textproduct: Great Falls

KEY MESSAGES

- High Winds will lead to dangerous travel, especially for high profile vehicles, and backcountry recreation along the Rocky Mountain Front and portions of the Hi-Line through this evening.

- Highs will be well above normal today, with temperatures cooling to near normal on Sunday.

- Overall dry conditions are expected through Monday, with low chances for precipitation arriving on Tuesday across Southwest and Central Montana.

DISCUSSION

/Issued 1215 AM MDT Sat Oct 17 2026/

- Meteorological Overview:

Upper level ridging over the Western CONUS early this morning will continue to be flattened as a potent shortwave over the Gulf of Alaska slides east over British Columbia and the Canadian Prairie Provinces through the day today. Increasing cross barrier flow over the Northern Rockies will lead to strengthening southwest to west winds across Southwest through North Central Montana, most notably along the Rocky Mountain Front and International Border. These downsloping southwest to west winds will lead to another day of above normal temperatures across the region, with highs peaking in the mid-60s to near 70 degrees in the valleys of Southwest and Central Montana to the low 70s to near 80 degrees over the plains of Central and North Central Montana. "Cooler" temperatures are then expected into the day on Sunday in wake of a weak Pacific front, which will slide east and over the Northern Rockies late tonight, with highs topping out in the upper 50s to low 60s. Despite persistent zonal flow over the Northern Rockies on Sunday weak surface high pressure settling in over the Pacific Northwest and Northern Rockies will help to support light surfaces winds and continued dry conditions. - Moldan

By Monday morning, weak ridging takes its place as an upper level trough begins to move down the Pacific Coast towards northern California. This will create southwesterly flow aloft by Monday evening, which will last through the middle of next week, allowing for seasonably average temperatures. By Thursday, the trough will have moved south of the Great Basin, creating a more direct southerly flow aloft, before moving northeast towards Wyoming. This will allow temperatures to warm on Thursday before cooling down on Friday. Increased moisture aloft will get carried north by the upper level southerly low, increasing precipitation chances towards the end of next week into next weekend. There remains shearing and splitting in the trough late Thursday into next weekend, so while one can expect cooling temperatures and increased precipitation chances late in the forecast period, confidence in the forecast specifics for this time remains low. -Dzomba

- Forecast Confidence & Scenarios:

High Winds through this evening...

Confidence is very high that High Winds will develop along and west of a Sweet Grass, to Cut Bank, to Dupuyer, to Choteau, to Augusta line by the late morning hours today and persist through the evening hours tonight. The strongest winds within the region are likely to occur across the Blackfeet Nation, most notably in and near the Browning and Heart Butte communities where isolated wind gusts approaching 90 mph will be possible. Where confidence begins to decrease is for areas east of Cut Bank along the US Hwy 2 corridor, with the exception of areas immediately downwind of the Sweet Grass Hills where localized strong winds will occur due to mountain wave activity. Confidence is lower for these areas along the US Hwy 2 corridor given limited support for deep mixing within BUFKIT data; however, with 60kts at H700 overspreading these areas within a favorable window for mixing and subsequent momentum transfer to the surface it will not take much for strong winds to materialize across Hill and Blaine counties. For now I will hold course with not expanding the areal footprint of the High Wind Warning further east, but there is a 10% chance that wind gusts could exceed 60 mph in Hill and Northern Blaine counties; in addition to the wind prone areas along the northern slopes of the Little Belt Mountains.

Below is a table of NBM5.0 wind gust scenarios for select locations across North Central and Central Montana, with the "Low End" Scenario being the NBM10Pct, "Most Likely" Scenario being the NBM50Pct, and the "High End" Scenario being the NBM90Pct.

24 Hour Maximum Wind Gusts LOCATION Low End | Most Likely | High End East Glacier 60 MPH | 65 MPH | 70 MPH Browning 65 MPH | 70 MPH | 80 MPH Cut Bank 50 MPH | 60 MPH | 70 MPH Shelby 35 MPH | 45 MPH | 55 MPH Havre 45 MPH | 50 MPH | 60 MPH Great Falls 45 MPH | 50 MPH | 60 MPH Lewistown 25 MPH | 35 MPH | 40 MPH

- Moldan

AVIATION

17/06Z TAF Period

While VFR conditions will prevail throughout the entirety of the 1712/1812 TAF period strong, west winds over the plains of Central and North Central Montana will bring instances of low level wind shear and mountain wave turbulence. Greatest concern for low level wind shear will exist through 18z prior to deeper mixing, with mountain wave turbulence persisting through 06-09z Sunday. Strong southerly winds will also be experienced within the Madison River Valley (i.e. KEKS terminal) from the late morning through evening hours today. - Moldan

PRELIMINARY POINT TEMPS/POPS

GTF 72 42 61 39 / 0 0 0 0 CTB 69 34 58 30 / 0 0 0 0 HLN 70 35 62 35 / 0 0 0 0 BZN 67 33 60 30 / 0 0 0 0 WYS 57 23 59 22 / 0 0 0 0 DLN 65 31 61 31 / 0 0 0 0 HVR 78 37 62 33 / 0 0 0 0 LWT 73 39 59 35 / 0 0 0 0

TFX WATCHES/WARNINGS/ADVISORIES

High Wind Warning from 9 AM this morning to midnight MDT tonight for East Glacier Park Region-Eastern Glacier, Western Toole, and Central Pondera-Eastern Toole and Liberty-Northern High Plains- Southern High Plains-Southern Rocky Mountain Front.