109
FXUS65 KTFX 291726
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1026 AM MST Sat Nov 29 2025

Aviation Section Updated.

.KEY MESSAGES...

 - Coldest air of the season thus far settled into the area
   overnight and will linger into Monday morning.
 - Next round of widespread snowfall arrives Tuesday.
 - Unsettled pattern looks likely late next week and beyond.

&&

.UPDATE...
/Issued 814 AM MST Sat Nov 29 2025/

Today it will be cold across North-central, Central, and
Southwestern Montana with the coldest temperatures of the winter
so far across North-central and Central Montana. Wind chills along
the Hi-Line this morning will approach 25 below zero. Given that
those cold wind chills aren`t widespread and it will only last for
a couple hours this morning a Cold Weather Advisory was not
issued at this time. Late this afternoon through tonight there
will be light snow across portions of Southwestern Montana. For
the update, temperatures across the Hi-Line were decreased to
reflect current observations and trends. For late this afternoon,
through tonight PoPs were increased across Southwestern Montana to
reflect the latest hi-res model guidance. The rest of the
forecast is on track. -IG


&&

.DISCUSSION...
/Issued 814 AM MST Sat Nov 29 2025/

Thanks to high pressure building at the surface and strong
northerly flow aloft, the coldest air of the season so far has
made its way into North Central and Southwestern Montana
overnight, resulting in most locations seeing low temperatures dip
into the single digits to below 0 overnight. This cold air will
moderate during the day, but will remain well below freezing,
which will make any icy roads slow to improve. Temperatures will
moderate a bit on Sunday as the surface high pressure system
slides to the east, allowing southerly surface flow to slowly
erode the cold air out of the area.

Temperatures will further moderate through the first half of the
new week as upper level flow becomes a bit more zonal/westerly,
allowing warmer air to spill over the Continental Divide, though
this will also result in winds picking up and possibly resulting
in some mild blowing/drifting of the recent snowpack.

Upper level troughing will be quick to return to the area on
Tuesday, however, bringing our next round of snowfall to the area
as it does. While this system does not appear to have as much
moisture to work with as our departing system did, there will
still be enough snow to cause some minor travel impacts,
particularly on the North Slopes of the Little Belt and Snowy
Mountains (along and south of a Great Falls to Lewistown line).

Behind this system, uncertainty increases on details, but overall
models seem to suggest a generally active and unsettled weather
pattern, with multiple chances for at least some mountain snowfall
for the second half of the week. Ludwig

&&

.AVIATION...
29/18Z TAF Period

VFR conditions with mainly clear skies and light surface winds
prevail through this afternoon. A weather disturbance moving
across Idaho will spread mid-high clouds across SW MT this evening
with some mountain obscuration light snow showers possible as far
north as KDLN to KEKS. Fog development is a concern on the plains
tonight with most model guidance suggesting its development from
KHVR west to KCTB and KGTF. Hoenisch

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  17  -4  20   8 /   0   0   0   0
CTB   6  -8  18   7 /   0   0   0   0
HLN  19   6  25  11 /   0   0   0   0
BZN  19   5  24   5 /   0  10   0   0
WYS  21   7  29   2 /   0  20  10   0
DLN  23  15  28  10 /   0  30   0   0
HVR   0 -15   5  -8 /   0   0   0   0
LWT  16  -1  23   7 /   0   0   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&

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