textproduct: Great Falls

KEY MESSAGES

- Temperatures trend warmer through Saturday before cooling slightly Sunday into early next week.

- Gusty to locally strong westerly winds develop along the Rocky Mountain Front and the plains Friday and especially Saturday.

- Pacific weather systems look to bring cooler temperatures and periods of rain and mostly mountain snow heading towards the second half of next week.

DISCUSSION

/Issued 125 PM MDT Thu Oct 15 2026/

- Meteorological Overview:

Ridging aloft migrates into the Northern Rockies and brings continued clearing skies tonight, along with some patchy AM fog over the wind protected valleys of southwest and north-central MT. H500 heights peak above 580 dm and warms high temperatures well into the 60s and 70s Friday and Saturday. The combination of increased westerly flow aloft and deep layer mixing will also bring gusty to locally strong winds along the Rocky Mountain Front and the plains during this timeframe. The strongest winds will occur Saturday afternoon when H700 flow increases to the 50 to 70 kt range in advance of a fast approaching trough traveling eastward along the Canadian border. Forecast afternoon RH's were lowered to the upper teens to middle 20s for most lower elevation locations.

A more relaxed zonal flow sets up on Sunday for slightly cooler temperatures and lighter winds. A closed mid-level low then looks to move onto the Pacific NW coast on Monday before heading southeastward into California and towards the Great Basin area by mi- week. This will bring a southerly flow aloft and a few passing showers over the Northern Rockies while temperatures remain roughly near average.

At least half of the ensemble suites highlight another trough approaching the Northern Rockies next Friday/Saturday. Similar to the aforementioned closed low, this new trough will be undergoing shearing and splitting, which decreases forecast position and timing confidence. Overall, there's a general expectation for cooling temperatures and increased instances of rain and mostly mountain snow heading into next weekend. - RCG

- Forecast Confidence & Scenarios:

Gusty to strong winds along the Rocky Mountain Front and the plains Friday and Saturday...

Breezy to windy conditions develop along the Rocky Mountain Front and the plains Friday afternoon, with localized gusts over 50 mph along the immediate eastern slopes of the front. The windiest period will be Saturday afternoon when westerly flow aloft increases and diurnal mixing transfers some stronger gusts to the surface. Areas along the Rocky Mountain Front and plains west of I15 look to see routine gusts over 50 mph and have a 50 to 80% chance (highest for the eastern slopes of the front) for instantaneous gusts over 70 mph. Plains locations to the east of I15 will generally see winds gusting in the 30 to 50 mph range, most frequently Saturday afternoon.

Impacts will be greatest for the aforementioned areas west of I15 and will include difficult conditions for outdoor recreation over portions of Glacier National Park and neighboring areas of higher terrain. There will also be difficult travel for those operating high profile vehicles or pulling light weight trailers, especially along highway 89 from Chouteau to the Canadian border. The inherited high wind watch remains valid and was left as is for this forecast package. - RCG

AVIATION

16/00Z TAF Period

VFR conditions will prevail at all terminals during this TAF Period. There is a low chance for fog at the KBZN and KHLN terminals between 16/06Z and 16/16Z. After 16/18Z it will be breezy at the KCTB and KGTF terminals. Across North-central Montana between 16/12Z and the end of this TAF Period there will be isolated instances of low-level wind shear. -IG

PRELIMINARY POINT TEMPS/POPS

GTF 35 67 47 70 / 0 0 0 0 CTB 27 66 43 67 / 0 0 0 0 HLN 29 61 33 68 / 0 0 0 0 BZN 25 59 30 65 / 0 0 0 0 WYS 17 55 19 55 / 0 0 0 0 DLN 26 57 30 61 / 0 0 0 0 HVR 27 67 42 75 / 0 0 0 0 LWT 26 68 45 73 / 0 0 0 0

TFX WATCHES/WARNINGS/ADVISORIES

High Wind Watch from Saturday morning through Saturday evening for East Glacier Park Region-Eastern Glacier, Western Toole, and Central Pondera-Northern High Plains-Southern High Plains- Southern Rocky Mountain Front.