textproduct: Great Falls

KEY MESSAGES

- A long duration strong wind event impacts areas along the Rocky Mountain Front beginning tonight and expands to all of north-central and southwest Montana Thursday morning.

- Snow intensifies along the Continental Divide tonight with moderate to heavy snow and strong winds creating blizzard conditions for a period from late tonight through Thursday morning from Rogers Pass north to Marias Pass.

- Winter weather impacts increase across north-central and central Montana Thursday night through Saturday as areas of snow become more widespread.

UPDATE

/Issued 706 PM MDT Wed Mar 11 2026/

Current forecast looks to remain on track this evening. Road temperatures have dropped to freezing and snow have started to accumulate on the pavements along U.S 2. The main 700mb jet is in WA/ID, but the 700mb front is in Western MT. Winds will pick up in the next few hours as the better winds aloft move in. Heavy snow will begin along the Continental Divide as the upper- level front moves through. Timing for the most impactful blizzard conditions looks to be on track between 12am-8am Thursday for the Northern Continental Divide. -Wilson

DISCUSSION

/Issued 706 PM MDT Wed Mar 11 2026/

- Meteorological Overview:

A strong westerly mid-upper level jet is approaching the Pacific NW coast this afternoon, sandwiched between a usually deep trough in the Gulf of AK and strong upper level ridging centered off the coast of CA. A fairly robust plume of atmospheric moisture is also embedded within the strong flow, which will produce multiple wind and winter weather impacts as this zone of strong winds and moisture stream across the Northern Rockies and MT over the next several days.

Expect the onset of strong winds along the Rocky Mtn Front by midnight tonight before expanding east across the remainder of the area by Thursday morning as the initial wave ejecting out from the Pacific tracks east along the US/Canadian border. Surface low pressure tracks east across southern AB/SK with a WSW-ENE Pacific frontal boundary sagging south through central MT by Thursday afternoon. Meanwhile, orographically forced snow already along northern portions of the Continental divide will increase tonight the arrival of the Pacific frontal system and deeper moisture plume. This in tandem with the increasing winds will support an increasing coverage of snow and blowing snow along the divide as far south as MacDonald Pass by late tonight and into the Pintler/Beaverhead Ranges by Thursday morning. Showers tracking east of the continental divide with the initial frontal passage on Saturday will be less numerous but enough enough atmospheric instability will be present for some brief/but intense showers which may begin as rain with a transition to graupel or snow showers.

Winds decrease late Thursday through Thursday night as the mid-upper level wind maximum moves off to the east and a secondary Canadian frontal boundary sags south across north-central MT, shifting winds to the north and bringing a cooler airmass southward across the plains. This E-W frontal zone stalls across central MT Friday through Saturday and serves as a focus for precipitation as the Pacific moisture plume continues to stream overhead. Snow within this frontal zone becomes more widespread with greater intensity late Friday through Saturday as an embedded shortwave disturbance moves across the region.

The cooler airmass and areas of snow may linger into Sunday before upper level ridging amplifies off the west coast and shifts inland next week, bringing much warmer and drier conditions by the middle of next week. Hoenisch

- Forecast Confidence & Scenarios:

Strong Wind Hazards:

Confidence remains high in a widespread and long duration wind event to impact all of north-central and southwest MT as an unusually strong (80-90kt @700MB) wind maximum streaks across the northern Rockies and MT later tonight through Thursday. Timing of the strongest winds still looks to be late tonight/early Thursday morning for areas immediately adjacent to the Rocky Mtn Front and during the morning hours across most of north-cetral and southwest MT with strong winds lingering into early Thursday afternoon across eastern portions of north-central and southwest MT. Probabilities for gusts in excess of 55 mph are 80-100% for the entire forecast area with a risk for gusts in excess of 75 mph across some areas not typically associated with winds of this magnitude, including a 60- 75% probability from Cascade and Judith Basin counties south through Meagher and Northern Gallatin counties, where timing of the frontal passage and potential for early afternoon mixing will be most favorable to transport higher winds to the surface. We continue to highlight the longer duration of strong winds (6+ hrs of >55mph gusts) as a factor that can increase the risk for wind damage and power outages as has been seen in other recent wind events.

