textproduct: Great Falls

KEY MESSAGES

- Increasing chances for rain and snow over Southwest MT tonight, along with fog developing in the Havre and Harlem areas.

- Scattered rain or snow showers will continue for the next few days, with most of the precipitation over the western and southwestern mountains.

- Afternoon temperatures will continue to be above normal for the next several days, with a cooler day possible by next Thursday.

UPDATE

Patchy freezing fog will continue across the Hi-Line through the night into the late morning hours. Right now, visibilities in general have oscillated between 3 miles and 6-8 miles. The two limiting factors are the low stratus deck and the wind which is currently sustained at 15 to 18 mph in Havre. The winds are expected to subside around 3 to 4 AM, and once the winds are calm, there is a chance the visibility could crash a bit temporarily. But there is low confidence in reaching full Dense Fog Advisory criteria. So for now, no headlines will be issued. The main impacts to watch out for will be slippery roads and sidewalks in the morning across northern Chouteau, Hill, and northern Blaine counties.

Precipitation is continuing to make its way north and will primarily impact southwest Montana and the southern Rocky Mountain Front through the late morning hours. Snow totals have not changed since the last forecast and storm total snowfall amounts are not high enough to warrant an advisory at this point in time. There is a concern for some light mixed precipitation at lower elevations but precipitation amounts are expected to be so low that impacts are generally going to be minimal across southwest and central Montana.

Otherwise no changes were made to the going forecast. -thor

DISCUSSION

/Issued 458 PM MST Thu Jan 1 2026/

- Meteorological Overview: An upper level disturbance is moving northward from Idaho into Southwest MT this afternoon. Clouds have increased over the area, as light rain/snow moves northward from Idaho into far Southwest MT. Expect the light precipitation to overspread Southwest MT overnight, with most of the precipitation falling in the mountains. The trend of mountain showers will continue for the next several days, again with Southwest MT and the Rocky Mountain front the favored areas. Overall, the precipitation will be on the light side most days.

Low clouds and fog will continue to move into North Central MT from the east. Overall, the fog should not be as dense as in our CWA as it is closer to Glasgow, so no dense fog advisory will be issued at this time.

Additionally, expect surface winds to increase a bit each day through Tuesday, with Tuesday looking to be the day of the strongest winds. It is also possible that high wind statements might be needed for portions of North Central MT for early next week.

Overall temperatures will generally run above normal for most areas until the middle of next week. Both the GFS/EC want to a swing a trof through the CWA by next Thursday. At this time, it looking like the trof will move through quickly, limiting the snowfall accumulations a bit and how cold it will get.

- Forecast Confidence & Scenarios: Snowfall tonight of around an inch is likely on the roadways from West Yellowstone to Big Sky, with up to 3 inches in the mountains in this areas. For now, no winter winter advisory will be issued at this time, but it will be reconsidered throughout the evening. Brusda

AVIATION

02/00Z TAF Period

A wave of mountain snow and lower elevation rain/wintry mix will lift north throughout the evening and night. Most of the precipitation will remain at higher elevations while lower elevations battle dry air. However, there is a slight chance precipitation reaches down to the lower elevations tonight through Friday morning. Fog and low clouds have developed at KHVR recently, and forecasts soundings depict fog/low clouds staying around through Friday morning. There remains a little uncertainty in how dense the fog becomes, but low clouds will keep mostly LIFR conditions through the night. The other uncertainty is if freezing drizzle makes it to the surface at KCTB overnight. High uncertainty left the mention out of the TAF since drier air will make it difficult for precipitation to reach the ground. -Wilson

PRELIMINARY POINT TEMPS/POPS

GTF 34 54 34 52 / 50 20 0 0 CTB 25 48 20 42 / 30 10 0 0 HLN 31 46 30 48 / 50 20 0 0 BZN 29 48 28 48 / 60 40 0 0 WYS 24 35 26 39 / 90 70 30 20 DLN 32 46 29 46 / 60 20 0 0 HVR 16 32 16 31 / 10 10 0 0 LWT 30 54 31 52 / 20 10 0 0

TFX WATCHES/WARNINGS/ADVISORIES

None.