textproduct: Great Falls

KEY MESSAGES

- Widespread snowfall will begin this evening and continue through Saturday morning with the greatest impacts across North-central Montana on Friday.

- Coldest temperatures of the winter so far will move into the area Friday afternoon through Monday morning with Saturday through Sunday morning being the coldest.

- Another system will bring widespread snowfall to the area Tuesday through Wednesday.

UPDATE

/Issued 809 PM MST Thu Nov 27 2025/ Update forecast is out for this evening. Overrunning light rain/snow is moving through Central/North Central MT this evening. Some freezing rain reported just south of Great Falls, while light rain falling around Helena. Snow falling from about Great Falls northward. Web cams in the Conrad/Cut Bank area show about 1/2 to 1 inch of snowfall so far this evening. The precipitation is moving into the Havre/Lewistown areas as of 8 PM.

Overall the storm is on track. No changes to current statements at this time. The main concern is the NAM model is about 3 hours slower with the precip arriving in Southwest MT on Friday morning. This could have more of an impact if the brunt of the snow hits late morning/early afternoon. Thus the potential for snow squalls along/south of I-90 from Butte to Bozeman has gone up a bit.

Overall, do expect cold air to move into the CWA from north to south throughout the day. Wet roadways will freeze over, as this air mass is very cold. North winds gusting near 40 mph at times from Cut Bank to Helena will create near whiteout conditions at times in open areas. By Friday evening, air temperatures will be around 15 above in Helena, near 10 above in Great Falls, and in the single digits in the Cut Bank area. Wind chills will make it feel much colder. These conditions could create impacts for outdoor events planned for on Friday evening. Even though all areas might not receive a significant snowfall with this event, the combination of all the weather conditions will make for a difficult day to be outside. Brusda

DISCUSSION

/Issued 809 PM MST Thu Nov 27 2025/

- Meteorological Overview:

This afternoon there is an an upper-level trough approaching North- central, Central, and Southwestern Montana. There is also a warm front moving north through Central and North-central Montana. This will override the cold surface air and bring snow to North-central Montana this afternoon and evening. Tonight into early tomorrow morning a cold front will move through North-central Montana. This will bring another round of snow to North-central Montana early Friday morning through the day on Friday. Early Friday morning through the day on Friday there will be gusty winds which will lead to blowing and drifting snow. Friday morning the front will move through Central Montana and bring snowfall to that area. The front progression will slow down as it reaches Southwestern Montana, but it will still bring a light round of snow to Southwestern Montana. Friday afternoon along and south of I-90 combined with the frontal passage there is the potential for snow squalls.

On Saturday the upper-level trough will remain over North-central, Central, and Southwestern Montana. Snow will linger through early Saturday morning with cold temperatures across North-central, Central, and Southwestern Montana. On Sunday the upper-level trough remains over North-central, Central, and Southwestern Montana. This will bring another day of cold temperatures to the area with the coldest temperatures of the year expected Saturday through Sunday morning. On Monday an upper-level ridge builds in over North- central, Central, and Southwestern Montana. This will allow temperatures to warm up with mostly dry weather. On Tuesday and Wednesday an upper-level trough will move over the area and bring another round of snow to North-central, Central, and Southwestern Montana. IG

- Forecast Confidence & Scenarios:

On Friday there is greater than an 80% chance for wind gusts of 40 mph or greater across the Rocky Mountain Front and plains west of I- 15. On Friday across much of the rest of North-central, Central, and Southwestern Montana there is greater than a 60% chance for wind gusts of 30 mph or greater. Across much of North-central Montana there is greater than a 50% chance for 6 inches of snowfall or greater from tonight through early Saturday morning. This combined with the wind gusts led to Winter Storm Warnings being issued across all of North-central Montana. Across the Helena, Gallatin, and Madison River Valley there is a 30 - 60% chance for two inches of snow or greater tonight through early Saturday morning. As a result Winter Weather Advisories are in effect for those areas. For details see the TFX WATCHES/WARNINGS/ADVISORIES section below.

With the passage of the cold front combined with a little instability Friday afternoon along and south of I-90 there is medium confidence in there being snow squalls Friday afternoon. Saturday morning across the Hi-Line, Golden Triangle Region (triangular area from Cut Bank to Havre to Great Falls), and Gallatin valley there is greater than a 60% chance for subzero temperatures. Sunday morning there is greater than a 50% chance for subzero temperatures across all of North-central Montana. Sunday morning across the Milk River Valley there is greater than a 50% chance for temperatures of 10 below zero or lower. Monday morning across the Milk River Valley there is greater than a 60% chance for subzero lows. On Saturday there is greater than a 50% chance for highs of 15 degrees or lower across much of North- central Montana. On Sunday there is greater than a 50% chance for highs or 15 degrees or colder across North-central Montana east of I-15. IG

AVIATION

28/06Z TAF Period

The cold front will continue to make its way south across the region, shifting winds to the north and bringing periods of enhanced snowfall. Periods of blowing snow and even whiteout conditions are possible at KCTB, KHVR, and KGTF. Snow and lower CIGs will spread into southwest Montana by 28/15Z. Mountain obscuration across north-central, central, and southwest Montana will remain a concern through the period. -thor

PRELIMINARY POINT TEMPS/POPS

GTF 18 18 -2 14 / 80 90 40 0 CTB 11 14 -12 10 / 100 90 20 0 HLN 19 22 3 21 / 70 100 30 0 BZN 24 28 0 20 / 40 90 40 0 WYS 18 32 -6 21 / 10 80 60 0 DLN 28 39 4 24 / 10 70 20 0 HVR 13 20 -10 8 / 90 90 70 0 LWT 15 20 -2 17 / 90 90 70 10

TFX WATCHES/WARNINGS/ADVISORIES

Winter Storm Warning until 11 PM MST Friday for Cascade County below 5000ft-Eastern Pondera and Eastern Teton-Eastern Toole and Liberty-Southern High Plains-Southern Rocky Mountain Front- Western and Central Chouteau County.

Winter Storm Warning until 5 AM MST Saturday for Bears Paw Mountains and Southern Blaine-Fergus County below 4500ft-Hill County-Northern Blaine County.

Winter Weather Advisory until 5 AM MST Saturday for Big Belt, Bridger and Castle Mountains-Elkhorn and Boulder Mountains- Gallatin Valley-Gates of the Mountains-Helena Valley-Judith Basin County and Judith Gap-Little Belt and Highwood Mountains- Madison River Valley-Snowy and Judith Mountains.

Winter Storm Warning until 5 PM MST Friday for East Glacier Park Region-Eastern Glacier, Western Toole, and Central Pondera- Northern High Plains.

Winter Weather Advisory until 5 PM MST Friday for Upper Blackfoot and MacDonald Pass.