textproduct: Great Falls

KEY MESSAGES

- Mild and breezy to windy conditions will abruptly change to colder and very windy conditions on Tuesday.

- 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.

DISCUSSION

/Issued 231 PM MST Mon Feb 16 2026/

- Meteorological Overview:

A major weather pattern change remains on track for tomorrow 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:

Snowfall accumulations for this event will be greatest along the ID/WY border where the duration of snowfall will be longest and include the orographically forced precipitation tonight followed by the frontal precipitation on Tuesday. Further north, a period of moderate snowfall is expected along the continental divide early to mid- day on Tuesday with some enhancement to the frontal precipitation as the beneath the mid level wave and somewhat favorable upper level jet placement. Elsewhere across central and SW MT, precipitation coverage and duration will be relatively short, limiting the potential for more than an inch or two of snow accumulation. While precipitation lifting across central and southwest MT will be less organized, strong cooling aloft will support a convective nature with brief but intense snow showers or bands possible. In addition, these more convective showers may bring strong winds to the surface with quickly changing visibility. Gusty winds and blowing snow will also be a concern across the northern tier of counties and south along areas adjacent to the Rocky Mountain Front. Northerly winds will be enhanced along the plains adjacent to the Rocky Mtn front late Tuesday through Tuesday evening as surface high pressure surges southward as well as behind the exiting inverted surface trough across Hill and Blaine counties. While snow amounts in Hill and Blaine counties are only in the 1-3 inch range, there is also some potential for icy road surfaces with precipitation there possibly beginning as rain Tuesday afternoon before changing to snow.

A cold airmass funneling south through AB will begin to move south along the Rocky Mtn Front Tuesday morning before a stronger surge of high pressure and the colder airmass moves south across the area Tuesday night behind the departing surface low. Sharply falling temperatures will spread south and east across north- central MT from Tuesday afternoon through Tuesday night with the colder air modifying some as it filters south through the Helena and Canyon Ferry areas Tuesday night and Wednesday and eventually into the southwest MT valleys Wednesday night. Temperatures in the single digits above/below zero will be coldest near the AB border where enough wind will persist to push wind chills as low as around -20 to -25 F across portions of Glacier, Liberty and Toole counties. Temperatures across north-central MT on Wednesday will be around 40-50 degrees colder than those of today (Monday afternoon). While not extreme or unusual for February, this will be a significant change and those with outdoor activities planned or tending to newborn livestock should prepare for wind chills as low as 10 below to 15 below zero across much of north-central MT Tuesday night through Wednesday night. Hoenisch

AVIATION

17/00Z TAF Period

General VFR conditions and decreasing winds tonight for most locations along and north of I90; however, MVFR/IFR clouds, snow, and mountian obscuration will increase over southwest MT, especially after 17/06Z. Also, southerly surface winds will remain gusty in the KEKS area. On Tuesday, the responsible Pacific cold front moves in from the southwest and send bands of snow and gusty west to southwesterly surface winds into central/southwest MT between 17/12 and 17/20Z. Farther north, a Canadian cold front will bring similar conditions to the plains in a northwest to southeast fashion, though the wind direction will be more north/northwesterly and wind gusts may exceed 50 kts at times, especially along the Hi-Line. Note that the leading edge of precipitation may begin as rain over the plains east of I15. - RCG

PRELIMINARY POINT TEMPS/POPS

GTF 29 35 4 11 / 10 90 30 40 CTB 20 28 -6 3 / 10 90 20 20 HLN 29 39 7 17 / 20 90 30 50 BZN 31 43 14 28 / 20 80 20 50 WYS 23 33 8 29 / 90 90 40 90 DLN 31 40 19 33 / 70 60 10 40 HVR 28 40 -2 11 / 0 80 40 10 LWT 30 43 2 13 / 10 60 20 30

TFX WATCHES/WARNINGS/ADVISORIES

Winter Weather Advisory from 2 AM to 8 PM MST Tuesday for Eastern Glacier, Western Toole, and Central Pondera-Eastern Toole and Liberty-Gates of the Mountains-Northern High Plains- Southern High Plains.

High Wind Warning from 9 AM to 8 PM MST Tuesday 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 Weather Advisory from 11 AM to 11 PM MST Tuesday for Hill County-Northern Blaine County.

Winter Weather Advisory from 2 AM to 5 PM MST Tuesday for East Glacier Park Region-Elkhorn and Boulder Mountains-Northwest Beaverhead County-Southern Rocky Mountain Front-Upper Blackfoot and MacDonald Pass.

Winter Weather Advisory from 11 PM this evening to 5 PM MST Tuesday for Gallatin and Madison County Mountains and Centennial Mountains-Ruby Mountains and Southern Beaverhead Mountains.