textproduct: Great Falls

KEY MESSAGES

- Gusty west winds develop from the late morning through evening hours.

- Some minor snow accumulations are expected above 6500 feet across Glacier National Park.

- High temperatures today will be 10 to 15 degrees below normal.

DISCUSSION

/Issued 515 AM MDT Sun Aug 30 2026/

- Meteorological Overview:

Showers and thunderstorms will gradually exit to the east of the Northern Rockies through the late morning and afternoon hours, with increasing westerly winds replacing the departing precipitation for the remainder of the day. High temperatures in wake a Pacific cold front will only rise into the mid-50s to near 70 degrees today, which is 10 to 15 degrees below normal. Falling snow levels along the Continental Divide, specifically the Glacier National Park region, is expected to lead to some minor snowfall accumulations prior to precipitation ending.

Quasi-zonal flow to begin the work week will back to the southwest through the day on Tuesday as upper level troughing digs south along the western seaboard. This trough will deepen through the middle of the work week while slowly drifting east over the Western CONUS, which will place the Northern Rockies beneath southwest to southerly flow through the remainder of the forecast period. Pacific moisture streaming northeast to north within this flow will support daily chances for showers and storms from Tuesday through the upcoming week, especially over the mountains of Southwest Montana and along the Continental Divide. Temperatures will see-saw between 5 degrees above to below normal through the upcoming work week within this pattern, with periods of gusty south winds developing in the north- south orientated valleys of Southwest Montana as the upper level flow becomes more southerly in nature. - Moldan

- Forecast Confidence & Scenarios:

Gusty Winds through the day today...

Confidence remains high that gusty west winds will develop across all of Southwest through North Central Montana today, most notably from the late morning through evening hours. There is high confidence that frequent wind gusts of between 30-40 mph will occur across the region through this timeframe, with the strongest winds occurring along the Rocky Mountain Front west of the I-15 corridor and along the Montana Hwy 200/US Hwy 87 corridors between Great Falls and Lewistown. One notable change from the past 48 hours has been a northward shift in the strongest H850-700 winds, which are now prog'd to reside between the Montana Hwy 200 and US Hwy 2 corridors. This northward shift from the past 48 hours, which had been showing the core of strongest winds residing over the Montana Hwy 200 corridor, has resulted in an increase (albeit still low) in probabilities for wind gusts to exceed 55 mph along the US Hwy 2 corridor. It is not out of the realm of possibility that a few wind prone locations across Glacier County and in lee of the Sweet Grass Hills will reach or exceed High Wind criteria today; however, given that these occurrences will be far and few between we will continue to hold off on issuing any High Wind Warnings. None-the-less, those traveling in high profile vehicles should be prepared for strong cross winds.

Listed below are the NBM5.0 probabilities for wind gusts to exceed 35, 45, and 55 mph for select locations across North Central, Central, and Southwest Montana.

Sunday's Wind Gusts Probabilities LOCATION > 35 mph | > 45 mph | > 55 mph Browning 100% | 85% | 20% Cut Bank 100% | 85% | 25% Havre 95% | 50% | 10% Great Falls 95% | 50% | <5% Lewistown 65% | 5% | 0% Helena 80% | 15% | <5% Bozeman 40% | 5% | <5% Dillon 60% | 5% | 0% Ennis 50% | 5% | 0% West Yellowstone 75% | <5% | 0%

Accumulating Snow in the Mountains of Glacier National Park...

Confidence in minor snowfall accumulations has increased for the mountains of Glacier National Park, mainly for those elevations above 6500ft. Model guidance has settled in on better timing of precipitation moving across the park as snow level fall, with this overlap between both precipitation and "low" snow levels promoting some minor accumulations of up to 1-2" for the higher peaks. Those looking to recreate in the backcountry of Glacier National Park above 6500ft should be prepared for wet and raw conditions, along with the potential for slippery trail conditions. - Moldan

AVIATION

30/18Z TAF Period

VFR conditions will prevail through the period with gusty winds out of the west impacting all terminals this afternoon until late tonight. Light to occasional moderate turbulence from the surface up to FL160 is expected over and 25 miles downwind of the Rocky Mountain Front. Light icing is also expected in cloud from FL080 to FL180 over North Central MT.

For KGTF: Westerly winds of 20 KT gusting to 30 KT is expected this afternoon with gradual calming into the evening behind the front. Peak crosswinds are expected to occur between 20Z and 00Z as westerly winds gust near 30 KT. Crosswind exceedance will be primarily during gusts however sustained winds will be close to threshold throughout the day. - Akins

PRELIMINARY POINT TEMPS/POPS

GTF 47 78 49 84 / 0 0 0 0 CTB 45 74 47 83 / 10 0 0 0 HLN 44 78 49 83 / 0 0 0 0 BZN 40 77 45 80 / 0 0 0 10 WYS 30 70 35 70 / 0 0 20 50 DLN 39 79 44 79 / 0 0 0 20 HVR 49 77 50 87 / 10 0 0 0 LWT 44 75 48 82 / 0 0 0 0

TFX WATCHES/WARNINGS/ADVISORIES

None.