textproduct: Great Falls

KEY MESSAGES

- Hot this weekend with afternoon temperatures near daily records.

- Heat, dryness and afternoon breezy to locally windy conditions will bring elevated fire weather concerns, especially across southwest Montana.

- Not as hot next week with increasing chances for thunderstorms.

DISCUSSION

/Issued 349 AM MDT Sat Jul 11 2026/

- Meteorological Overview:

Upper level ridging continues to amplify and extend northeast into the Northern US Plains this weekend, bringing several days of excessive heat to the region with afternoon temperatures near daily records today and tomorrow. A few isolated showers/thunderstorms moving across north-central MT early this morning in association with a subtle shortwave disturbance and some mid-level moisture will lift out of the area by mid-morning. With the ridge axis centered east of the area a moderate southwesterly flow aloft remains in place with afternoon mixing tapping into this for breezy winds this afternoon and again Sunday. By late Sunday, shortwave energy lifting through southern BC will compress the the NW periphery of the upper ridge and allow low-level thermal trough to shift east across the area Sunday evening. This will lead to enhanced southwest winds Sunday afternoon across much of the area. Mid-level moisture also begins to stream northeast across the Northern Rockies late Sunday and this could lead to some increased cumulus development and perhaps an isolated high-based shower or thunderstorms Sunday afternoon/evening, primarily across north-central MT. The hottest daytime maximum temperatures are likely on Sunday as 500MB heights/thickness and 700MB temps peak with only slight moderation but increased cloud-cover on Monday. Looking ahead, models continue to indicate a fairly robust plume of monsoon-related moisture to begin circulating around the ridge into the Northern Rockies and MT beginning Tuesday and potentially continue across the area through the rest of next week supporting an increased risk for daily shower and thunderstorm activity with afternoon temperatures not as hot due to the increased moisture and cloud- cover. Precipitable Water (PWATs) well in excess of 1.00" are supported by most models/ensembles Tuesday through Thursday of next week, which will bring the risk for heavy rain producing thunderstorms. Hoenisch

- Forecast Confidence & Scenarios:

Below are the probabilities for maximum temperatures reaching or exceeding 100F this weekend: Sat 7/11 Sun 7/12 Great Falls 50% 50% Bozeman 5% 75% Helena 50% 50% Havre 75% 70% Cut Bank 0% 0% Lewistown 10% 80% Dillon 0% 20%

AVIATION

11/12Z TAF Period

Except for an isolated shower in the KHVR vicinity early this morning, mainly clear skies and VFR conditions prevail at all terminals through the TAF period. Surface winds become breezy with a few 20-25kt gusts this afternoon before winds decouple and become generally light again late this evening/overnight. Hoenisch

FIRE WEATHER

Fire weather concerns this weekend are greatest across southwest MT where deeper mixing is expected today and especially on Sunday as the thermal trough shifts across the area. Probabilities for wind gusts in excess of 35 mph are mainly below 30% today but increase to 50% or better for much of southwest MT Sunday afternoon, including areas as far north as the valleys of Broadwater and Meagher counties. The Hot-Dry-Windy Index is projected to exceed the 90th percentile across these areas on Sunday with near record afternoon temperatures and very low humidity leading to elevated fire weather risk. Hoenisch

PRELIMINARY POINT TEMPS/POPS

GTF 100 61 100 62 / 0 0 10 10 CTB 91 58 91 61 / 0 0 0 0 HLN 100 63 100 65 / 0 0 10 0 BZN 98 61 102 60 / 0 0 10 10 WYS 91 49 97 51 / 0 0 0 0 DLN 95 56 98 57 / 0 0 10 0 HVR 102 63 101 63 / 0 0 10 20 LWT 98 59 103 59 / 0 0 10 10

TFX WATCHES/WARNINGS/ADVISORIES

Heat Advisory from noon today to 9 PM MDT Monday for Bears Paw Mountains and Southern Blaine-Canyon Ferry Area-Cascade County below 5000ft-Eastern Pondera and Eastern Teton-Eastern Toole and Liberty-Fergus County below 4500ft-Gallatin Valley-Gates of the Mountains-Helena Valley-Hill County-Judith Basin County and Judith Gap-Madison River Valley-Missouri Headwaters-Northern Blaine County-Southern High Plains-Western and Central Chouteau County.