textproduct: Great Falls

KEY MESSAGES

- Periods of moderate to heavy mountain and lower elevation snow continues on and off through Saturday.

- Gusty winds expected in Southwest Montana Friday and Saturday.

- Warmer temperatures move in next week, with light precipitation in mainly the mountains.

UPDATE

/Issued 351 AM MDT Fri Mar 13 2026/ 345 AM...Updated morning forecast is out. Main adjustment was to increase pops over North Central MT where it is snowing. Expect light snow to affect much of North Central MT through this morning, with gradual snow accumulations through the morning hours. Brusda

DISCUSSION

/Issued 351 AM MDT Fri Mar 13 2026/

- Meteorological Overview:

Pacific moisture continues to stream into the region. This moisture overriding the colder airmass will continue to fill in snow across North-Central MT tonight. Widespread snow is expected through Friday morning. A mid-level convergence zone across the MT Highway 200 corridor, will bring periods of moderate to heavy snow along that strip through the night and into Friday morning. The surface front will continue to stall out along the Missouri Headwaters region, with the mid-level front wavering a bit north- south of the MT highway 200 corridor through Saturday. This will bring periods of widespread snow for places mostly north of I-90/Missouri Headwaters through Saturday, with moderate and heavy snow more concentrated across Central/North Central MT. Orographically enhanced snow continues along the Continental Divide and mountains through Saturday. The higher moisture content will help aid in continuing moderate to heavy snow at mountain passes.

Most of the mountain snow in Southwest MT will be above pass level due to the warmer conditions south of the front. Though overnight temperatures dropping close or below freezing will allow for some light snow to develop. The main concern in Southwest MT will be gusty winds Friday and Saturday. Friday, decent mid-level winds will try to mix down to the surface in the afternoon. Saturday looks to be mostly pressure gradient driven as that low finally pushes southeast out of the region. Convective showers look to develop as this system tries to push in colder air Saturday afternoon and evening into Southwest MT, with a slight chance for a few locally heavy snow showers/snow squalls.

Heading into next week, we transition to a northwest flow aloft pattern with the ridge building in the Western U.S. A few disturbances will moves through the area throughout the week, bringing light precipitation and windy conditions. Another strong mid level jet moves into the Rocky Mountain Front and Central MT late Monday and Tuesday, which could potentially bring another round of strong winds. Warm temperatures move in by mid-week. Overnight cold temperatures in the low to mid 30s should limit any flooding concerns due to snow melt.

- Forecast Confidence & Scenarios:

Snow Through Saturday:

High confidence remains in heavy snowfall developing along the Continental Divide and Central MT mountains overnight tonight, continuing on and off through Saturday afternoon. Current mid level frontogenesis will continue moderate to heavy snow bands in Fergus and Judith Basin Counties at times. Snow filling in across North-Central MT tonight will bring some moderate to heavy snow banding, but it will be more localized tonight. Better chances for moderate to heavy snowfall at lower elevations across North- Central MT will be Friday night to Saturday. Any wet pavements from this evening will freeze and become slick overnight, which will affect the Friday morning and evening commutes regardless in how much snow falls overnight.

One area of uncertainty in snowfall amounts is the Hi-line/Chouteau County. So far they are on the cutoff line where better snow banding develops Friday night into Saturday. Depending on where the convergence zone sets up, they could get more or less than forecasted. We will have to watch for any upgrades to the Winter Weather Advisory, especially Chouteau County. Saturday, we will have to watch for the slight potential in the development of snow squalls, especially in Southwest MT. A front bringing in colder air aloft looks to drop surface wet bulb temperatures below freezing, so dynamic cooling could help push temperatures to freezing and develop moderate to heavy snow showers. -Wilson

AVIATION

13/18z TAF Period

North-Central Montana (KCTB, KHVR): The heaviest snow will be found along the Rocky Mountain Front with KCTB expected to be right along the border of where heavier snow is located. The first couple hours will maintain VFR conditions before low clouds move in towards the mid-afternoon with increasing chances for snow that will last through the rest of the TAF period. The threat for LIFR/VLIFR conditions will start after 14/00Z and last through the rest of the period. Mountain obscuration will remain a concern over the next 24 hours.

Further east along the Hi-Line towards KHVR, snow is expected to lift by 13/20Z with a temporary break in the snow before another round of snow arrives after 14/06Z. Through the rest of the period a mix of IFR/LIFR conditions will persist at KHVR.

Central Montana (KGTF, KLWT, KHLN): Snow will continue on and off through the rest of today with a more potent push of snow expected Saturday morning and afternoon. Both KGTF and KLWT will likely fluctuate between IFR and LIFR conditions through most of the period with the highest chances for LIFR/VLIFR after 14/06Z.

KHLN will maintain MVFR through the start of the period and dip down into IFR overnight with the next push of moisture. Precipitation type will generally be a rain/snow mix as temperatures will linger right above freezing through the period. The best chance for snow will be between 14/09Z and 14/18Z. Mountain obscuration will remain a concern through the next 24 hours.

Southwest Montana (KBZN, KEKS): Mountain snow will continue through the period with mountain obscuration remaining a concern over the next 30 hours. Gusty winds are expected today and tomorrow afternoon across Southwest Montana with instances of LLWS possible, particularly at KEKS. Generally VFR conditions will persist except around rain/snow showers where MVFR/IFR conditions are possible. -thor

PRELIMINARY POINT TEMPS/POPS

GTF 34 25 31 9 / 100 90 100 80 CTB 29 18 24 -2 / 100 80 90 30 HLN 44 31 42 13 / 100 90 90 90 BZN 55 36 49 13 / 70 50 80 80 WYS 45 30 42 7 / 50 50 90 70 DLN 56 38 49 17 / 30 30 70 40 HVR 35 20 29 6 / 50 70 90 50 LWT 32 21 34 5 / 100 100 100 80

TFX WATCHES/WARNINGS/ADVISORIES

Winter Storm Warning until 6 PM MDT Saturday for Big Belt, Bridger and Castle Mountains-Cascade County below 5000ft-East Glacier Park Region-Eastern Pondera and Eastern Teton-Elkhorn and Boulder Mountains-Fergus County below 4500ft-Gates of the Mountains-Helena Valley-Judith Basin County and Judith Gap- Little Belt and Highwood Mountains-Meagher County Valleys- Northern High Plains-Northwest Beaverhead County-Snowy and Judith Mountains-Southern High Plains-Southern Rocky Mountain Front-Upper Blackfoot and MacDonald Pass.

Winter Weather Advisory until 6 PM MDT Saturday for Bears Paw Mountains and Southern Blaine-Eastern Glacier, Western Toole, and Central Pondera-Eastern Toole and Liberty-Western and Central Chouteau County.