textproduct: Great Falls

KEY MESSAGES

- Breezy to windy conditions will be present for much of the week, with the strongest and most widespread winds Tuesday night through Thursday.

- Mountain snow looks to be heaviest along the higher terrain along the Continental Divide.

- There will be a few opportunities for lower elevation precipitation, particularly over central and southwest Montana on Wednesday when scattered locally intense snow showers or squalls develop.

- Colder temperatures and periods of snow may return for the weekend, mostly for northern areas.

DISCUSSION

/Issued 218 PM MST Mon Feb 23 2026/

- Meteorological Overview:

Strengthening westerly flow aloft has all but completely eroded the stubborn Arctic airmass over the plains, with still some colder air holding out along the Milk River Valley. Temperatures should reach forecast highs by late this afternoon. The focus now shifts to stronger winds and mostly mountain snow going forward.

Moisture continues to stream towards the Continental Divide and is currently bringing areas of rain and snow to the higher terrain of the Rocky Mountian Front. A Pacific shortwave wave and attendant cold front will change the precipitation to all snow in these areas by later this afternoon and evening and the cold front will expand the snow to other mountain areas tonight into Tuesday. The temperatures aloft will be slightly over central and southwest MT while precipitation amounts remain light, so winter weather impacts should be negligible for most locales away from the divide. Lower elevations will generally remain dry, but a few scattered showers tonight into Tuesday seem plausible.

A stronger shortwave and Pacific cold front moves west to east across the state Tuesday night into Wednesday and will bring more widespread strong and gusty winds, at least a brief period locally heavy mountain snow, and lower elevation, scattered snow showers/squalls over central and southwest MT. The newer model data seems to be bringing the strongest winds aloft late Tuesday night into Wednesday morning, which doesn't align well peak diurnal mixing; however, there looks to be the presence of tight surface pressure gradients and mountain wave activity. This should keep the strongest surface winds mostly confined to the following areas; along the Continental Divide/plains west of I15, near the central MT highway 87/200 corridor, and over the more susceptible wind prone southwest valleys and mountain peaks.

There will also be some elevated instability with the cold front that will not only bring an opportunity for locally intense snow showers/squalls, but also may help transfer the 50 to 60 kts winds to the surface. Accumulating snow impacts will generally be confined to areas of higher terrain and may be briefly intense Wednesday morning given the combination of the convective snow and gusts over 50 mph.

On Thursday the jet stream begins to sag southward with 50 to 70 kt H700 winds settling over central/north-central MT. The peak of upper level winds looks to be more aligned with diurnal mixing while tight surface pressure gradients and mountain wave activity continues to be present through at least Friday morning. Winds along the Rocky Mountain Front will be most robust with gusts over 90 mph at times. With the lack of a more defined shortwave or cold front, it may be more difficult to get stronger winds in the more wind protected central and southwest valleys. Also, precipitation should temporarily dry out, even in the mountains.

Over 80% of ensembles bring a colder northwesterly flow aloft into the Northern Rockies heading into the weekend; however, disagreements remain on how far south the southern extent of the cold air will get. On Friday an Canadian cold front begins to move southward over the plains, although it may lose momentum and stall out over the central ranges or even retreat northward before making a deeper southward push later in the weekend into early next week. Overall, there is an expectation for return to near to below average temperatures, coldest for northern areas. Snowfall positioning and accumulations will ultimately depend where the boundary sets up and the timing of subtle shortwave disturbances within the aforementioned northwesterly flow aloft. - RCG

- Forecast Confidence & Scenarios:

Windy conditions through Friday morning, strongest and most widespread widespread Tuesday night through early Friday...

Despite stronger westerly flow aloft this afternoon, momentum transfer to the surface hasn't been impressive over the plains thus far. This is likely being slowed by a thin layer of snow on the ground. None the less there still may be a few gusts approaching 50 mph later in the afternoon, mostly over the plains west of I15 and along the central MT highway 87/200 corridor.

