textproduct: Great Falls

KEY MESSAGES

- Gusty west winds develop today across north-central Montana and shift to the north tonight with locally strong winds possible across eastern portions of north-central Montana.

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

- A turn to much colder temperatures and increased risk for snowfall may develop by next weekend.

UPDATE

No major changes were made to the going forecast. Regarding the High Wind Watch, confidence is still pretty marginal for high winds. The best chances are in the Bears Paw and locations immediately downwind of the Snowies and Judiths in eastern Fergus county. At this point, we will wait for more model data to arrive to determine if the threat level reaches warning criteria for this evening. -thor

DISCUSSION

/Issued 412 AM 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:

The High Wind Watch was adjusted to start this evening and expanded to Fergus county. Overnight timing of the strongest NNW flow aloft may keep the potential for strong winds more isolated to areas closest to Island Ranges and probabilistic model guidance remains at or below 50% for gusts in excess of 50kts. Still, this may be overcome by strong pressure rises and cold advection with latest model data supporting the highest risk for strong wind gusts across eastern portions of Fergus County. Hoenisch

AVIATION

17/12Z TAF Period

Gusty west surface winds develop at north-central MT terminals today and shift to the northwest this evening. Flow aloft remains from the north to northwest and increases later today and tonight, supporting some instances of low level winds shear and mountain wave turbulence, primarily across north-central MT. VFR conditions prevail with just some areas of mid-high level clouds through this evening. Mid-level clouds increase late tonight with some lower level clouds and mountain obscuration possible near the central MT mountains Sunday morning. Hoenisch

PRELIMINARY POINT TEMPS/POPS

GTF 48 27 35 18 / 0 10 10 0 CTB 48 23 31 13 / 0 0 0 0 HLN 42 23 36 18 / 0 0 10 0 BZN 40 18 36 14 / 0 0 0 0 WYS 30 3 29 -2 / 0 0 0 0 DLN 43 19 36 16 / 0 0 0 0 HVR 42 22 31 11 / 0 0 0 0 LWT 49 24 33 14 / 0 0 20 0

TFX WATCHES/WARNINGS/ADVISORIES

High Wind Watch from 6 PM MST this evening through late tonight for Bears Paw Mountains and Southern Blaine-Eastern Toole and Liberty-Fergus County below 4500ft-Northern Blaine County.