418
FXUS65 KTFX 112331
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
531 PM MDT Sat Oct 11 2025

Aviation Section Updated.

.KEY MESSAGES...

 - It will be windy this afternoon and Sunday with showers and
   thunderstorms primarily in Southwestern and Central Montana.

 - Tonight through Monday it will be significantly colder with
   mountain snow and lower elevation snow/rain with most of the
   lower elevation snow expected Sunday night into Monday
   morning.

 - Tuesday through Friday it will warm up with daily precipitation
   chances.

&&

.DISCUSSION...
/Issued 247 PM MDT Sat Oct 11 2025/

 - Meteorological Overview:

This afternoon there is an upper level trough and an associated
cold front that have moved across most of North Central, Central
and Southwestern Montana. Ahead of and along the front there is
the risk for isolated thunderstorms with the greatest risk in
Southwestern Montana. Ahead of and along the front there will be
showers. Tonight cold air from Canada will move into North
Central, Central, and Southwestern Montana behind the front this
will lower-snow levels across the area and bring a rain/snow mix
to most lower elevations of North Central Montana and rain to the
valleys of Central and Southwestern Montana and heavy mountain
snow. On Sunday the upper level trough remains over the area in
the morning before an upper level ridge moves over the area. Due
to the cold front on Sunday temperatures across North Central
Montana will be well below seasonal averages and below seasonal
averages across Central and Southwestern Montana. Across most
locations there will be a precipitation lull between noon Sunday
and Sunday evening. Sunday evening there will be a warm front
situated across Central Montana. This combined with low level
easterly flow will allow for another round of snowfall due to
isentropic lift. This round of snowfall will primarily effect
North Central and Central Montana Sunday evening through noon on
Monday.

On Monday the upper level ridge remains over North Central, Central,
and Southwestern Montana. This will allow the area to dry out for
the most part on Monday. On Tuesday the upper level ridge remains
over North Central, Central, and Southwestern Montana. This will
allow temperatures to begin to warm up across the area with mostly
dry weather. Wednesday through Friday an upper-level trough moves
over North Central, Central, and Southwestern Montana. This will
allow temperatures to warm up some with daily precipitation chances.
IG

 - Forecast Confidence & Scenarios:

There is greater than a 60% chance for 8 inches or more snowfall
across most of the mountains of North Central, Central, and
Southwestern Montana through noon on Monday. Along the Rocky
Mountain Front there is a greater than a 80% chance for 12 inches
of snow or greater through noon on Monday. As a result Winter
Storm Warnings are in effect for the Rocky Mountain Front from
this evening through noon on Monday and Winter Weather Advisories
are in effect for MacDonald Pass/Lincoln and the Little
Belts/Highwoods from this evening through noon on Monday and for
the Madison and Gallatin Mountains through noon on Sunday. There
is greater than a 60% chance for 4 inches of snow or greater along
the northern and southern high plains adjacent to the Rocky
Mountain Front from this evening through noon on Monday. As a
result Winter Weather Advisories were issued for those areas from
this evening through noon on Monday. Along I-15 from Cut Bank to
Helena and along the US Highway 87/Montana Highway 200 Corridor
between Great Falls and Lewistown there is greater than a 50%
chance for 2 inches of snowfall or greater from Sunday evening
through noon on Monday. For the lower elevations between Great
Falls and Geyser south to the Helena Valley there is a 30 to 50%
chance for 4 inches of snow or greater from Sunday evening through
noon on Monday.

Across the lower elevations of North Central Montana it is expected
that at least some of the snow that falls tonight into Sunday
morning will melt. There remains uncertainty in how much snow across
North Central and Central Montana will melt initially Sunday
night into Monday morning. Due to the expected impacts from the
snow at most lower elevation locations being more than 24 hours
out, at this time no additional Winter Weather Advisories are
being issued. Future shifts will continue to evaluate the need for
Winter Weather Advisories for lower elevation locations. IG

&&

.AVIATION...
12/00Z TAF Period

Initial concerns this TAF period will be for lower elevation rain
and mountain snow across eastern portions of the region early
overnight. Attention then turns to a cold front moving south from
Canada late this evening into Sunday morning, which will shift
winds to a more north to northwesterly direction.

Much cooler air works in behind this front, which will result in
brief periods of snow at many lower elevation locations into Sunday
morning. Low clouds and mountain obscuration will become
increasingly widespread through the evening and overnight,
especially over North-central MT. -AM

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  32  39  26  35 /  70  80  90  70
CTB  24  34  21  32 /  70  70  80  70
HLN  36  42  26  38 /  80  80 100  50
BZN  34  47  27  43 / 100  60  60  20
WYS  23  37  17  51 / 100  60  20  10
DLN  32  49  29  47 /  80  30  40  10
HVR  26  42  23  41 /  60  50  40  30
LWT  29  39  23  37 /  90  50  70  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until noon MDT Monday for East Glacier Park
Region-Southern Rocky Mountain Front.

Winter Weather Advisory from midnight tonight to noon MDT Monday
for Little Belt and Highwood Mountains-Northern High Plains-
Southern High Plains-Upper Blackfoot and MacDonald Pass.

Winter Weather Advisory from 9 PM this evening to noon MDT
Sunday for Gallatin and Madison County Mountains and Centennial
Mountains.

&&

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