textproduct: Great Falls

KEY MESSAGES

- Light snow diminishes today from north to south with Arctic air settling in over the entire forecast area for the next couple of days.

- Another round of light snow moves from north to south Saturday into Sunday, heaviest over and near the Little Belts.

- Dry conditions and moderating temperatures are in the forecast for most locations Sunday into early next week.

DISCUSSION

/Issued 253 AM MST Fri Jan 23 2026/

- Meteorological Overview:

Shortwaves rotating within a cold northwesterly aloft will maintain periods of light snow and Arctic chill for most locations over the next couple of days. Light snow this morning will diminish and end in a north to south fashion later this morning. Temperatures will struggle to exceed the single digits and teens today thanks to cold air advection supported by H700/H500 temperatures near -20/-35C respectively.

Another shortwave surges southward and brings another round of light snow and gusty north to northwesterly winds Saturday into Sunday. This will also serve to reinforce the Arctic air in place, though overall temperatures will be slightly milder than today.

The northwesterly flow aloft remains in place heading into next week, but the temperatures aloft warm markedly and the shortwaves passing through will be more subtle. This will result breezy and dry conditons with temperatures warming well above average for most locations by mid-week. The notable exception to this will be for the normally cooler Milk River Valley where the shallow cold air will hang on a bit longer than other areas.

Moist ensembles bring in another trough moving into the interior west towards the end of the workweek, but there are disagreements on whether the main circulation stays over the northern tier or if it splits off and dives southward into the great Basin and desert southwest. The former solution would result in a brief period with below average temperatures, mostly for northern areas, and another round of light snow. Should the energy move south, then drier and milder conditions will prevail. - RCG

- Forecast Confidence & Scenarios:

Arctic chill today through Saturday morning...

The combination of east to northeasterly winds and continued cold air advection has brought wind chills a bit lower than expectations. Many plains locations east of I15 were reporting wind chills approaching and exceeding -25F, so this morning's cold weather advisory was expanded to include Chouteau, Fergus, and eastern Toole and Liberty counties. Cold will once again become problematic tonight into Saturday morning with forecast minimum windchills even colder than tonight in some cases; however, increasing cloud cover and slight warming aloft later this evening may result in a shorter period with wind chills falling into the -25 to -35F range. For this reason, I held off on issuing any cold products for now. Saturday night and Sunday morning will be another time to consider cold weather products with eh arrival of a reinforcing shot of Arctic air. Areas along the Hi-Line will be most susceptible to the frigid conditions.

Light snow today and again Saturday into early Sunday...

Light snow may be a bit stubborn to shut off this morning as it moves southward, but accumulations and impacts should be negligible. The bigger concerns will come with the approaching shortwave Saturday into early Sunday. Both deterministic and probabilistic guidance are highlighting higher snowfall totals with this upcoming system, especially for the Little Belt/Snowy Mountains and there northerly upslope foothills. Probabilities are round 70% for a 2 to 4 inch snowfall over the higher terrain and around an inch or so over the nearby hills and plains. A winter weather advisory may be considered for these mountain zones should this trend continue to gain traction. - RCG

AVIATION

23/12Z TAF Period

Areas of light snow and associated low VFR/MVFR cigs/vis will slowly improve in a north to south fashion through 23/20Z. Another shortwave approaches from the northwest tonight into Saturday and initially brings increased mid- and higher level cloudiness followed by another round of light snow and degraded flight categories. Mountains will be obscured through much of the TAF period. - RCG

PRELIMINARY POINT TEMPS/POPS

GTF 10 -3 23 1 / 30 10 50 80 CTB 11 -3 19 -4 / 10 10 40 30 HLN 13 -2 24 5 / 30 0 30 40 BZN 15 -4 22 3 / 20 0 20 30 WYS 20 -13 18 -7 / 10 0 10 30 DLN 20 -7 26 5 / 10 0 10 20 HVR 2 -11 9 -8 / 10 10 30 20 LWT 6 -7 18 -4 / 30 10 70 80

TFX WATCHES/WARNINGS/ADVISORIES

Cold Weather Advisory until 11 AM MST this morning for Bears Paw Mountains and Southern Blaine-Eastern Toole and Liberty-Fergus County below 4500ft-Hill County-Northern Blaine County-Snowy and Judith Mountains-Western and Central Chouteau County.