textproduct: Great Falls

KEY MESSAGES

- A period of snow with embedded locally intense snow showers will move through the area Tuesday, bringing a return to winter driving conditions.

- Gusty north to northwest winds with create areas of blowing and drifting snow primarily across portions of north-central Montana Tuesday afternoon and evening.

- A much colder airmass sliding south from Canada will bring temperatures as low as the single digits above and below zero to portions of north-central Montana Tuesday night through Wednesday night.

UPDATE

/Issued 919 AM MST Tue Feb 17 2026/

9:15 AM : Late morning update has been published, with the primary changes being to add Eastern Pondera/Teton Counties and Cascade County below 5000ft to the Winter Weather Advisory given expected snowfall amounts of between 1-3 inches across these areas combined with strong and gusty northwest winds leading to areas of blowing/drifting snow. - Moldan

4:57 AM : Things appear to still be on track from last night's forecast package. As this system pushes into the area, we continue to be concerned about snow squalls, as strong dynamics with the arrival of the system are likely to result in a rapid onset of moderate to heavy snow, along with some gusty winds. Roads may quickly become snow covered and slick, even though road surfaces are still relatively warm. If anything, this could make the situation worse, as snow rapidly melts and then may refreeze as the snow continues to fall. Ludwig

DISCUSSION

/Issued 919 AM MST Tue Feb 17 2026/

- Meteorological Overview:

A major weather pattern change remains on track for today as a deepening upper level trough along the west coast shifts inland with an embedded wave, currently moving into CA, lifting out across the Northern Rockies and MT on Tuesday. Deepening surface low pressure tracks across SW MT Tuesday morning beneath the negatively tilted wave, while Pacific moisture is focused along an eastward moving cold font associated with the leading edge of strong cooling aloft immediately behind the surface low. Snow begins late tonight near the ID/WY border as Pacific moisture begins to stream into the region with an area of more widespread precipitation developing further west along the continental divide by Tuesday morning, which then lifts across central/north-central late Tuesday morning through the afternoon with the passage of the surface low and upper level wave. Gusty south winds across southwest MT will intensify tonight with most of the area seeing a shift to gusty west winds as the frontal system and surface low move east across the area Tuesday afternoon.

A much colder airmass spreads south across the area Tuesday night through Wednesday, cooling temperatures to well below seasonal averages with the most drastic cooling occurring across north-central MT. A weaker wave of Pacific moisture moves north into the area Wednesday through Wednesday night, spreading mainly light snow with minor accumulation as far north as central MT with up to a few inches of snow accumulation possible through that period across the southwest MT mountains. Upper level troughing remains in place through Friday though gradually weakens, maintaining cooler than average temperatures with some moderation. Upper level ridging looks to redevelop across the interior western US this weekend with temperatures continuing to moderate, but some uncertainty in how much moderation occurs across north-central MT with surface high pressure still centered north of the area and no indication of lee-side surface trough development. Hoenisch

- Forecast Confidence & Scenarios:

Snowband and Snow Squall Potential Today:

There is very high confidence in the models that a snow band will set up along the Continental Divide early Tuesday morning and propagate towards the east through the afternoon hours. Right now, the best approximate timing for this snowband arriving is as follows:

- Cut Bank and Great Falls: 6-9AM - Inverness to Fort Benton: 9AM-12PM - Havre to Hays: 12-3PM

One wild card is how fast the snowband will move across north- central Montana. Most of the models are pretty good at moving it through quickly which will reduce overall impacts and snowfall amounts. The concern is that if this snowband propagates slower than currently expected, the level of impacts may start to increase fairly quickly.

Based on the current model guidance and the dynamics of how this system is expected to move through, the current Winter Weather Advisory remains sufficient. Some lower elevation locations of central and north-central Montana have been left out of a Winter Weather Advisory for now because the majority of the snowfall is expected to occur within the snowband and thus the timing is too short for an advisory and better messaging will be provided by short fused products as the event unfolds. But this will be monitored very closely as deviations in the track and timing of the snowband could potentially have significant impacts.