The winds will be much stronger and more widespread Tuesday night through early Friday. The first wave will driven by a shortwave and attendant cold frontal passage late Tuesday night into Wednesday. Probabilities are now running over 80% for gusts over 80 mph along the Rocky Mountain Front and adjacent high plains while many central and southwestern areas see the chance for 55 mph gusts increase to over 70%. Locations along the Continental Divide, including the Helena area, are now approaching the 50% chance mark for 70 mph +gusts. The inherited watches were generally left untouched, but I did add the Madison and Beaverhead valleys due to the cold front increasing the risks for the stronger gusts reaching the surface. Impacts with this first event will be felt greatest for areas along the Continental Divide were the chances for 70 mph + gusts will be greatest. Should these magnitude of winds occur in the Helena area or any other urban area, then tree damage and power outages can't be ruled out. Along the Rocky Mountain Front, dangerous travel for high profile or light weight vehicles will be the primary impact.

Another round of strong winds move in Wednesday night through early Friday. More robust mountain wave activity looks to bring even stronger winds to areas on the lee side of terrain, especially along the Rocky Mountain Front were gusts may exceed the 90 to 100 mph range. Other areas that will be susceptible to 70 mph gusts will be the central MT highway 200 corridor and over the Bears Paw Mountains. A high wind watch was issued for these areas, but I did leave out the bigger urban centers of the southwest due to more dependence on mountain wave activity to bring to higher end winds to these areas. Impacts look to be most severe along the Rocky Mountain Front were dangerous travel for high profile or light weight vehicles is expected once again amid 80 to 100 mph gusts.

Mostly mountain snow through mid-week...

Snow looks to be heaviest along the Continental Divide through Wednesday. Winter weather advisories are now posted for most of the divide through Tuesday morning, with 3 to 7 inches of snow at pass level, particularly for Marias and the Chief Joseph Pass areas. An advisory was also posted for the King's Pass area with totals nearing 4 inches through Tuesday morning. Additional advisories will be considered for Tuesday night into Wednesday.

Another concern is for snow showers/squalls developing over central and southwest MT on Wednesday. This convective activity will be accompanied by the aforementioned strong wind gusts. Newer model guidance has backed off some in regards to colder air aloft, but there's still sufficient instability to cause at least brief wind and snow impacts, especially over and near mountain passes Wednesday morning. - RCG

AVIATION

24/00Z TAF Period

An abundance of Pacific moisture streaming northeastward and over the Northern Rockies will lead to lowering CIGS and increasing chances for rain/snow over some terminals, mainly along and south of a KGTF to KLWT line, for much of the 2400/2500 TAF period. Mountain obscuration will continue to increase through 06z Tuesday as the aforementioned moisture spills east of the Continental Divide, with CIGS lowering from VFR to MVFR/low-VFR through 06-09z Tuesday. In addition to increasing low to mid-level cloud cover, strong and gusty winds will continue for much of the next 24 hours, with even stronger winds arriving for the middle to later part of the work week. - Moldan

PRELIMINARY POINT TEMPS/POPS

GTF 31 47 30 49 / 30 20 30 10 CTB 23 43 26 43 / 20 0 10 0 HLN 32 47 30 44 / 50 60 70 30 BZN 33 48 30 46 / 20 60 60 40 WYS 25 36 27 38 / 50 90 90 80 DLN 32 48 32 44 / 20 50 40 30 HVR 20 40 21 48 / 10 0 30 10 LWT 27 40 27 44 / 60 50 60 20

TFX WATCHES/WARNINGS/ADVISORIES

Winter Weather Advisory until 11 AM MST Tuesday for East Glacier Park Region-Southern Rocky Mountain Front-Upper Blackfoot and MacDonald Pass.

High Wind Watch from late Tuesday night through Friday morning for East Glacier Park Region-Eastern Glacier, Western Toole, and Central Pondera-Northern High Plains-Southern High Plains- Southern Rocky Mountain Front.

High Wind Watch from Wednesday evening through Friday morning for Bears Paw Mountains and Southern Blaine-Western and Central Chouteau County.

Winter Weather Advisory from midnight tonight to 11 AM MST Tuesday for Little Belt and Highwood Mountains.

High Wind Watch from late Tuesday night through Friday morning for Big Belt, Bridger and Castle Mountains-Cascade County below 5000ft-Gates of the Mountains-Judith Basin County and Judith Gap- Little Belt and Highwood Mountains-Upper Blackfoot and MacDonald Pass.

High Wind Watch from late Tuesday night through Wednesday evening for Beaverhead and Western Madison below 6000ft-Canyon Ferry Area-Elkhorn and Boulder Mountains-Gallatin Valley-Helena Valley-Madison River Valley-Meagher County Valleys-Missouri Headwaters.

Winter Weather Advisory until 11 AM MST Tuesday for Northwest Beaverhead County.