610
FXUS65 KTFX 092333
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
433 PM MST Sun Nov 9 2025

Aviation Section Updated.

.KEY MESSAGES...

- Mild and breezy to windy conditions are expected for much of
  the workweek with the warmest temperatures on Monday and
  Thursday.

- Monday`s winds will become strong at times along the
  Rocky Mountain Front and over the plains west of I15.

- A broad Pacific trough moves into the Northern Rockies heading
  into the weekend, bringing a slight cooldown and a return of
  mountain snow.

&&

.DISCUSSION...
/Issued 302 PM MST Sun Nov 9 2025/

 - Meteorological Overview:

Stubborn low clouds and patchy fog along the Milk River Valley
has been the primary concern for much of today. The fog has since
dissipated and any redevelopment tonight will be temporary with
increasing high level cloudiness and southwesterly breezes moving
into most of this area around or shortly after midnight.

Ridging aloft will flatten with strong westerly flow developing
late tonight into Monday on the order of 50 to 80 kts between 500
and 700 mb. Mountain wave activity and a tightening surface
pressure gradient will compliment the increased westerly flow
aloft and bring periods with winds gusting in the 60 to 75 mph
range along the Rocky Mountain Front and the plains west of I15.
Winds will be gusty east of I15 as well, but warm air advection
and extensive high clouds should preclude widespread instances of
55 mph + surface wind gusts. If any gusts do occur in these areas
it will be in the evening hours when a shortwave with weak
northwest to southeast oriented cold air advection passes though
the region.

Breezy and mild conditions are expected for much of the remaining
workweek with afternoon temperatures running as high as 15 to 20
degrees above average, warmest on Thursday. A broad split trough
then approaches the Northern Rockies late Thursday through
Saturday. Winds shouldn`t be as strong with this trough being more
meridional oriented, but southerly flow aloft may bring windy
conditions to the southwest late Thursday into Friday. There`s an
expectation for increased precipitation and mountain snow Friday
and Saturday despite at least a portion of this system`s energy
looking to dive southward into the Great Basin. Ensemble members
diverge for the second half of the weekend into early next week,
with timing discrepancies between troughs and ridges. - RCG

 - Forecast Confidence & Scenarios:

Periods of strong winds along the Rocky Mountain Front and plains
west of I15 on Monday...

There`s a general expectation for windy conditions over much of
North-central Montana on Monday given the elevated westerly flow
aloft mentioned above. With warm air advection and cloud cover
inhibiting widespread surface transfer of the stronger upper level
flow, there will be a higher dependence on mountain wave activity
to bring stronger winds to the surface. This will confine the
strongest winds to areas along the Rocky Mountain Front and the
plains along and west of I15, with that boundary even shifting
farther west to highway 89 for plains locations south of Pendroy.
There looks to be a period of strong winds late tonight into
Monday morning and then again in the afternoon. Most of these
areas have a 60 to 90% chance for gusts exceeding 55 mph with a 50
to 80% chance for gusts exceeding 75 mph over the immediate
eastern slopes of the Rocky Mountain Front. Winds will mostly stay
in the 30 to 50 mph range for other locations, but a few isolated
gusts over 55 mph may occur during the passage of a weak cold
front late Monday afternoon and evening. All the high wind watches
were upgraded to warnings which now run from 2 am to 9 pm. I also
considered adding the Sweetgrass hills as well with the stripe of
H850 winds moving though on Monday , but held off for now because
if the aforementioned confounding factors. This situation will be
monitored by incoming shifts. - RCG

&&

.AVIATION...
10/00Z TAF Period

The main concern this TAF period will be for increasing surface
winds, primarily over the plains. A few instances of low-level wind
shear will be around through the early overnight on the plains as
surface winds remain weaker for a few hours while winds aloft
increase. Confidence was highest in this occurring at KCTB over
an extended period, with confidence too low in an extended
duration of LLWS elsewhere to include in TAFs at this time. Gusty
surface winds become more common through the morning and early
afternoon Monday, mostly over the plains. -AM

The KWYS TAF will not be issued until airport operations resume
next spring.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  44  65  44  58 /   0  10   0   0
CTB  40  62  37  52 /   0  10   0   0
HLN  34  61  41  57 /   0   0   0   0
BZN  30  62  34  59 /   0   0   0   0
WYS  18  48  24  47 /   0   0   0   0
DLN  32  60  33  56 /   0   0   0   0
HVR  28  62  35  57 /   0  10   0   0
LWT  35  64  39  56 /   0   0   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
High Wind Warning from 2 AM to 9 PM MST Monday for East Glacier
Park Region-Eastern Glacier, Western Toole, and Central Pondera-
Northern High Plains-Southern High Plains-Southern Rocky
Mountain Front.

&&

$$
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