Lewistown, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

392
FXUS65 KTFX 251059
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
359 AM MST Thu Dec 25 2025

.KEY MESSAGES...

- Wintry mixed precipitation and freezing rain ends in a southwest
  to northeast fashion this morning.

- Temperatures will be mild for most for the next couple of
  days, although colder air will linger along the Hi-Line.

- Another weather system and attendant cold front will bring a period
  of areawide light snow and and much colder temperatures late
  Friday into Saturday.

- Temperature will trend near to above average for most locations
  heading into early next week, but the colder air will linger
  along the Hi-Line and over the southwest valleys.

&&

.DISCUSSION...

 - Meteorological Overview:

An additional round of mixed precipitation and freezing rain will
continue to move east and northeast over the plains for next few
hours with the Arctic air retreating north as the precipitation
ends later this morning. Mild and breezy to windy conditions
generally prevail for the next day or so with a weak shortwave
bringing more mountain snow tonight into Friday.

The next system arrives late Friday into Saturday and will be
stronger and colder than previous ones with H700/H500 temperatures
falling to -15C/-30C near its axis. This will result in more
substantial mountain snow and even lower elevation light snow
during the frontal passage. This upper level support will send the
Arctic boundary all the way into southwest MT, at least briefly.

A Northwesterly flow aloft will set up heading into early next
week while high pressure builds to our west. Milder and breezy
conditions look to return for most locations, but the colder air
may be reluctant to leave the normally colder river/wind protected
valleys of north-central and southwest MT. - RCG

 - Forecast Confidence & Scenarios:

Freezing rain, drizzle, and patchy fog diminishes and improves
from southwest to northeast this morning...

The main area of freezing rain has crossed the Canadian border
leaving a widespread coating of ice generally ranging from trace
amounts to around 0.05 inches. Despite the low precipitation
amounts, the impacts to roads have been rather significant with
severe driving conditions and scattered road incidences being
reported between Dearborn and Havre and then in the Choteau area.
Another wave of freezing rain will move through between now and
mid-morning and bring an additional few hundredths of an inch of
incing. The latest hires guidance shows the last of the freezing
rain exiting the Hi-Line around 9 to 10 AM. The winter weather
advisory was extended for this area while the remainder advisory
area to the south and west tentatively looks ok to expire at 5 am
with lighter precipitation and warmer air poised to move in from
the southwest.

Mostly mountain snow and winds tonight through Saturday...

A weak shortwave will bring a round of mountain snow tonight into
Friday, mostly impacting the Northern Rocky Mountain Front and
the southern portion of the Madison and Gallatin mountain ranges.
The latter will have the best chance (50 to 80%) for 3 inches of
snow or more.

The stronger and colder trough will arrive late Friday into
Saturday and will deliver a more widespread snowfall. Snow will
again be heaviest in the mountains, especially along the Rocky
Mountain Front where Marias Pass stands around a 50% chance for 6
inches of snow or more. With an Arctic airmass finally being able
to clear the entire forecast area on Saturday, most lower
elevation look to see amounts ranging from a trace up to a couple
of inches. Winds don`t look overly impressive with either of the
aforementioned systems, but locations along the Rocky Mountain
Front look to see wind gusts over 60 mph at times on Friday. - RCG

&&

.AVIATION...
25/06Z TAF Period

Freezing rain has started across central Montana and will continue
to push to the northeast over the next few hours, generally
diminishing by 25/12Z.

Across North-Central Montana, visibility temporarily improves
when the precipitation first arrives but so far it has not been
strong enough to full mix out the dense freezing fog so, for now,
LIFR/VLIFR conditions will be prevailed at KGTF, KHVR, and KCTB.
Fog tried to develop around KLWT earlier but has since lifted and
it is unlikely it will redevelop as mid level clouds are in place
directly over the Lewistown area. The rest of North-Central
Montana remains covered in dense fog with visibilities ranging
from 2SM to 1/4SM or less. Visibilities are expected to improve
after 25/10Z with some lingering IFR/MVFR ceilings until around
25/18Z at which point VFR conditions will return to the region.

Across southwest Montana, precipitation will linger through at
least 25/16Z with snow expected in the mountains and rain at lower
elevations including KBZN and KEKS.

Mountain obscuration will be common this TAF period, especially
around areas of precipitation.  -thor

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  50  34  50   9 /  10  10  10  20
CTB  42  24  38  -2 /  10   0  10  30
HLN  48  31  46  22 /  30  30  30  50
BZN  50  32  49  23 /  40  30  40  30
WYS  40  28  36  18 /  90  90 100  70
DLN  49  31  44  24 /  30  30  30  20
HVR  30  23  38   3 /  70  10  20  20
LWT  52  35  50  13 /  20  10  10  20

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 9 AM MST this morning for Bears
Paw Mountains and Southern Blaine-Eastern Toole and Liberty-Hill
County-Northern Blaine County.

Dense Fog Advisory until 9 AM MST this morning for Fergus County
below 4500ft-Western and Central Chouteau County.

Winter Weather Advisory until 5 AM MST early this morning for
Cascade County below 5000ft-Eastern Glacier, Western Toole, and
Central Pondera-Eastern Pondera and Eastern Teton-Gates of the
Mountains-Northern High Plains-Southern High Plains-Western and
Central Chouteau County.

&&

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