textproduct: Great Falls

KEY MESSAGES

- Dangerously hot temperatures continue through the weekend, with heat peaking on today. - Isolated thunderstorms today are expected across Central Montana, some of which may produce strong outflow winds and very little rainfall. - Heat lessens slightly next week, but temperatures still remain warm.

DISCUSSION

/Issued 201 PM MDT Sat Jul 25 2026/

- Meteorological Overview:

Upper level ridging will continue to be the dominant weather feature of our weather over the upcoming week, keeping us generally warm and dry save for a few opportunities for afternoon thunderstorms. Heat will continue to be the most widespread hazard through the weekend as the ridge remains positioned in a way that keeps us in southwesterly flow aloft. This heat will peak on today, even as a shortwave moving over Washington will kick off a few afternoon showers and thunderstorms. More details on the heat and thunderstorms can be found below in the Confidence and Scenarios sections.

Temperatures will lessen slightly Sunday as the ridge wanes slightly, but temperatures will remain hot with most lower elevations reaching the mid 90s to near 100. Temperatures will wane slightly further Monday as the ridge continues to wane a bit, but by Monday the ridge will settle into a state it will more or less maintain its strength through the remainder of the week. The main day to day difference will be a few rounds of monsoonal moisture working through the area, which may allow for afternoon thunderstorms to pop up. As of now, the best chances for afternoon thunderstorms outside of today will be after Wednesday, but I would not rule out a storm popping up any day over the next week.

- Forecast Confidence & Scenarios:

Heat through Sunday: The ongoing heat wave will continue through Sunday as the upper level ridge maintains its strength. The main question will be just how hot does it get during the day, and to what degree does it cool off overnight. Raw model output seems to be fairly consistent at keeping lower elevation locations across the plains near 100-107today, and upper 90s to near 100 on Sunday. However, there are a few areas of uncertainty. While smoke remains a source of some uncertainty, the impact from the smoke appears to have been rather muted the past 24 hours or so. The other, more significant wild card for today will be afternoon convection, which would quickly cool off any areas that see thunderstorms and/or their outflows, which may keep them from reaching their true temperature potential provided the storms move through before mid to late afternoon.

Thunderstorms today: Convective models continue to show a robust round of showers and thunderstorms across Southwestern and Central Montana this afternoon and evening. While an area of light showers/thunderstorms did manage to move through Jefferson, Broadwater, and Meagher Counties, satellite shows that a more robust area of convective initiation appears to be underway across Southwestern Montana and Eastern Idaho as of 1PM. Given the very warm and dry environment, any thunderstorm is liable to produce little rainfall on the ground, and may also produce strong outflows. Storms will also have just enough shear to get organized, and dry air aloft may help promote processes that produce downburst winds and their associated outflows. Ludwig

AVIATION

26/00Z TAF Period

Showers and thunderstorms capable of strong and erratic wind gusts will continue to progress northeastward across Central and Southwest Montana, finally exiting or diminishing after 04Z. Another round of showers and thunderstorms develops again Sunday afternoon, mostly across Southwest Montana. -AM

FIRE WEATHER

A Red Flag Warning remains in effect across portions of North- Central Montana today with widespread minimum RH values below 20%, frequent gusts up to 30 to 40 mph, and hot temperatures expected. Additionally, isolated thunderstorms may produce localized strong wind gusts and cloud to ground lightning, along with very little rainfall. The concern will be that any fire that starts may be very difficult to contain. Those who are doing anything that could generate sparks, including yard work, farming, towing trailers, or other activities should do everything possible to prevent a spark while traveling and/or recreating outdoors.

Marginal to elevated fire weather concerns may extend into Sunday and Monday as well, though lesser wind speeds and lower temperatures give lower confidence for critical fire weather conditions at the moment. Ludwig/Wilson

PRELIMINARY POINT TEMPS/POPS

GTF 61 97 60 94 / 20 0 0 0 CTB 59 89 55 89 / 0 0 0 0 HLN 60 95 60 93 / 30 0 10 0 BZN 61 95 58 94 / 40 10 20 10 WYS 50 87 50 86 / 20 20 10 10 DLN 56 91 55 90 / 30 20 10 0 HVR 63 98 60 97 / 30 0 0 0 LWT 60 94 58 91 / 40 0 10 0

TFX WATCHES/WARNINGS/ADVISORIES

Red Flag Warning until 9 PM MDT this evening for Central and Eastern Lewis and Clark National Forest Areas-Chouteau and Fergus Counties-Eastern Glacier/Toole/Central/Eastern Pondera/Liberty-Hill and Blaine Counties-Lewis and Clark National Forest Rocky Mountain District-Rocky Mountain Front.

Heat Advisory until 9 PM MDT Sunday for Beaverhead and Western Madison below 6000ft-Canyon Ferry Area-Eastern Glacier, Western Toole, and Central Pondera-Eastern Pondera and Eastern Teton- Eastern Toole and Liberty-Gallatin Valley-Gates of the Mountains- Helena Valley-Madison River Valley-Meagher County Valleys- Missouri Headwaters.

Extreme Heat Warning until 9 PM MDT Sunday for Bears Paw Mountains and Southern Blaine-Fergus County below 4500ft.

Heat Advisory from midnight tonight to 9 PM MDT Sunday for Cascade County below 5000ft-Hill County-Judith Basin County and Judith Gap-Northern Blaine County-Western and Central Chouteau County.

Extreme Heat Warning until midnight MDT tonight for Cascade County below 5000ft-Hill County-Judith Basin County and Judith Gap-Northern Blaine County-Western and Central Chouteau County.