textproduct: Great Falls

KEY MESSAGES

- Rain, freezing rain, snow this morning across much of North Central MT.

- Strong winds possible over portions of North Central MT today and Thursday.

- It will still be mild later today and Thursday morning, before the arctic cold front moves southward Thursday afternoon.

- There is the potential for heavy snow over the eastern portions of North Central MT late Thursday into Friday.

- After a cold start to the weekend, a return to above normal temperatures is expected by early next week.

UPDATE

Morning update has been published, with the main adjustments being to start the High Wind Warning for both the Northern and Southern High Plains adjacent to the Rocky Mountain Front earlier as winds were already gusting between 65 and 75 mph west of the US Hwy 89 corridor. Additionally, the Winter Weather Advisory along the I-15 and US Hwy 89 corridors was cancelled early as surface temperatures and ground temperatures have warmed above freezing, which has brought and end to the threat for freezing rain. Otherwise the remainder of the forecast remains on track. - Moldan

DISCUSSION

/Issued 438 AM MST Wed Dec 10 2025/

- Meteorological Overview: A moist westerly flow aloft continues over MT this morning. (This current moisture plume aloft is very high, and is being referred to as an atmospheric river of moisture...with the origins of this moisture plume in the Pacific near Hawaii.) The end result is a wave of moisture will move eastward over MT this morning. There is quite a bit of warm air also moving in from the west, thus snow levels are rather high, generally above 5500 feet. That being said, current air temperatures are in the mid 30s, while surface pavement temperatures are in the upper 20s and lower 30s. Thus the precipitation is likely to fall as rain at lower elevations, but with pavement temperatures still about 10 degrees colder than air temperatures, some of the rain will freeze this morning on pavement surfaces. Thus a widespread winter weather advisory was issued for North Central MT for this morning. Otherwise some accumulating snow is likely in the mountains above 5500 feet this morning, especially over North Central MT.

The other concern today is the high wind potential. Strong winds look on track for the Browning, Choteau and Cut Bank areas, thus no changes there. However, there is the potential for strong winds over MacDonald Pass and across the lower elevations of Judith Basin County. Thus the high wind warning was expanded to cover those areas. For Judith Basin, it is likely that the strong winds will continue into Thursday, thus the high wind warning will last a bit longer for that zone.

Warmer air slowly moves in later today and will be here through Thursday morning. On Thursday afternoon, the arctic cold front is once again forecast to move back southward through North Central MT. The arctic boundary will likely not make it southward through our entire CWA. Currently it is progged to stall along a line from about Boulder to Bozeman on Friday morning, before starting to move back northward on Friday afternoon. A band of heavy snow is likely along the frontal passage on Thursday afternoon/evening, with the potential for heavy snow developing by Friday morning over North Central MT. Thus the winter storm watch for Thu/Fri will continue.

Over the weekend, the cold air is expected to retreat northward, and go back into Canada either late Sat or Sun. The timing of this will have an impact on high temperatures Sat over the north.

For early next week, warmer air is forecast to move back into the CWA, with much above normal temperatures for the first half of next week. Additionally, there is another potential for strong winds over North Central MT on Tue/Wed.

- Forecast Confidence & Scenarios: There is a 70 percent chance for high winds today in the Cut Bank, Browning and Stanford areas. There is a 60 percent of high winds for areas near/south of Great Falls today as well. Thus the high wind warning could be expanded a bit later today should the high winds develop across portions of Cascade County.

For Thursday, there is near an 80 percent chance for high winds in Judith Basin County, while there is a 60 percent chance for high winds near and west of Great Falls.

For the winter storm watch...the main concern will be how far south the cold front goes and how much lift do we get on the cold side on Friday to create the potential for heavy snow over North Central MT. Where the cold front stalls on Friday will greatly determine where the heavy snow sets up on Friday. Should the front stall a bit further north, the area of heavy snow will likely shift northward a bit into southern Canada. Should the front make it all the way south to I-90, then it is likely that much of North Central MT could get some heavy snow on Friday. Overall, the forecast models continue to show the potential for about a 5 to 12 inch snowfall in the band of heavy snow that sets up on Friday.

Additionally, there is the potential for some cold weather advisory statements Friday into Saturday over the northern portions of North Central MT. Brusda

AVIATION

10/12Z TAF Period

Main concern before 18z today will be the potential for freezing rain over North Central MT. For the Helena/Great Falls area, it is above freezing, but pavement surfaces are below freezing. Other areas such as LWT and HVR have temps below freezing, thus straight freezing rain is possible. There is the potential the freezing rain could last a bit longer into the afternoon over the eastern portions of the CWA. Otherwise, expect windy conditions to develop over the western portions of the CWA this morning and then continue into this evening. After 00z Thu, expect rain/snow to develop along the Highway 2 corridor from Cut Bank to Havre. Mountains/passes will be obscured across the CWA throughout the period at times. Brusda

PRELIMINARY POINT TEMPS/POPS

GTF 55 46 54 9 / 60 30 90 60 CTB 48 26 42 -1 / 30 50 70 40 HLN 55 45 53 27 / 70 30 60 70 BZN 53 40 54 35 / 60 10 30 60 WYS 40 29 39 29 / 80 10 30 50 DLN 54 38 52 40 / 30 0 10 20 HVR 46 26 38 -4 / 80 80 80 50 LWT 49 39 49 9 / 90 40 80 70

TFX WATCHES/WARNINGS/ADVISORIES

Winter Weather Advisory until 11 AM MST this morning for Bears Paw Mountains and Southern Blaine-East Glacier Park Region- Eastern Toole and Liberty-Fergus County below 4500ft-Helena Valley-Hill County-Judith Basin County and Judith Gap-Little Belt and Highwood Mountains-Northern Blaine County-Snowy and Judith Mountains-Southern Rocky Mountain Front-Upper Blackfoot and MacDonald Pass-Western and Central Chouteau County.

High Wind Warning until 8 PM MST this evening for Northern High Plains-Southern High Plains.

Winter Storm Watch from Thursday morning through late Friday night for Bears Paw Mountains and Southern Blaine-Eastern Glacier, Western Toole, and Central Pondera-Eastern Toole and Liberty-Hill County-Northern Blaine County.

Winter Storm Watch from Thursday afternoon through late Friday night for Cascade County below 5000ft-East Glacier Park Region- Eastern Pondera and Eastern Teton-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-Southern Rocky Mountain Front-Western and Central Chouteau County.

High Wind Warning until 8 PM MST this evening for Eastern Glacier, Western Toole, and Central Pondera-Upper Blackfoot and MacDonald Pass.

High Wind Warning until 3 PM MST Thursday for Judith Basin County and Judith Gap.