410
FXUS65 KTFX 310520
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1120 PM MDT Sun Aug 30 2026

Aviation Section Updated.

.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...
31/06Z TAF Period

Scattered mid-level cloud cover along and north of the US Hwy 2
corridor will gradually dissipate through 09-12z Monday, with
otherwise VFR conditions expected through the 2106/0106 TAF period.

For KGTF: Winds will remain predominately out of the southwest
through 21z Monday, with the probability for crosswinds being
exceeded below a 5% chance. Beyond 21z Monday winds will become
light and variable. - Moldan


&&

.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.
&&

$$
http://www.weather.gov/greatfalls