textproduct: Great Falls

KEY MESSAGES

- Impactful winter weather continues across the region today and tonight.

- Gusty northwest winds continue over the plains today and develop again Friday morning.

- Snow showers Friday afternoon in many areas.

- Overall cooler and unsettled conditions persist this weekend before gradual warming early next week.

UPDATE

/Issued 517 AM MDT Thu Apr 23 2026/

No significant changes were made this morning with the update. The main update this morning was to account for latest trends and increase PoPs slightly over the plains this afternoon. Sufficiently steep lapse rates will allow for snow showers to form in many areas this afternoon where synoptic forcing does not result in a stratiform snow. Consideration was given toward beginning the Winter Weather Advisory for Southwest MT valleys at noon today given anticipated snow shower activity. Confidence in impacts being realized were not high enough to warrant that change, however. Trends will continue to be monitored for any changes in thinking through the day. -AM

DISCUSSION

/Issued 307 AM MDT Thu Apr 23 2026/

- Meteorological Overview:

The initial wave within a conglomerate of upper level shortwaves is passing off to the east early this morning. The second wave diving southward from far southeastern BC is just beginning to move in, which will be the main driver of snow along the Continental Divide and adjacent areas today. At the surface, gusty northwest winds continue over the plains early this morning, with snow levels still falling across the region. Heavy snow is mainly confined to the mountains this morning, but is still expected to develop at least briefly at some lower elevation locations such as in and around the Armington Junction area. The risk for localized brief blizzard conditions near the Little Belts and east of Armington Junction to Geyser will gradually subside through the early morning as winds ease somewhat and snowfall rates decrease. There was some concern for a stronger band of precipitation to back in from the east or northeast associated with a TROWAL, but latest short-term guidance keeps this activity in eastern Montana through the remainder of the night and morning. Gusty winds do look to continue across the plains, mainly east of a Shelby to Lewistown line through the day today, gustiest downstream of terrain.

Attention then quickly turns to the Continental Divide and adjacent areas today into tonight, as the aforementioned wave dropping from BC toward western MT and eventually SW MT moves in. A frontogenetic band of snow looks to develop and slowly drift southward today into tonight along the Continental Divide and into Southwest Montana. Most snow looks rather light, but as the band moves through locally heavier snowfall will develop for a few hours. Impacts from the snow largely look minor at and below passes, though higher elevations in Madison and Gallatin county do look to see continued slightly more impactful snow.

A cold, cyclonic northwesterly flow aloft continues into Friday across the region as many of the aforementioned shortwaves aloft consolidate into a larger upper level low over SK and vicinity. While synoptic snow gradually ends across Southwest Montana and adjacent areas Friday morning, snow showers will become numerous through the afternoon, especially over the plains thanks to steep lapse rates. The combination of these snow showers and gusty winds over the plains brings about a snow squall concern should a more consolidated line develop.

The upper level low gradually drifts back westward this weekend across far southern Canada, continuing to promote cooler and unsettled conditions across the region. It isn't until early next week until this upper level low shows signs that it will exit eastward and allow for temperatures to trend back closer to normal. -AM

AVIATION

23/18Z TAF Period

An area of mid- level frontogenesis is continuing to move southeastward into southwest MT and will introduce periodic IFR/LIFR conditions and snow to KBZN, KEKS, and KWYS. Conditions have improved at KHLN, but there will be additional snow showers that may bring IFR/LIFR categories once again this afternoon. Cold northwesterly flow aloft will send more rounds of low stratus, light to at times moderate snow, and gusty northwesterly winds to all areas tonight into Friday. - RCG

PRELIMINARY POINT TEMPS/POPS

GTF 40 24 39 21 / 70 40 70 30 CTB 41 21 35 19 / 30 30 60 20 HLN 39 23 40 20 / 90 70 50 20 BZN 42 20 39 16 / 90 70 60 10 WYS 41 14 36 11 / 90 70 60 10 DLN 45 22 39 18 / 80 70 50 10 HVR 46 24 36 21 / 10 30 70 40 LWT 38 21 35 18 / 50 10 60 20

TFX WATCHES/WARNINGS/ADVISORIES

High Wind Warning until 6 PM MDT this evening for Bears Paw Mountains and Southern Blaine-Eastern Toole and Liberty-Fergus County below 4500ft-Hill County-Northern Blaine County-Western and Central Chouteau County.

Winter Weather Advisory until 6 PM MDT this evening for East Glacier Park Region.

Winter Weather Advisory until noon MDT Friday for Big Belt, Bridger and Castle Mountains-Elkhorn and Boulder Mountains-Gates of the Mountains-Helena Valley-Northwest Beaverhead County-Ruby Mountains and Southern Beaverhead Mountains-Southern Rocky Mountain Front-Upper Blackfoot and MacDonald Pass.

Winter Storm Warning until 6 PM MDT this evening for Little Belt and Highwood Mountains.

Winter Storm Warning until noon MDT Friday for Gallatin and Madison County Mountains and Centennial Mountains.

Winter Weather Advisory from 6 PM this evening to noon MDT Friday for Beaverhead and Western Madison below 6000ft-Canyon Ferry Area-Gallatin Valley-Madison River Valley-Meagher County Valleys-Missouri Headwaters.