textproduct: Great Falls

KEY MESSAGES

- Mild and dry conditions will continue through Thursday.

- Widespread precipitation returns late Thursday into Friday with cooler temperatures lasting through the weekend.

DISCUSSION

/Issued 521 PM MDT Wed Oct 21 2026/

- Meteorological Overview:

Today over Southwestern Montana there remains Southwest flow aloft with weak zonal flow (west-east) over North-central, and Central Montana. Due to slightly stronger warm air advection today temperatures will rebound to above seasonal averages. Across North- central and Central Montana it will be dry with a low chance for showers across Southwestern Montana today. See the Forecast Confidence & Scenarios Section for details. On Thursday there remains southerly flow aloft and an upper-level trough associated with a Pacific Cold front begins to move over North-central, Central, and Southwestern Montana by Thursday evening. This will allow temperatures to remain above seasonal averages with mostly dry weather until Thursday evening. Thursday evening into Friday morning precipitation will gradually spread over North-central, Central, and Southwestern Montana.

On Friday the upper-level trough merges with a shortwave trough moving south from Canada. This combined with the cold front that moved through will bring widespread precipitation and cooler temperatures (below seasonal averages) to the area. Due to the cold front that moved through Thursday evening into Friday morning snow-levels will lower and the precipitation that falls in mountain areas on Friday will transition from rain to snow by Friday evening. On Friday there is an increasing pressure gradient and strong low-level and mid-level winds. This will bring windy conditions to North-central Montana on Friday. On Saturday an upper-level ridge begins to build in over North-central, Central, and Southwestern Montana. This will allow the area to dry out with cool temperatures lingering.

On Sunday the upper-level ridge remains over North-central, Central, and Southwestern Montana. This will keep dry and cool (below seasonal averages) weather for the area on Sunday. Monday through Tuesday an upper-level trough moves over North-central, Central, and Southwestern Montana. This will bring cooler temperatures and widespread precipitation to the area on Monday and Tuesday. -IG

- Forecast Confidence & Scenarios:

For total liquid precipitation Thursday night through Friday night there is greater than an 80% chance for one half inch of liquid precipitation or greater along and south of the Montana Highway 200/US Highway 87 Corridor between Great Falls and Lewistown. For total liquid precipitation Thursday night through Friday night there is a 30 - 60% chance for one half inch of liquid precipitation across North-central Montana north of the Montana Highway 200/US Highway 87 Corridor between Great Falls and Lewistown. For total liquid precipitation Thursday night through Friday night there is a 60 - 90% chance for one inch of liquid precipitation or greater across Central and Southwestern Montana.

Across most of the mountains of North-central, Central, and Southwestern Montana there is greater than a 60% chance for 2 inches of snow or greater from Thursday night through Friday night. Thursday night through Friday night there is a 50 - 80% chance for 4 inches of snow or greater across the Madison and Gallatin ranges and the Little Belts. Friday afternoon into early Saturday morning there is a high chance that at least some lower- elevation locations across North-central, Central, and Southwestern Montana will see a few flakes of snow. There is a bit of uncertainty regarding how low snow levels will get which would influence how much snow will be observed at lower elevations. Right now there are some models suggesting 1 to 3 inches in Great Falls but there is a lot of uncertainty given how warm this system is compared to what would be more productive for higher snowfall amounts. -IG/thor

AVIATION

22/06z TAF Period

VFR conditions will prevail through the TAF period. Light to breezy winds will continues across all terminals, peaking during peak heating hours and waning through the nights. Cloud cover should be limited, but increased through the TAF period with the approach of the next storm system. Terminal KWYS will have a brief period of increased cloud cover 22/09z to 22/16z with the potential for a few low- level clouds to develop down to 3kft. -JR

PRELIMINARY POINT TEMPS/POPS

GTF 73 45 72 44 / 0 0 0 30 CTB 68 40 69 37 / 0 0 0 60 HLN 68 38 70 43 / 0 0 0 40 BZN 67 38 70 40 / 0 0 0 30 WYS 61 30 62 33 / 20 0 10 80 DLN 66 38 66 42 / 10 0 10 80 HVR 69 38 73 41 / 0 0 0 20 LWT 71 45 74 45 / 0 0 0 20

TFX WATCHES/WARNINGS/ADVISORIES

None.