textproduct: Great Falls

KEY MESSAGES

- Warm, dry, and windy conditions tomorrow bring elevated to critical fire weather conditions to portions of the area. - Briefly cooler behind a cold front tomorrow evening, then temperatures warm again for the weekend. - Some unsettled weather is possible early to middle of next week.

DISCUSSION

/Issued 259 PM MDT Tue Mar 24 2026/

Weak upper ridging currently over the western US will begin to break down on Wednesday as an upper level trough and attendant surface cold front push into the area late Wednesday and early Thursday. As this trough approaches, expect winds to increase across the area, particularly along the Hi Line and across Southwestern Montana. Southwestern Montana will be of particular interest tomorrow, as the winds will combine with warm temperatures, low humidity, and dry fine fuels to produce elevated to fire weather conditions, which has prompted a Red Flag Warning, which will be discussed further in the confidence and scenarios section and the Fire Weather Section.

Behind the cold front, expect a brief period of some mountain precipitation, with light snow over a few of the higher passes. Any snow accumulations, however, will be light and gradual, so for now we will just message this snowfall here and via other public channels without resorting to a Winter Weather Advisory, at least for now. After this snow, however, upper level ridging will gradually build back into the area, bringing a return to warm and dry weather for the weekend.

As we look towards next week, another weather system will look to push through the area, bringing a period of cooler and wetter weather sometime during the first half of the work week.

- Forecast Confidence & Scenarios:

Winds and Fire Weather Wednesday: Gusty winds are expected along the Hi Line and across far Southwestern Montana tomorrow as a cold front approaches the area. While current probabilistic guidance (and at least to some degree the raw model output as well) is a bit less bullish on the winds tomorrow than it had been 24 hours, strong wind gusts over 58 mph still look to be likely along the US 2 corridor (especially closer to the Rocky Mountain Front) where the proximity to the cold front will help accelerate the winds in the late morning and afternoon. Further south, I am less confident in winds reaching High Wind Warning Criteria over a widespread area, but elected to keep the High Wind Warning in place partly as a messaging tool in conjunction with Red Flag Warning that has been issued for much of Southwestern Montana. With respect to fire weather, the strong winds will combine with RH values dipping into the upper teens to create critical fire weather conditions, which will assist any fires that start tomorrow to grow and spread quickly if they get into the right fuels. Ludwig

AVIATION

25/00Z TAF Period.

The primary concern this TAF period will be for gusty winds developing through the night and into the day Wednesday. An initial mountain wave activity concern transitions to be a low- level turbulence concern by late Wednesday morning into the afternoon across much of the region.

Light precipitation crossing the Continental Divide will result in some instances of mainly virga with a few isolated instances of precipitation making it to the surface. That said, VFR conditions look to prevail even around any precipitation.

A few instances of low-level wind shear will be around tonight in areas where surface winds go light/variable. These instances look to be too isolated/brief to warrant mention in any TAF at this time. -AM

FIRE WEATHER

Warm, dry, and breezy conditions are expected area wide tomorrow, with the strongest winds likely to be found along the US 2 Corridor and a second maxima across Southwestern Montana. Southwestern Montana will see RH values dipping into the upper teens as temperatures climb into the mid to upper 60s. Winds will weaken after sunset, but a cold front will push through the area from the north during the evening and overnight hours, bringing a wind shift to the north. Some light precipitation is expected, mainly over the higher terrain with this frontal passage, but is not expected to produce much moisture on the fine fuels across the plains. Ludwig

PRELIMINARY POINT TEMPS/POPS

GTF 48 63 29 46 / 20 10 20 10 CTB 41 53 18 39 / 30 0 20 20 HLN 44 65 29 46 / 40 30 30 10 BZN 44 72 31 49 / 30 10 50 20 WYS 36 61 29 47 / 10 10 20 20 DLN 43 69 32 49 / 20 10 10 0 HVR 42 63 22 39 / 40 10 10 20 LWT 44 64 28 42 / 30 30 60 30

TFX WATCHES/WARNINGS/ADVISORIES

High Wind Warning from 3 AM to 6 PM MDT Wednesday for Eastern Glacier, Western Toole, and Central Pondera-Eastern Toole and Liberty.

High Wind Warning from 9 AM to 7 PM MDT Wednesday for Beaverhead and Western Madison below 6000ft-Big Belt, Bridger and Castle Mountains-Gallatin Valley-Gallatin and Madison County Mountains and Centennial Mountains-Hill County-Madison River Valley- Missouri Headwaters-Northern Blaine County-Ruby Mountains and Southern Beaverhead Mountains.

Red Flag Warning from noon to 7 PM MDT Wednesday for Helena and Townsend Ranger Districts of the Helena National Forest.