow will bring a period of warmer but breezy weather to North Central Montana Wednesday and Thursday. This period of warmer weather will come to a quick end on Friday as a decaying upper level trough moves through Southern British Columbia and Alberta into Montana, which will bring cooler temperatures, along with some showers of rain and mountain snowfall as it pushes through. The cooler temperatures will linger behind this system, which will set up the next, stronger system to produce widespread precipitation with snow expected above 7000 feet, which would include some of the higher mountain passes. A brief period of warmer and drier weather is expected late Sunday and Monday before the unsettled pattern resumes by the middle of next week.

- Forecast Confidence & Scenarios:

Winds today and Thursday: Westerly, cross barrier flow will bring some gusty winds to North Central and Southwestern Montana Wednesday and Thursday. While winds are not expected to be strong enough to reach high wind criteria (58 mph for most, 75 mph along the Rocky Mountain Front), gusts to 35-50 mph will be possible across the area, especially on Thursday when winds will be strongest.

Mountain Snowfall this weekend: A strong upper level low will move into the Treasure State over the weekend, bringing well below average temperatures along with copious amounts of moisture. The cooler temperatures will bring snow levels down to 7000 feet above sea level, which will result in widespread mountain snowfall to areas above 7000 feet. Current forecasts keep snowfall amounts under 6 inches at the moment, but some of the highest terrain still have around a 10 percent chance of snowfall amounts over a foot over the weekend. Ludwig

AVIATION

09/18Z TAF Period

VFR conditions will dominate the region through the period. Winds will prevail out of the west-southwest this afternoon with gusts up to 25 KT to 30 KT throughout the region. There is a 60% probability for wind shear conditions at KCTB, KHVR, and KLWT tonight from 10/02Z to 10/11Z as boundary layer decoupling is possible for some areas with stronger synoptic forcing influence above. Thursday morning into afternoon will see gusty winds again as the mixed layer sets back up.

For KGTF: VFR conditions will persist with southwesterly winds gusting to 25 KT which will yield 15 KT crosswind exceedance at times until tonight after sunset. There is a 30% chance for wind shear conditions to set up overnight however boundary layer mixing is primarily expected to continue. A strong inversion setup with temperatures cooling below expected will be the difference for wind shear. - Akins

PRELIMINARY POINT TEMPS/POPS

GTF 54 81 47 63 / 0 0 70 60 CTB 50 71 41 56 / 0 0 60 60 HLN 49 83 52 69 / 0 0 60 30 BZN 44 83 47 72 / 0 0 10 20 WYS 29 71 35 70 / 0 0 0 0 DLN 41 81 44 74 / 0 0 0 0 HVR 49 81 43 65 / 0 0 30 50 LWT 49 83 45 62 / 0 0 60 70

TFX WATCHES/WARNINGS/ADVISORIES