362
FXUS65 KTFX 091950
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
150 PM MDT Sun Mar 9 2025

.KEY MESSAGES...

 - Strong winds spread further onto the plains late tonight into
   Monday morning behind a cold front.

 - Increasing risk for gusty winds across Southwest Montana
   Wednesday.

 - Late week system bringing a mix of rain and snow to lower
   elevations, with all snow in the mountains.

&&

.DISCUSSION...

 - Meteorological Overview:

Broad upper level ridging across the western CONUS has resulted in a
largely zonal flow across the Northern Rockies today. Already strong
winds aloft will be enhanced further tonight going into tomorrow by
a shortwave presently over the far eastern Pacific Ocean. The result
is for a period of strong winds, initially along the Rocky Mountain
Front and adjacent plains today, spreading further onto the plains
and adjacent areas tonight along and behind a cold front. There are
a few exceptions though, as gusty winds do look to develop in the
more wind prone areas of Central Montana ahead of the front thanks
to increasing flow near the surface being translated to the surface
by mountain wave activity. Regardless, surface winds begin to
diminish late Monday morning across western areas, with eastern
areas seeing winds fall off later in the afternoon.

Meanwhile, Pacific moisture associated with the aforementioned wave
will result in a period of mainly above pass level snow along the
Rocky Mountain Front late tonight into Monday. Although a few inches
of snow will be possible at Marias Pass, surface temperatures
through the day today and tonight will help result in at least some
melting of snow that does fall there. Hence, given the lack of
significant impact at pass level, a WInter Weather Advisory is not
being considered at this time.

After a cooler day Monday, temperatures trend warmer again Tuesday
and especially Wednesday across the region ahead of the next system
set to arrive Wednesday night. Southwest flow increases aloft during
the day Wednesday, with forecast soundings in Dillon and vicinity
showing relatively deep mixing into these stronger winds aloft.
Hence, a breezy day in Southwest Montana is increasing in likelihood
for Wednesday, with a non-zero chance for a rain, graupel, or snow
shower, depending on temperature and elevation.

A potent trough will spread across the western CONUS late this week,
although the most impressive embedded wave does look to track well
south of the Northern Rockies. None-the-less, at least some moisture
from this system does look to make inroads across Montana, with a
mix of rain and snow at lower elevations and mountain snow late
Wednesday night through Friday. -AM

 - Forecast Confidence & Scenarios:

Winds through Monday afternoon:

Forecast soundings are quite impressive in and around the Cut Bank
area tonight around and after midnight, showing 70+kts near the
surface. It would not surprise me if higher end gusts were realized
in this area tonight with the front helping mix things better. For
the time being, 75 mph is the highest gust mentioned in the High
Wind Warning for this area.

SW MT winds Wednesday:

Probabilistic guidance gives around a  30% chance for a 58 mph gust
in the Dillon and Twin Bridges area for Wednesday. Along the I-90
corridor between Three Forks and Homestake Pass the chance for a 58
mph gusts drops a bit, down to 20%.


Precipitation Wednesday night into Friday:

Deterministic guidance has trended precipitation amounts down over
the plains for this system, though ensembles haven`t trended down
quite yet. Trends will need to be monitored with ensembles if
deterministic guidance continues to trend down. Mountain areas in
Southwest Montana are still favored for accumulating snow. -AM

&&

.AVIATION...
09/18Z TAF Period

The primary concern this TAF period is for strong surface winds
along the Rocky Mountain front today and spreading onto the plains
tonight, low-level wind shear mostly in wind protected valleys, and
mountain wave turbulence, most notably along the Rocky Mountain
Front. Additionally, a cold front will bring about a shift in wind
direction from west-southwest to west-northwest late tonight into
tomorrow across the plains and adjacent areas. Mountain obscuring
precipitation is forecast along the Northern Rocky Mountain Front
late tonight into tomorrow morning. -AM

Refer to weather.gov/zlc for more detailed regional aviation
weather and hazard information.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  41  48  35  55 /   0  20   0   0
CTB  32  44  29  48 /  20  20   0   0
HLN  35  46  30  51 /   0  20  10  10
BZN  28  45  25  49 /   0  30  20   0
WYS  18  40  20  42 /  10  20  20   0
DLN  30  50  28  52 /   0  10   0   0
HVR  32  46  25  53 /   0  20   0   0
LWT  35  43  26  49 /   0  30   0  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
High Wind Warning from 6 AM to 6 PM MDT Monday for Bears Paw
Mountains and Southern Blaine-Cascade County below 5000ft-Fergus
County below 4500ft-Hill County-Judith Basin County and Judith
Gap-Little Belt and Highwood Mountains-Northern Blaine County-
Snowy and Judith Mountains.

High Wind Warning until 1 PM MDT Monday for East Glacier Park
Region-Eastern Glacier, Western Toole, and Central Pondera-
Northern High Plains-Southern High Plains-Southern Rocky
Mountain Front.

High Wind Warning from midnight tonight to 6 PM MDT Monday for
Eastern Pondera and Eastern Teton-Eastern Toole and Liberty.

&&

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