Winter Weather Hazards:

Blizzard conditions are expected to develop tonight near the continental divide from Glacier NP to as far south as Rogers Pass as the higher intensity snowfall rates and stronger winds develop. Further south along the divide, snowfall amounts decrease, but periods of more intense snow and winds could create localized periods of blowing snow with visibility 1/2 mile or less from MacDonald Pass south through NW Beaverhead county.

Areas adjacent to the East Glacier Region and Rocky Mtn front may see some minor snow accumulations as snow showers move off the continental divide following the cold front Thursday morning. The combination of very strong winds (gusts in excess of 70mph), some fresh snowfall and downstream wind transport of snow from areas to the west, could also produce reduced visibility in blowing snow, though not to the extent as areas further west.

A Winter Storm Watch continues for much of north-central and central MT for the Thursday night through Saturday afternoon period. Confidence is high in a multi-day period of snowfall affecting these areas with the focus for more impactful snow amounts shifted some towards late Friday into Saturday. Hoenisch

AVIATION

12/06z TAF Period

Winds will begin to increase overnight region wide, with winds peaking Thursday morning (between 13/12z-13/18z). Before winds pick up, low level wind shear will be a concern. Winds will likely be the strongest over the North-Central MT plains, where they could peak between 55-65kts. Precipitation will come off of the Continental Divide Thursday morning/afternoon and will bring light rain/snow showers to lower elevations. A cold front will help decrease winds Thursday afternoon/evening. This front will stall out across North-Central MT late Thursday night. There is a little uncertainty in precipitation timing for terminals due to differences in front timing/if showers overcome the dry surface air. -Wilson

PRELIMINARY POINT TEMPS/POPS

GTF 37 47 26 29 / 20 40 70 90 CTB 28 39 19 27 / 60 30 70 80 HLN 37 47 30 39 / 80 90 90 100 BZN 35 53 32 49 / 10 30 50 60 WYS 26 45 31 44 / 50 40 50 80 DLN 34 52 36 54 / 30 30 20 30 HVR 31 45 20 33 / 50 50 50 40 LWT 31 45 22 31 / 20 70 100 100

TFX WATCHES/WARNINGS/ADVISORIES

Blizzard Warning until 3 PM MDT Thursday for East Glacier Park Region-Southern Rocky Mountain Front.

Winter Weather Advisory from 3 AM to 3 PM MDT Thursday for Northern High Plains-Southern High Plains.

Winter Storm Warning from 3 PM Thursday to 6 PM MDT Saturday for East Glacier Park Region-Southern Rocky Mountain Front.

Winter Storm Watch from Thursday evening through Saturday afternoon for Bears Paw Mountains and Southern Blaine-Cascade County below 5000ft-Eastern Glacier, Western Toole, and Central Pondera-Eastern Pondera and Eastern Teton-Eastern Toole and Liberty-Fergus County below 4500ft-Judith Basin County and Judith Gap-Little Belt and Highwood Mountains-Northern High Plains-Snowy and Judith Mountains-Southern High Plains-Western and Central Chouteau County.

High Wind Warning until 6 PM MDT Thursday for Beaverhead and Western Madison below 6000ft-Big Belt, Bridger and Castle Mountains-Canyon Ferry Area-Cascade County below 5000ft-Eastern Pondera and Eastern Teton-Eastern Toole and Liberty-Elkhorn and Boulder Mountains-Gallatin Valley-Gallatin and Madison County Mountains and Centennial Mountains-Gates of the Mountains-Helena Valley-Judith Basin County and Judith Gap-Little Belt and Highwood Mountains-Madison River Valley-Meagher County Valleys- Missouri Headwaters-Northwest Beaverhead County-Ruby Mountains and Southern Beaverhead Mountains-Upper Blackfoot and MacDonald Pass-Western and Central Chouteau County.

Winter Storm Warning until noon MDT Friday for Northwest Beaverhead County-Upper Blackfoot and MacDonald Pass.

High Wind Warning until 3 PM MDT Thursday for East Glacier Park Region-Eastern Glacier, Western Toole, and Central Pondera- Northern High Plains-Southern High Plains-Southern Rocky Mountain Front.

High Wind Warning from 3 AM to 6 PM MDT Thursday for Bears Paw Mountains and Southern Blaine-Fergus County below 4500ft-Hill County-Northern Blaine County-Snowy and Judith Mountains.