textproduct: Great Falls

KEY MESSAGES

- Hot temperatures through Saturday before a cooldown Sunday through the first half of next week.

- Hot, dry, and windy conditions Saturday and Sunday bring critical weather conditions across the region.

- Wildfire smoke continues to impact the region through the end of the week.

- Dry conditions settle in into next week.

DISCUSSION

/Issued 412 AM MDT Fri Jul 31 2026/

- Meteorological Overview:

The upper-level ridge pattern continues Friday which will bring another day of hot temperatures to the region. Drier PWATs and little forcing Friday will keep most of the region dry, but I can't rule out a few showers and thunderstorms in Southwest MT during the afternoon. Temperatures peak on Saturday as the ridge breakdowns and southwest flow increases. Lower elevations are forecasted to reach into the 100s across north-Central MT and the upper 90s in Southwest MT. The ridge breakdown also brings an increase in 700mb winds through Sunday, peaking late Saturday night into early Sunday morning to 60-70kts along the Northern Rocky Mountain Front. As a result, strong winds develop along the Rocky Mountain Front windy conditions develop elsewhere Saturday and Sunday. This with the combination of hot temperatures and low relative humidity creates concerns for elevated to critical fire weather conditions (see FIRE WEATHER section).

A mostly dry frontal passage Sunday will help bring a relief in the heat through the first half of next week. Northwest flow aloft will help keep temperatures down through Tuesday, before very warm temperatures return. Low moisture throughout the week will keep conditions dry.

- Forecast Confidence & Scenarios:

Heat this Weekend:

There remains good confidence in impactful heat setting up Saturday across the region, especially North-Central MT. Based on recent temperature trends this week with the wildfire smoke, the NBM may be running up to few degrees too hot for Saturday. However, there is good confidence for widespread temperatures in the 100s across North- Central MT Saturday. Therefore, the current heat products remain on track.

Winds Saturday and Sunday:

Models have been consistent on the increase in winds and the timing of peak winds. There is a 30-60% chance for 60 mph winds along the immediate eastern slopes of the Rocky Mountain Front. Although this is a typically windy region, it will be unusually windy for the time of year, as wind gusts exceed the 95th percentile for August. Therefore, these wind speeds are more impactful for the time of year. The main impact will be for outdoor recreation, particularly for Glacier NP and those traveling in high profile vehicles. -Wilson

AVIATION

31/18Z TAF Period

Main concern this TAF period will be wildfire smoke reducing slant- range visibility across the region. A few showers and thunderstorms look to develop near the Idaho border this afternoon, though coverage continues to look too low to warrant a mention in the KWYS TAF. Density issues may develop during the peak of the afternoon heat today and again on Saturday as temperatures at most lower elevation terminals (all but KWYS) get close to or over 100F.

For KGTF: Diurnal mixing will result in a west to northwest wind this afternoon and early evening. The overall magnitude of wind looks to be 10 kts or less, yielding a low probability for cross winds of 15+ kts. -AM/Ludwig

FIRE WEATHER

Elevated to critical fire weather conditions is expected Saturday afternoon through Sunday evening across North-Central, Central, and Southwest Montana. On Saturday, hot temperatures in the upper 90s to near 108 degrees will combine with minimum RH values as low as 8% and frequent gusts of 25 to 40 mph with gusts up to 50 mph. Higher gusts are expected along the Rocky Mountain Front to create the potential for critical fire weather conditions. Sunday will be cooler but low RH values and stronger winds than Saturday are still expected which will still pose a significant concern not only for ongoing fires but any potential new starts that occur. A Fire Weather Watch remains in effect from Saturday afternoon through Sunday evening across all of North-Central, Central, and Southwest Montana. -thor/Wilson

PRELIMINARY POINT TEMPS/POPS

GTF 60 102 61 86 / 0 0 0 0 CTB 54 97 54 76 / 0 0 0 0 HLN 60 100 60 85 / 0 0 0 0 BZN 57 100 57 91 / 0 0 0 0 WYS 47 91 48 87 / 0 0 0 0 DLN 55 94 54 88 / 0 0 0 0 HVR 57 105 61 86 / 0 0 0 0 LWT 58 100 59 86 / 0 0 0 0

TFX WATCHES/WARNINGS/ADVISORIES

Heat Advisory from noon Saturday to 3 AM 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-Elkhorn and Boulder Mountains-Gates of the Mountains-Helena Valley-Hill County-Meagher County Valleys-Missouri Headwaters-Northern Blaine County-Snowy and Judith Mountains.

Red Flag Warning from 2 PM Saturday to 9 PM MDT Sunday for Central and Eastern Lewis and Clark National Forest Areas- Chouteau and Fergus Counties-Eastern Glacier/Toole/Central/Eastern Pondera/Liberty-Helena and Townsend Ranger Districts of the Helena National Forest-Hill and Blaine Counties-Lewis and Clark National Forest Rocky Mountain District-Rocky Mountain Front-Lincoln Ranger District of the Helena National Forest.

High Wind Warning from 6 PM Saturday to noon MDT Sunday for East Glacier Park Region-Eastern Glacier, Western Toole, and Central Pondera-Northern High Plains.

Extreme Heat Warning from noon Saturday to noon MDT Sunday for Bears Paw Mountains and Southern Blaine-Fergus County below 4500ft-Western and Central Chouteau County.

Extreme Heat Warning from noon Saturday to 3 AM MDT Sunday for Cascade County below 5000ft-Gallatin Valley-Judith Basin County and Judith Gap-Madison River Valley.