textproduct: Great Falls

KEY MESSAGES

- Snow continues today with areas of heavy snow and gusty winds on Saturday. - Gusty winds return next week. - Warmth returns to the area as a heatwave builds across the Southwestern US.

UPDATE

/Issued 857 PM MDT Fri Mar 13 2026/

Moist westerly flow aloft overrunning the cool, moist low level air mass over central/north-central MT will maintain periods of snow over central/north-central MT. Pops, snow totals, and temperatures were nudged towards current trends. The main adjustment was to better align forecast parameters with Satruday's cold frontal passage. Otherwise, the previous forecast package remains on track. - RCG

DISCUSSION

/Issued 857 PM MDT Fri Mar 13 2026/

- Meteorological Overview:

A dynamic atmospheric river continues to impact the area today and tomorrow, bringing widespread snow to North Central and Central Montana this afternoon, with some gusty winds across Southwestern Montana. This atmospheric river will continue to impact the area through the day on Saturday, though some enhancement in snowfall rates and winds are expected as a shortwave trough swings through the Northern Rockies. Expect snowfall rates to increase tonight, with winds across SW Montana strengthening tomorrow afternoon.

Snow will slowly taper off Saturday evening as high pressure builds near the surface and the end of the atmospheric river moves to our east. Once this happens, we will have one day of cooler temperatures before temperatures begin to rapidly rise through the remainder of the week as unusually strong upper level ridging builds in across the western US. With the top of the ridge being over or just north of Montana, it will be another windy week, with multiple days of strong wind gusts, especially along the Rocky Mountain Front.

- Forecast Confidence & Scenarios:

Snow and wind through Saturday: Snow will continue to fall across a large portion of North Central and Central Montana through the remainder of the day today and into tonight, with the heaviest snow focused along and south of a line from Treat Falls to Lewistown, and north of a Helena to White Sulphur Springs line. This snow will begin to intensify later tonight and Saturday as the aforementioned upper level trough pushes into eastern Washington and Northern Idaho, resulting in more favorable atmospheric dynamics/lift ahead of the trough. This will result in increasing snowfall rates across Central and North Central Montana, along with a temporary northward shift in the axis of heaviest snowfall during the mid to late morning hours. However, as the trough continues on its eastward path, we will see some instability across Southwestern Montana that may result in some gusty snow showers/squalls in addition to some gusty winds mixing to the surface from daytime heating. Further north, the passage of the upper level trough will pull down a high pressure system from Canada, which could result in a barrier jet to form along the Rocky Mountain Front and cause some gusty winds for a time, which may result in localized blowing snow along and west of the I 15 corridor north of Cascade/Great Falls.

Winds next week: The upper level ridge that will dominate the weather across the Southwestern US will build early next week, which will push the jet stream back over our area for at least the middle of next week. With the jet stream overhead, northwesterly flow aloft will result in gusty winds at the surface, especially along the Rocky Mountain Front, and possibly just east of the Highwood, Bears Paw, Little Belt, Judith, and Snowy mountain ranges. The highest risk for strong winds will look to be around Tuesday, when the axis of the upper level ridge will pivot overhead and winds become more westerly. Winds are not currently expected to be as strong as the past few wind events, but the accumulated wind stress from past wind events this year could still result in some damage. Ludwig

AVIATION

14/06z TAF Period

A steady stream of Pacific moisture across the Rockies will maintain widespread light snow and IFR conditions across most north-central MT terminals to as far south as KHLN through Saturday morning. Mainly VFR conditions persist across SW MT terminals overnight but ceilings gradually lower as moisture increases by Saturday morning. Strong westerly flow aloft across southwest MT will produce areas of low-level wind shear until westerly winds mix back to the surface there Saturday morning. A cold front pushes through the region Saturday bringing a period of enhanced snowfall rates to north-central MT terminals followed by a shift to gusty north winds which may create some additional visibility reductions in blowing snow for a period Saturday afternoon. Locally intense (rain changing to snow) showers accompanied by strong winds gusts may occur with the frontal passage across SW MT terminals between 15z and 20z Saturday. Hoenisch

PRELIMINARY POINT TEMPS/POPS

GTF 25 31 8 30 / 90 90 80 10 CTB 17 25 -2 26 / 70 90 30 0 HLN 29 36 12 35 / 90 90 90 10 BZN 38 50 13 36 / 50 80 80 10 WYS 30 43 5 30 / 50 90 70 20 DLN 38 49 17 38 / 30 70 40 0 HVR 20 30 5 27 / 50 90 50 0 LWT 21 34 4 27 / 100 100 80 20

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.

High Wind Warning from noon to 9 PM MDT Saturday for Beaverhead and Western Madison below 6000ft-Big Belt, Bridger and Castle Mountains-Canyon Ferry Area-Elkhorn and Boulder Mountains- Gallatin Valley-Gallatin and Madison County Mountains and Centennial Mountains-Madison River Valley-Missouri Headwaters- Northwest Beaverhead County-Ruby Mountains and Southern Beaverhead Mountains.