textproduct: Great Falls

KEY MESSAGES

- Dense freezing fog will continue along the Hi-Line this morning before dissipating with a chance it could redevelop overnight tonight.

- A quick moving band of snow may impact the morning commute across Southwest Montana including Bozeman Pass.

- More widespread moderate to heavy snow is possible across north-central Montana Thursday through Friday.

- Coldest air of the season so far will arrive this weekend.

DISCUSSION

/Issued 1251 AM MST Wed Nov 26 2025/

- Meteorological Overview:

Dense freezing fog will continue through the morning along portions of the Hi-Line east of Cut Bank with reduced visibilities and slick roads being the main concerns. A brief shortwave moving through the area will bring snow showers to the mountains and portions of southwest Montana through the morning before clearing out by the mid afternoon.

The next wave moves into the region late Thursday and phases with additional energy dropping south from Canada while tracking across the area Thursday night and Friday. Snow looks to develop across primarily north-central MT ahead of the initial wave by Thursday afternoon and increases Thursday night as the additional energy arrives with snow spreading across most of area late Thursday night through Friday morning. A colder airmass and strong surface high pressure surges southward from AB Thursday night through Friday morning bringing gusty north winds and falling temperatures with the northerly flow supporting snow through Friday afternoon in upslope favored locations near the central and southwest MT mountain rages.

Cold high pressure settles over the region this weekend for mainly dry conditions with afternoon temperatures in the teens and twenties and overnight lows in the single digits above/below zero. Looking ahead to next week, the area remains under cold cyclonic NW flow between deep/large scale troughing in central Canada and ridging in the Eastern Pacific. There is still some significant differences among the various model ensembles in the exact position of these features and smaller scale disturbances moving through the NW flow. Overall cool to below average temperatures are likely to persist, though some moderation in temperatures is possible with additional chances for snow associated with disturbances moving through. Hoenisch/thor

- Forecast Confidence & Scenarios:

Freezing Fog Along the Hi-Line:

Dense freezing fog will continue across the Hi-Line through the morning before lifting in the afternoon. Currently hi-res model guidance shows the potential for redevelopment tonight into Thursday morning in the same areas east of I-15. One of the primary concerns will be that the freezing fog may lead to a glaze of ice on some surfaces creating slippery sidewalks and roads.

Snow Today:

Snow showers will generally be confined to the mountains although some light snow at lower elevations in southwest Montana, is possible through the morning. One of the main concerns will be along Bozeman Pass as the heaviest snow is expected to hit right around the morning commute. Brief periods of moderate to heavy snow are possible which may reduce visibility and cause slippery conditions along the pass.

Additionally, periods of moderate snow are possible in the Little Belts including Kings Hill Pass with similar impacts of reduced visibility and slippery roads possible. In general this snow is expected to clear out by the middle of the afternoon with a brief lull in activity before the main system arrives Thursday afternoon.

Snow and Cold Thursday and Beyond:

There is growing confidence in at least moderate impacts across portions of north-central Montana Thursday and Friday along the Northern Rockies into the western half of the northern plains. 4 to 8 inches at lower elevations highlighted in the current Winter Storm Watch is possible with up to 10 inches possible at higher elevations in the Northern Rockies.

Although snow amounts have continued to trend upwards across the rest of north-central Montana, there is not enough confidence to warrant adding it to the Winter Storm Watch. Should future model updates show greater probabilities further east then the watch may need to be expanded at a later time. -thor

AVIATION

26/12Z TAF Period

Light to moderate snow continues to overspread portions of North Central through Southwest Montana this morning as an upper level disturbance moves overhead, most notably along and southwest of a KCTB to KLWT line and northeast of a KDLN to KWYS line. Predominately IFR/MVFR conditions will occur within this area of snow through 15-18z; however, temporary LIFR conditions can't be ruled out at times. Additionally, fog continues to persist within the Milk River Valley, with this fog expected to gradually dissipated across the KHVR terminal through 18z but IFR/MVFR CIGS may linger longer. Confidence in these low CIGS persisting over the KHVR terminal was too low at this time to prevail, but it should be noted that there is the potential for these CIGS to linger through much of the 2612/2712 TAF period. Mountains will be obscured for much of the next 24 hours. - Moldan

PRELIMINARY POINT TEMPS/POPS

GTF 42 24 36 19 / 50 0 50 80 CTB 38 15 31 12 / 10 0 50 90 HLN 41 27 41 21 / 50 10 40 60 BZN 41 23 44 24 / 70 10 20 30 WYS 33 17 38 20 / 80 10 30 20 DLN 44 27 48 26 / 20 10 10 10 HVR 29 10 28 15 / 10 0 20 90 LWT 38 22 39 16 / 50 10 30 70

TFX WATCHES/WARNINGS/ADVISORIES

Dense Fog Advisory until 11 AM MST this morning for Eastern Toole and Liberty-Hill County-Northern Blaine County.

Winter Storm Watch from Thursday afternoon through Friday afternoon for Cascade County below 5000ft-East Glacier Park Region-Eastern Glacier, Western Toole, and Central Pondera- Eastern Pondera and Eastern Teton-Eastern Toole and Liberty- Northern High Plains-Southern High Plains-Southern Rocky Mountain Front-Western and Central Chouteau County.

Winter Weather Advisory until 10 AM MST this morning for Big Belt, Bridger and Castle Mountains-Little Belt and Highwood Mountains.