063 FXUS65 KTFX 112041 AFDTFXArea Forecast Discussion National Weather Service Great Falls MT 241 PM MDT Thu Sep 11 2025
.KEY MESSAGES...
- Isolated to scattered showers and thunderstorms this afternoon, some of which could produce some gusty winds or localized heavy rain. - Briefly warmer Sunday. - Cool and unsettled weather returns on Monday.
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.DISCUSSION...
- Meteorological Overview:
A broad, slow moving, and gradually weakening upper level trough currently over the Western US will keep us cool and unsettled the next few days before another trough approaches from the west and forces it to move northward on Sunday. With this trough to the west, expect Sunday to be slightly warmer highs generally 3-5 degrees warmer than the previous few days. Showers and thunderstorms will continue to be around, however, especially later in the day as afternoon heating combines with the approaching upper level trough. This trough will settle overhead for the first half of the week, bringing cool and unsettled to the area for the first half of next week.
- Forecast Confidence & Scenarios:
The main impacts over the next few days will be the low end risk for an isolated strong and/or heavy thunderstorm, particularly this afternoon and Friday afternoon. Forecast soundings the next two days tend to show a tall, skinny CAPE profile (CAPE being a measure of instability), which indicates an elevated chance for some heavy rain out of any shower or thunderstorm. WPC does align with this expectation, as we are under a Marginal () risk for excessive rainfall. For the most part, the main concern will be any recent burn scars (such as the Horse Gulch or any active fires). In addition to the rain, a few stronger wind gusts will be possible from some of the storms as well, particularly further east across the plains (generally east of a Great Falls to Havre line).
Looking into next week, there isnt much impactful weather expected at this time, though showers and thunderstorms are expected most days. Also of note, with the upper level low across the area in the first part of next week, I cant really rule out some snow falling at the higher elevations of Beaverhead, Madison, and Gallatin Counties. While any snow accumulations will be light and isolated to the highest terrain, it is still noteworthy as some of the first snow of the season. Ludwig&&
.AVIATION... 11/18Z TAF Period
VFR conditions will prevail across all terminals through the TAF period outside of shower/thunderstorm activity. The main threats with any thunderstorm that develops will be frequent lightning, locally heavy downpours, and gusty/erratic winds. Mountain obscuration will be a concern through much of the period, especially between now and 12/06Z.
North-Central/Central Montana (KCTB, KHVR, KGTF, KLWT, KHLN): There will be a 20-50% chance for showers and thunderstorms across the region throughout much of the TAF period. Thunderstorms today have the potential to be stronger, particularly towards the east affecting KHVR and KLWT which may include small hail in addition to the previously mentioned threats.
Southwest Montana (KBZN, KEKS, KWYS): The main threat for showers and thunderstorms will be from now through 12/00Z. Overnight, clouds will start to clear out with a slight chance for fog through the morning hours, particularly at KWYS. There will be another 20-40% chance for scattered showers across the region tomorrow after 12/18Z.
-thor
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.HYDROLOGY...
A few heavy showers and thunderstorms are possible today. While unlikely, should one of the heaviest rain showers hit a burn scar some flash flooding may be possible. Ludwig
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.PRELIMINARY POINT TEMPS/POPS... GTF 50 77 49 78 / 40 30 20 20 CTB 48 76 46 77 / 20 30 20 10 HLN 49 77 49 76 / 40 40 20 30 BZN 43 76 44 71 / 20 30 10 30 WYS 33 70 34 63 / 10 30 20 50 DLN 41 72 41 70 / 20 30 10 20 HVR 54 78 51 78 / 40 40 30 20 LWT 48 75 47 71 / 30 40 40 50
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.TFX WATCHES/WARNINGS/ADVISORIES... None. &&
$$ http://www.weather.gov/greatfalls
NWS TFX Office Area Forecast Discussion