Additionally there is a chance for snow squalls across southwest Montana this morning, primarily before noon as the front moves through. The main impact would be to the Tuesday morning commute along I-90. But because there is more uncertainty in how the snow squall potential will pan out in southwest Montana as opposed to north-central Montana, no additional Winter Weather Advisories. Similar to the unwarned counties in north-central Montana, any snow squall or snowband that develops will be handled accordingly with short-fused products.

Blizzard Conditions Along the Hi-Line:

The first wave of snow and reduction in visibility arrives with the snowband which is currently expected to happen in the early to mid afternoon. The second wave of snow and visibility reduction comes a little later in the afternoon as the wave moves further east and wrap around moisture starts to funnel in across the Hi-Line into northeastern Montana. While the snowband is expected to be relatively short-lived, the wrap around moisture could prove more of an issue for longer duration visibility reductions.

The main limiting factor is the snow amounts. Right now there is only marginal confidence in at least 2 inches of snow falling across the Hi-Line east of Havre to the Phillips county border. With winds potentially gusting up to 60 mph, even an inch of falling snow can cause temporary reductions in visibility. But the question becomes will the visibility be reduced down to a quarter of a mile for at least three hours to sustain full blizzard conditions. That is where confidence drops off significantly. Periods of blizzard conditions are very likely. Sustained blizzard conditions are a lot less likely in our portion of the Hi-Line.

All that being said, visibilities less than one mile are still expected to last anywhere from 3 to 5 hours, which combined with icy conditions due to the sudden drop in temperature as the cold front moves through and changes the rain over to snow, will likely cause sustained severe driving conditions. So to account for that threat, the advisory was upgrade to a Winter Storm Warning for northern Blaine county. The probabilities drop off enough by Havre that the decision was, for now, to leave them out of the upgrade. But hazardous driving conditions are still possible across most of US-2 through tonight. -thor

AVIATION

17/18Z TAF Period

Areas of moderate to heavy snow continue northeastward across the region into the afternoon, largely diminishing by the evening. Gusty west to northwest winds will persist in most areas through the early evening as well, resulting in some patchy instances of blowing snow. Low clouds are likely to linger in spots tonight before another period of snow develops Wednesday morning. -AM

PRELIMINARY POINT TEMPS/POPS

GTF 38 -8 0 -8 / 100 20 60 50 CTB 28 -13 -7 -17 / 100 10 30 10 HLN 39 0 8 -4 / 100 20 70 60 BZN 42 12 18 0 / 70 20 60 70 WYS 32 9 27 -2 / 100 70 90 90 DLN 41 18 29 7 / 70 10 60 60 HVR 40 -8 3 -12 / 90 40 20 40 LWT 44 -3 7 -8 / 60 10 40 70

TFX WATCHES/WARNINGS/ADVISORIES

Winter Weather Advisory until 8 PM MST this evening for Cascade County below 5000ft-Eastern Glacier, Western Toole, and Central Pondera-Eastern Pondera and Eastern Teton-Eastern Toole and Liberty-Gates of the Mountains-Northern High Plains-Southern High Plains.

High Wind Warning until 8 PM MST this evening for Bears Paw Mountains and Southern Blaine-Fergus County below 4500ft-Judith Basin County and Judith Gap-Little Belt and Highwood Mountains- Snowy and Judith Mountains.

Winter Storm Warning until 11 PM MST this evening for Northern Blaine County.

Winter Weather Advisory until 11 PM MST this evening for Hill County.

Winter Weather Advisory until 5 PM MST this afternoon for East Glacier Park Region-Elkhorn and Boulder Mountains-Gallatin and Madison County Mountains and Centennial Mountains-Northwest Beaverhead County-Ruby Mountains and Southern Beaverhead Mountains-Southern Rocky Mountain Front-Upper Blackfoot and MacDonald Pass.