textproduct: Great Falls

KEY MESSAGES

- It will be windy across North-central, Central, and Southwestern Montana on Friday.

- It will cool off through this weekend with showers and thunderstorms Friday through Sunday.

UPDATE

Updated forecast is out. The threat for severe thunderstorms has ended for our CWA for tonight. Additionally, the high wind warning for the Ennis/Norris Hill area has also ended.

Just a few showers/thunderstorms remain this evening, as the precipitation rotates around the upper level low. This upper level low will remain to our west going into the weekend, allowing for scattered showers/thunderstorms to continue over the next few days. Current forecast is on track for overnight lows. Brusda

DISCUSSION

/Issued 200 PM MDT Wed Sep 2 2026/

- Meteorological Overview:

This afternoon there is an an upper-level trough moving over North- central, Central, and Southwestern Montana. This will allow temperatures to cool down slightly with showers and thunderstorms across the area. Due to strong southerly flow aloft and strong low- level winds it will be windy across North-central, Central, and Southwestern Montana on Wednesday with the strongest winds along the Rocky Mountain Front and in north-south orientated valleys. On Thursday the upper-level trough remains over North-central, Central, and Southwestern Montana. This combined with strong southerly flow aloft and strong low-level winds will bring another day of windy conditions to the area. On Thursday it will be mostly dry.

On Friday a closed upper-level low is over Washington and Oregon with southwest flow over North-central, Central, and Southwestern Montana. This will allow temperatures to be around seasonal averages with another day of showers and thunderstorms and breezy conditions. On Saturday and Sunday the closed upper-level low remains over Washington and Oregon with southwest flow over North- central, Central, and Southwestern Montana. This will bring another day with about seasonal averages for temperatures and showers and thunderstorms around each day this weekend. -IG

- Forecast Confidence & Scenarios:

On Friday there is a 40 - 80% chance for wind gusts of 30 mph or greater across North-central, Central, and Southwestern Montana with the greatest probability in Southwestern Montana.

On Saturday there is a 15 - 30% chance for thunderstorms across Central and Southwestern Montana. On Sunday there is a 15 - 30% chance for thunderstorms across North-central, Central, and Southwestern Montana. -IG

Fire Weather: Medium Confidence (50%) in critical conditions on Thursday. Winds are the highest source of confidence, humidity is our lowest with values borderline. However, deep mixing advertised by the models does support values approaching critical values.

Extended Regime: Low Confidence (30%) in the overall changes in the upper-level pattern. Cut off lows are notoriously difficult to pin point in the long range as are the resulting impacts.

AVIATION

03/00z TAF Period

Terminal KHVR has a low probability of -TSRA through 02z as out primary system exits northeast. High confidence in VFR conditions across all terminals as remnant thunderstorms continue to progress northeast out of the region. Surface winds will largely calm down through the night, with southwest Terminal KWYS, KEKS, and KBZN remaining breezy above 10kts. Winds ramp back up across all terminals moving into Thursday afternoon as our shortwave progresses across Montana. Isolated light showers across southwest Montana Thursday morning. Low confidence in these across terminal KEKS, with higher confidence in KWYS. If these storms were to impact the terminal, expected lowered ceilings and erratic gusty winds.

For KGTF: Gusty winds will continue through at least 03/04Z before slowly tapering off as the night continues. The threat for crosswinds will be low but the headwinds may be above 15kts through at least 03/05Z. Winds will again ramp up 03/17z. For a brief period between 17z and 20z probability of cross winds meeting the 15kt threshold is 20% before winds solidly shift from the southwest with low probability of cross winds exceeding the 15kt threshold for the remainder of the TAF period. -JR

PRELIMINARY POINT TEMPS/POPS

GTF 50 76 49 74 / 10 0 10 10 CTB 46 66 45 66 / 40 0 30 10 HLN 46 75 47 74 / 10 0 10 30 BZN 47 76 45 79 / 0 0 0 0 WYS 33 64 36 68 / 0 0 0 0 DLN 42 72 41 74 / 10 0 10 20 HVR 50 80 51 81 / 30 0 0 0 LWT 49 77 52 80 / 10 0 0 0

TFX WATCHES/WARNINGS/ADVISORIES

Red Flag Warning for portions of Southwest MT.