textproduct: Great Falls

KEY MESSAGES

- Unseasonably warm and dry weather persists through Friday.

- Windy conditions Friday lead to elevated fire weather concerns.

- Change to much cooler and wetter weather this weekend with potential for impactful mountain snow.

DISCUSSION

/Issued 253 AM MDT Tue Oct 6 2026/

- Meteorological Overview:

Low amplitude upper level ridging across the western US will maintain unseasonably warm and dry conditions across the area through Friday beneath a west-northwest flow aloft. Afternoon temperatures will run slightly lower than those of Monday but still around 15 degrees above early October climatological averages. Afternoon mixing and a moderate surface pressure gradient across the Rockies will support some breeziness this afternoon, mainly across the plains, with overall lighter winds Wed and Thu as surface high pressure slides east across the Canadian Prairies.

An upper level trough digging southeast through BC Friday will bring a significant weather pattern change for the weekend with windy conditions developing Friday as southwesterly mid-level flow increases ahead of the approaching trough. Warm, windy and dry conditions Friday will bring elevated fire weather concerns ahead of a cold front Friday night that brings in much cooler and wetter conditions for the weekend. Model guidance is in reasonable agreement to dig the trough southward into the NW US Saturday with typical differences and spread still at this time range among models/ensemble members in the eventual evolution of the trough through the rest of the weekend into early next week.

- Forecast Confidence & Scenarios:

Fire Weather: While wind speeds through Thursday will not be significant, warm afternoon temperatures and low afternoon humidity will persist with only moderate to locally poor overnight humidly recovery, especially over the central MT mountains and adjacent slopes. These condtions may advance the curing and drying of lighter (grass/shrub) fuels that are already headed into seasonal dormancy. Increased winds with potential for gusts in excess of 40 mph Friday, alongside the continued warmth/dryness will bring an elevated fire weather risk.

Weekend Pattern Change/Impacts: Confidence continues to increase in the overall influx of much cooler temperatures this weekend, along with widespread precipitation and at least some impactful mountian snowfall. Temperatures on Saturday are likely to be 25-30 degrees colder than Friday with additional cooling arriving Saturday night into Sunday. While not unusual for early October, this will be the first of such drastic seasonal swings and will follow an extended period of mild weather. A majority of model ensemble members support snow levels falling to below 4000 ft by Sunday, which brings the risk for wet snowfall down to lower elevations. However, there is still a very large spread in precipitation amounts/scenarios and timing due to key details that will continue to be resolved over the coming days. Hoenisch

AVIATION

06/12Z TAF Period.

VFR conditions prevail through the TAF period with just some passing high clouds. Westerly surface winds increase some across the plains and central MT terminals this afternoon before diminishing again this evening. Hoenisch

PRELIMINARY POINT TEMPS/POPS

GTF 80 45 72 42 / 0 0 0 0 CTB 75 41 67 39 / 0 0 0 0 HLN 80 43 77 43 / 0 0 0 0 BZN 78 42 75 40 / 0 0 0 0 WYS 74 34 73 31 / 0 0 0 0 DLN 79 42 77 40 / 0 0 0 0 HVR 77 42 71 37 / 0 0 0 0 LWT 77 46 73 42 / 0 0 0 0

TFX WATCHES/WARNINGS/ADVISORIES

None.