textproduct: Great Falls

KEY MESSAGES

- Strong, gusty westerly winds along the Rocky Mountain Front and the plains will slowly diminish in a west to east fashion heading towards the evening hours.

- Accumulating snow over the higher terrain of Glacier National Park becomes more showery in nature by this afternoon while lighter shower activity continues along the Hi-Line.

- Unsettled and cooler conditions continue this weekend into early next week.

- Sunday through Monday looks to be coolest period with the best opportunity for mountain and some lower elevation snow.

DISCUSSION

/Issued 516 AM MDT Thu May 14 2026/

- Meteorological Overview:

Westerly flow as much as 4 standard deviations above climatology will continue to bring strong winds along the Rocky Mountain Front and the north-central plains through at least this evening. Once the robust winds aloft pass, a mid-level jet will maintain a moderate brand of breezy to windy conditions. Aside from some morning mountain snow along the immediate eastern slopes of the Northern Rocky Mountain Front and scattered showers along the Hi- Line, drier air will preclude widespread precipitation through the first half of the weekend. Temperatures will generally remain near to slightly below average.

Ensembles continue to highlight a split flow trough and attendant cold front moving through the Northern Rockies Sunday and Monday. This looks to bring a period of below average temperatures and more widespread precipitation, including at least some all elevation snow thanks to H700 and H500 temperatures as low as (-10C/-30C) near the trough axis. Snow impacts will be highly dependent on the timing of day with nighttime and early morning snow being more impactful. Since this is a split flow trough, it's difficult to determine the track of the closed circulation, should one even develop. A northwesterly flow aloft looks to develop in the wake of this system for slow warming heading into the middle of next week. - RCG

- Forecast Confidence & Scenarios:

Today's strong winds and Rocky Mountain Front snow...

Winds so far have been a little subdued compared to expectations with the strongest gusts being more confined to the normally more wind prone locations. The Southern Rocky Mountain Front has been observing the strongest winds with wind gusts in the 70s and 80s and even sustained winds above 50 mph. The winds aloft will slowly decrease in a west to east fashion later this morning into the afternoon, though diurnal mixing will cover the slack, especially for eastern areas. Peak winds west of I15 looks to occur around mid- morning while areas to the east peak in the afternoon and early evening. No changes have been made to the current high wind products, though a few areas my fall short of reaching high wind criteria, most notably the Helena Valley. Given that isolated gusts still can't be ruled out quite yet, I maintained the warning for this forecast package. Also, some of the products may be let go earlier than the current expiration times, but I left as is for now to give the day shift the opportunity to determine any trends and take action from there.

Mountain will continue along the immediate eastern slopes of the Northern Rocky Mountain Front through the morning, particularly over the higher terrain of the Glacier National Park. Still looking at around a 3 to 6 inch wind whipped snowfall at Logan's Pass when things are all set and done. The winter weather advisory will remain in effect through noon to cover slushy road accumulations, isolated tree damage/power outages, and dangerous conditions for outdoor interests. - RCG

AVIATION

14/18Z TAF Period

Gusty west to southwest winds continue across North-Central MT through the afternoon today. Gusts of up to 45 to 55kts will be possible early this afternoon. The winds will also pick up patchy blowing dust. Generally, visibilities will prevail VFR but can't rule out a few brief MVFR visibilities at KGTF and KHVR. Winds will decrease in the evening, but will remain breezy through the rest of the TAF period. -Wilson

PRELIMINARY POINT TEMPS/POPS

GTF 64 44 63 40 / 10 0 0 0 CTB 59 39 58 34 / 20 0 0 0 HLN 65 41 63 37 / 0 0 0 0 BZN 68 37 65 34 / 0 0 0 0 WYS 64 32 63 30 / 0 0 0 0 DLN 68 36 65 35 / 0 0 0 0 HVR 69 42 65 36 / 60 0 10 0 LWT 64 40 61 36 / 10 0 0 0

TFX WATCHES/WARNINGS/ADVISORIES

High Wind Warning until midnight MDT tonight for Bears Paw Mountains and Southern Blaine-East Glacier Park Region-Eastern Glacier, Western Toole, and Central Pondera-Fergus County below 4500ft-Hill County-Northern Blaine County-Northern High Plains- Snowy and Judith Mountains-Southern High Plains-Southern Rocky Mountain Front-Upper Blackfoot and MacDonald Pass-Western and Central Chouteau County.

High Wind Warning until 6 PM MDT this evening for Cascade County below 5000ft-Eastern Pondera and Eastern Teton-Eastern Toole and Liberty-Gates of the Mountains-Judith Basin County and Judith Gap.