textproduct: Great Falls

KEY MESSAGES

- Lingering patchy fog over the river valleys and the wind protected basins of central and southwest Montana will dissipate later this morning.

- Fast moving weather systems will bring periods of breezy to windy conditions and spotty mountain precipitation later today and through the weekend into next week.

- The strongest winds look to occur along the Rocky Mountain Front Friday into Saturday and again on Sunday.

- Temperatures will generally run above average for the next seven days.

DISCUSSION

/Issued 313 AM MST Thu Nov 5 2026/

- Meteorological Overview:

An approaching Pacific trough will displace the ridge aloft to the east and bring increased winds and even some spotty mostly mountain rain and snow showers later today. This system will generally be moisture starved and will offer little to no precipitation for most locations. H700 winds dont look overly impressive, generally in the 30 to 40 kt range, but this will bring a definitive shift towards breezy to windy conditions, especially following the light wind regime of the last several days.

Ridging aloft then builds back in for the first half of the weekend, but a trough passing to our north will tighten the pressure gradient along the Canadian border. Forecast soundings have been steadily becoming more bullish in regards to mountain wave activity bringing bouts of strong winds along the Northern Rocky Mountain Front and adjacent plains Friday into Saturday, with localized wind gusts between 60 and 80 mph. Winds dont look quite as strong for the plains east of the highway 89 corridor, although gusts between 30 and 50 mph will be common.

A slightly deeper trough moves in Sunday into Monday and brings another round of winds and some more light mountain precipitation, mostly along the northern divide. This system will have a broader wind shield with H700 peaking at well over 60 kts; however, there may be more reliance on diurnal mixing for surface transfer momentum due to less ensemble confidence in more robust mountain waves. The winds certainly look to cover more real estate, but the top winds may not be as strong as the previous system if mountain waves are weaker and less frequent. The progressive westerly flow pattern continues well into next week with another peak in winds heading towards the mid- week period. - RCG

- Forecast Confidence & Scenarios:

...Stronger westerly winds Friday into Saturday and again on Sunday...

NBM probabilistic guidance continues to highlight Friday into Saturday for the strongest winds, with the chance for 55 mph + wind gusts running roughly 70 to 90% along the Rocky Mountain Front and the plains along and west of highway 89 and along and west of I15 over Glacier County. The 40 to 70% chance for 75 mph wind gusts is starting to expand beyond immediate eastern slopes of the Northern Rocky Mountain Front given better agreement on timing and stronger mountain wave activity. The confounding factor is the increasingly northwesterly component with height, which may preclude wind speed optimization, mostly during the day on Friday. This was not enough to negate the decision to issue a high wind watch for the Northern Rocky Mountain Front zones and eastern Glacier County given the overall favorable trends. Note that the plains east of I15 also look windy during this time despite not being strong enough to warrant wind product issuance at this time. Wind gusts in the 30 to 50 mph gusts will be common for these locations, especially the central MT highway 87/200 corridor.

Confidence for another round of stronger winds Sunday into Monday has gained traction over the last 24 hours. Ensembles are in better agreement with a broader 50 to 70 kt H700/H500 jet streak moving through the Northern Rockies during this time. More precise details in regards to mountain waves and diurnal mixing still need to be sorted out, but NBM probabilistic guidance is increasing, with up to a 90% chance for 55 mph gusts or higher along the Rocky Mountain Front and a 20 to 40% chance for 55 mph gusts or greater along the central MT highway 87/200 corridor and along portions of the Hi-Line. - RCG

AVIATION

05/12Z TAF Period

MVFR/IFR/LIFR degradations from patchy fog and stratus, mostly for KHLN/KHVR/KWYS, will trend towards VFR between 05/15 and 05/18Z. Otherwise, VFR conditions will generally prevail under increasing mid and higher level cloudiness. Cloud cover and even some spotty mostly mountain rain/snow showers will peak around 06/00Z during a Pacific trough passage. Expect the IFR/LIFR stratus and vicinity fog to return to KWYS by 06/06Z. - RCG

PRELIMINARY POINT TEMPS/POPS

GTF 53 34 54 44 / 0 0 0 0 CTB 48 32 51 40 / 10 0 0 0 HLN 48 28 51 35 / 10 10 0 0 BZN 47 27 47 30 / 10 20 0 0 WYS 41 21 39 20 / 10 20 0 0 DLN 43 25 47 27 / 10 10 0 0 HVR 51 32 53 38 / 0 0 0 0 LWT 55 31 54 37 / 0 0 0 0

TFX WATCHES/WARNINGS/ADVISORIES

High Wind Watch from Friday afternoon through Saturday morning for East Glacier Park Region-Eastern Glacier, Western Toole, and Central Pondera-Northern High Plains.