textproduct: Great Falls

KEY MESSAGES

- Fog looks to develop tonight along and northeast of a Lewistown, to Great Falls, to Cut Bank line, especially within the Milk River Valley of Hill and Blaine Counties.

- Overall dry conditions are expected this weekend, but a few showers can't be ruled out over the plains and mountains of Central and North Central Montana Saturday night and Sunday as a weak front moves south.

- Windy conditions look to return on Tuesday.

UPDATE

A few showers across Central and North-central Montana will diminish with loss of daytime heating this evening. The main concern then turns to development of fog tonight and into Saturday morning. No mentionable changes were needed this evening with the update. -AM

DISCUSSION

/Issued 543 PM MDT Fri Apr 3 2026/

- Meteorological Overview:

Upper level trough and associated closed low responsible for widespread precipitation across the Northern Rockies yesterday and today will lift northeast and over the Upper Mississippi River Valley through tonight, with quasi-northwest flow remaining in place over Southwest through North Central Montana. Skies beneath this dry, northwest flow aloft will clear through the evening hours tonight, which combined with recent precipitation and/or snow cover will set the stage for fog development, especially where winds remain light. Low temperatures tonight will fall quickly where snow cover exist, with locations along the immediate eastern slopes of the Rocky Mountain Front warming beyond the midnight hour as southwest to westerly surface winds increase. Temperatures look to rebound through the day on Saturday as southwest to west winds across the region; however, a weak cold front dropping southeast and across the plains of North Central and Central Montana late Saturday will help to cool temperatures slightly for the day on Sunday. While a few light rain/snow showers can't be ruled out along and behind this front Saturday night and into the day on Sunday most areas will remain dry through the weekend as upper level ridging amplifies over the Western CONUS/Canada. - Moldan

An upper level system then looks to break down the ridge on Tuesday, initially bringing gusty westerly winds to the plains ahead of a cold front. Upper level troughing hangs around in some capacity from the middle to late portion of next week, which will at the very least cool temperatures across the region. Uncertainty builds with respect to how much precipitation results from this stretch of troughing. -AM

- Forecast Confidence & Scenarios:

Reduced Visibility this evening through Saturday morning :

Hi-Res Ensemble Forecast (HREF) guidance indicates a 30-70% chance for visibilities to fall below 3 miles due to fog within the Milk River Valley of Hill and Blaine Counties, with even a 10-30% chance for visibilities to fall below 0.5 mile. One limiting factor will be mid-level cloud cover, which could hold back visibilities from falling too low. - Moldan

Winds on Tuesday:

The European Extreme Forecast Index continues to highlight Tuesday as a day for gusty winds, mostly across the plains and adjacent areas. Forecast soundings over this timeframe do not show much ridgetop stability, which will make this a pressure gradient and diurnally driven mixing type of event. There is quite a bit of uncertainty associated with it however, as cooler air sinking southward from Canada late Tuesday afternoon or Tuesday evening would shut down the winds rather quickly. Should this front arrive a bit quicker the threat for stronger winds Tuesday would be shorter in duration and more localized.

Unsettled Wednesday through Friday:

Cluster guidance favors troughing across the region over this timeframe, but struggles mightily with respect to timing and strength of the troughing. This results in a lower confidence from a precipitation perspective. Confidence is higher with respect to cooling temperatures however. The main takeaway over this timeframe will be for overall cooler and unsettled conditions at times. -AM

AVIATION

04/00Z TAF Period

Overall, VFR conditions are expected across the CWA through the period. Do expect passing mid/high level clouds, which will be a broken layer at times. Also, some patchy fog is possible, with Bozeman, Lewistown and Havre having the highest probability at this time. Any fog that does develop should burn off by 15z Sat morning. Brusda

PRELIMINARY POINT TEMPS/POPS

GTF 27 57 28 50 / 10 0 0 10 CTB 27 55 26 47 / 0 10 10 10 HLN 24 58 27 58 / 0 0 0 0 BZN 19 58 24 61 / 10 0 0 0 WYS 13 48 17 56 / 0 0 0 0 DLN 21 57 26 63 / 0 0 0 0 HVR 24 57 29 47 / 0 10 10 0 LWT 23 51 28 49 / 10 10 10 10

TFX WATCHES/WARNINGS/ADVISORIES

None.