571
FXUS65 KTFX 040551
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1151 PM MDT Fri Oct 3 2025

Aviation Section Updated.

.KEY MESSAGES...

 - Temperatures continue to cool through Monday morning with the
   coldest temperatures of this fall season so far expected on
   Monday morning.

 - This afternoon and evening there will be isolated showers and
   thunderstorms primarily in Southwestern Montana with widespread
   precipitation expected Saturday night through Sunday morning.

 - Mountain snow is expected Saturday and Sunday with some lower-
   elevation locations seeing a few snowflakes Sunday morning.

&&

.UPDATE...
/Issued 841 PM MDT Fri Oct 3 2025/

Scattered showers and isolated thunderstorms will continue along
and east of the Jackson to Inverness line over the next few hours
before tapering off overnight. Another wave of precipitation will
impact Southwest and Central MT Saturday morning. Light snowfall
will remain at the higher peaks (above 7,500ft-8,000ft) until the
cold front lowers snow levels further Saturday afternoon. The cold
front pushing south from Canada and into Montana early Saturday
morning will bring light precipitation along the Northern Rocky
Mountain Front. About a dusting of light snow is expected in the
mountains above 6,500ft Saturday morning ahead of the "main wave"
of precipitation arriving Saturday afternoon. -Wilson

&&

.DISCUSSION...
/Issued 841 PM MDT Fri Oct 3 2025/

 - Meteorological Overview:

This afternoon the Pacific upper-level trough moves over North-
central, Central, and Southwestern Montana. This will cool down
temperatures and bring another round of showers and thunderstorms to
Central and Southwestern Montana this afternoon through this
evening. This afternoon the greatest potential for any
thunderstorms is in Southwestern Montana. On Saturday the upper-
level trough remains over North-central, Central, and Southwestern
Montana. A surface cold front will move south from Canada during
the day on Saturday. This will lower snow-levels across the
mountains of North-central, Central, and Southwestern Montana and
bring precipitation to the area Saturday afternoon through
Saturday night. On Sunday the upper-level trough will remain over
the area. Precipitation will linger across North-central, Central, and
Southwestern Montana on Sunday. Early Sunday morning snow-levels
across North-central, Central, and Southwestern Montana will
rapidly lower. This will lead to some lower-elevation locations
primarily across North-central Montana seeing light snow between
6 am and noon on Sunday. Sunday morning through Monday morning due
to the cold front it will be the coldest temperatures of the fall
season so far.

On Monday and Tuesday an upper-level ridge builds back in over the
area. This will allow temperatures to slowly warm up with mostly dry
weather across North-central, Central, and Southwestern Montana on
Monday and Tuesday. Wednesday through Thursday there will be an
upper-level ridge over North-central, Central, and Southwestern
Montana with an upper-level shortwave that moves through the
upper-level flow. This will bring about seasonal averages for
temperatures with precipitation chances to the area for Wednesday
and Thursday. -IG

 - Forecast Confidence & Scenarios:

On Saturday there is a 15 - 25% chance for thunder across
Southwestern Montana. On Sunday there is a 15% chance for thunder in
the West Yellowstone area. Saturday through Sunday across North-
central, Central, and Southwestern Montana south of the Hi-Line
there is a 30 - 60% chance for a quarter inch of precipitation or
greater. Saturday through Sunday along the Hi-Line there is a 10
- 40% chance for a quarter inch of precipitation or greater.
Saturday through Sunday in Madison and Gallatin County there is a
40 - 80% chance for a half inch of precipitation or greater.

Saturday morning through Monday morning there is a 50 - 80% chance for
4 inches of snowfall or greater across the mountains of North-
central, Central, and Southwestern Montana. Saturday morning
through Monday morning there is a 50 - 80% chance for 8 inches of
snow or greater across the higher-elevations of the Rocky Mountain
Front and the Madison and Gallatin Mountains. As a result of this
in addition to Logan Pass still being open, a Winter Storm
Warning was issued for the East Glacier Park region from midnight
Saturday through noon on Sunday. Winter Weather Advisories were
issued for the Southern Rocky Mountain Front, Little Belts and
Highwoods, and Snowies and Judiths from midnight Saturday through
noon on Sunday. Also a Winter Weather Advisory was issued for the
Madison and Gallatin Mountains from 6 PM Saturday through 6 PM
Sunday. In the Browning area there is a 40 - 70% chance for an
inch of snow or greater. As a result a Winter Weather Advisory was
issued for the northern high plains from midnight Saturday
through noon on Sunday. Across the lower-elevations of North-
central Montana on Sunday morning there is some uncertainty in
snowfall amounts due this being a northwest flow event. There is a
high chance of most lower-elevations of North-central Montana
seeing at least a few flakes of snow Sunday morning. However, any
snowfall accumulation will be limited to grassy surfaces.

Sunday morning there is greater than a 50% chance for temperatures
of 32 degrees or less across most of the lower-elevations of North-
central, Central, and Southwestern Montana. On Monday morning there
is greater than a 90% chance for temperatures of 32 degrees or
less across most of the lower-elevations of North-central,
Central, and Southwestern Montana. On Monday morning there is
greater than a 70% chance for temperatures of 28 degrees or less
across most of the lower-elevations of North-central, Central, and
Southwestern Montana. -IG

&&

.AVIATION...
04/06Z TAF Period

A dynamic weather system will bring a few rounds of precipitation
throughout the TAF period. Precipitation coverage increases
across Southwest MT as the precipitation shield moves northwards
Saturday morning. A cold front pushing south from Canada
beginning Saturday morning will bring rain and mountain snow. The
front and low pressure system in Southwest MT will bring MVFR cigs
and vis at times throughout the TAF period. There will be
mountain obscuration from lower ceilings throughout the TAF
period. -Wilson

&&

.HYDROLOGY...

There will be increased shower and isolated thunderstorm activity
this afternoon and evening, mostly over central and southwest MT.
While flooding is generally not expected, moisture levels will be
high enough to support rainfall rates up to or greater than a
quarter inch per hour. Flooding and or land slides over burn scars
can`t be ruled out should they undergo heavier downpours. - RCG/AM

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  42  58  34  46 /  40  30  80  60
CTB  39  53  29  45 /  10  40  80  30
HLN  43  58  35  44 /  40  40  80  70
BZN  41  54  34  46 /  60  70  80  70
WYS  35  48  27  44 /  80 100  80  80
DLN  41  52  33  46 /  50  50  40  40
HVR  41  61  34  50 /  60  10  40  20
LWT  42  55  32  44 /  50  50  80  70

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning from midnight Saturday night to noon MDT
Sunday for East Glacier Park Region.

Winter Weather Advisory from midnight Saturday night to noon MDT
Sunday for Little Belt and Highwood Mountains-Northern High
Plains-Snowy and Judith Mountains-Southern Rocky Mountain Front.

Winter Weather Advisory from 6 PM Saturday to 6 PM MDT Sunday
for Gallatin and Madison County Mountains and Centennial
Mountains.

&&

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