textproduct: Great Falls

KEY MESSAGES

- Cool and breezy today with highs in the 60s for most lower elevation locales. - Drier Monday, but showers and thunderstorms return by Tuesday. - Breezy conditions return across Southwestern Montana Wednesday and Thursday.

DISCUSSION

/Issued 231 PM MDT Sun Aug 30 2026/

- Meteorological Overview:

Behind a cold front that pushed through the area overnight, it has been notably cooler across North Central and Southwestern Montana today with most areas on the plains and in the valleys struggling to get out of the 50s and 60s as of early afternoon. While an isolated shower (or even a rumble of thunder) cannot be entirely ruled out across the plains this afternoon, most of us should remain a bit dry, albeit breezy through the remainder of the day thanks to dry air moving into the area.

Weak upper level ridging will begin to transverse the Northern Rockies on Monday, bringing a day of seasonable temperatures and dry weather to the area as it moves overhead. However, the ridge shifts further east on Tuesday, which will allow some moisture to sneak into Southwestern Montana as early as Tuesday afternoon resulting in some showers and thunderstorms. Further north, Tuesday will still be seasonably warm with hiss in the low/mid 80s and generally sunny skies.

Showers and thunderstorms become a bit more widespread Wednesday and Thursday as our next upper level trough moves in from the west coast, which will also bring some increased wind gusts to Southwestern Montana as it does so. While these winds wont be particularly noteworthy on their own, combined with some drier air will result in some elevated fire danger across portions of Gallatin and Madison Counties.

Next weekend will be dictated by how exactly an upper level low off the west coast/Pacific Northwest behaves, and there seems to be some uncertainty as to how exactly it will behave. See the Confidence and Scenarios section below for more details.

- Forecast Confidence & Scenarios:

Winds Wednesday and Thursday: as a series of upper level troughs embedded in persistent upper level southwesterly flow moves overhead, winds will increase, primarily across Southwestern Montana Wednesday and Thursday. While the wind increase looks likely, the magnitude, extent, and duration of the winds are likely to be quite sensitive to the exact track of these disturbances. As of Sunday, the NBM probabilities seem to indicate that there are roughly similar probabilities for wind gusts over 45 mph, with chances around 50% generally confined to some of the North/South oriented valleys of Southwestern Montana near and south of Interstate 15.

Next Weekend: There are a few ways next weekend could pan out, largely driven by how strong an upper level trough gets over the west coast and whether or not it cuts off from the flow and becomes a closed upper level low. There does seem to be a little more support for the latter scenario (around 75% of the ensemble members), but its strength and location will play a large role in the details of our weather, and models seem to be in quite a bit of disagreement with these particulars. Should the low/trough wind up staying offshore, next weekend is likely to be a bit on the warmer side of the forecast, with upper level ridging building in overhead. However, a more eastward placement of this low/trough, which is around 60% of the ensemble members would result in a cooler, more unsettled result for next weekends weather. Ludwig

AVIATION

31/00Z TAF Period

VFR conditions will prevail throughout this TAF period, with skies clearing by 06Z. Winds will begin to decrease around 03Z, becoming southwesterly and relatively light.

For KGTF: Winds will begin to decrease around 02Z, becoming southwesterly near 08 kts around 06Z. Winds will become light and variable around 13Z, and will remain so throughout the rest of this TAF period. Due to the southwesterly direction of these winds, there is a less than 10% chance of a cross-wind exceeding 15 kts. VFR conditions will prevail throughout this TAF period, and skies will clear to FEW250 by 02Z. -Dzomba

PRELIMINARY POINT TEMPS/POPS

GTF 45 78 48 85 / 0 0 0 0 CTB 43 75 44 84 / 10 0 0 0 HLN 43 79 47 84 / 0 0 0 0 BZN 40 78 45 80 / 0 0 0 10 WYS 30 72 35 71 / 0 0 20 50 DLN 39 80 44 80 / 0 0 0 20 HVR 46 77 47 88 / 10 0 0 0 LWT 42 75 46 82 / 0 0 0 0

TFX WATCHES/WARNINGS/ADVISORIES

None.