textproduct: Great Falls

KEY MESSAGES

- Gusty west winds develop this afternoon across north-central Montana with locally strong winds possible downslope of the island mountain ranges.

- Periods of gusty north winds along with some cooling and a few mountain snow showers are expected with additional weather disturbances moving across the area in the upcoming week.

- Much colder temperatures and the potential for snowfall returns next weekend.

DISCUSSION

/Issued 300 PM MST Sat Jan 17 2026/

- Meteorological Overview:

A highly meridional (N/S) upper level flow pattern remains in place through the upcoming week as the axis of a high amplitude ridge remains near or just off-shore of the west coast while large scale troughing gradually broadens across Canada, centered near Hudson Bay. This maintains an unusually strong northerly flow aloft across MT with multiple shortwave disturbances cascading southward across the region through the middle of next week. At the surface, clipper type systems associated with these shortwaves generally track east of the area from the Canadian Prairies through the Dakotas, accompanied by periods of stronger north winds but with limited moisture/precipitation potential.

Temperatures warm back above average today before the next disturbance moves in tonight, followed by cooler (seasonal) temperatures again on Sunday as surface high pressure builds in behind the disturbance. A belt of enhanced 40-60kt winds at 850-700MB tracks across eastern MT tonight through early Sunday morning with locally strong winds mainly affecting eastern portions of north- central MT, especially areas adjacent to the Sweet Grass Hills, Bears Paw, Judith and Snowy Ranges. Northerly upslope flow early Sunday may be able make use of the limited moisture to produce a few flurries or snow showers across the central/N-central MT mountains.

Similar weather is expected to accompany shortwave disturbances diving across the region through the middle of next week with some warming on Monday, followed by cooler temperatures again Tuesday and Wednesday. Slightly higher moisture and stronger cooling aloft will support a higher coverage of snow showers on Tuesday and Wednesday.

Longer range model ensembles support some retrogression of the ridge and enough broadening of the Canadian upper trough by the end of the upcoming week to bring a larger surge of cold air into the area, pushing temperatures below seasonal averages by next weekend. There is high degree of uncertainty still with details by then, but the potential exists for much colder temperatures and more widespread snowfall by next weekend. Hoenisch

- Forecast Confidence & Scenarios:

High Wind Tonight:

Hi-res models continue to suggest 65-75kt flow at 700mb. Even though the bulk of this wind event will occur at night, there is sufficiently high confidence that the stronger winds will be able to mix down to the surface to warrant upgrading most of the High Wind Watch to a High Wind Warning. The one portion of the watch that did not get upgraded was northern Blaine county including the cities of Chinook and Harlem.

Additionally, the timing of the warning was pushed out to late Sunday morning for southern Blaine and Fergus counties. The latest guidance from the HREF suggested that some of the stronger winds may last a bit longer than previously thought so additional time was added when the watch was upgraded to cover this potential.

For the eastern Toole and Liberty county portion of the warning, the main concerns will be in the areas immediately downslope of the Sweetgrass Hills.

Snow Squall Potential Tonight:

With the front moving through this evening, there is a potential for some light snow showers across the Hi-Line. WPC highlighted part of our area as having a low potential for snow squalls. The primary limiting factor for our portion of central Montana will be the lack of snow expected. Lower and upper-level moisture is overall lacking so while the dynamics would otherwise support snow squall development along the Hi-Line, without snow, the concern is just strong winds which is appropriately covered with the High Wind Warning in the Bears Paw and Fergus county. -thor

AVIATION

18/00Z TAF Period

Embedded shortwave within northwest flow aloft will spread lowering CIGS across North Central and Central Montana between 08-12z Sunday, with MVFR CIGS remaining along the northern and eastern slopes of the Island Ranges and Rocky Mountain Front. A cold front advancing south will also lead to a shift in surface winds to the northwest to north over the plains, with strong and gusty winds developing along and northeast of a KLWT to KCTB line. Mountain obscuration north of the I-90 corridor will occur beyond 08z Sunday and persist through the remainder of the TAF period. - Moldan

PRELIMINARY POINT TEMPS/POPS

GTF 27 35 18 42 / 10 10 0 0 CTB 23 31 13 41 / 0 10 0 0 HLN 23 36 17 37 / 10 10 0 0 BZN 19 35 12 36 / 0 10 0 0 WYS 4 29 -3 28 / 0 0 0 0 DLN 19 35 15 38 / 0 0 0 0 HVR 22 30 10 34 / 0 0 0 0 LWT 24 33 14 40 / 10 20 0 0

TFX WATCHES/WARNINGS/ADVISORIES

High Wind Warning until 7 AM MST Sunday for Eastern Toole and Liberty.

High Wind Warning until 11 AM MST Sunday for Bears Paw Mountains and Southern Blaine-Fergus County below 4500ft.