mt discuss
Office: TFX
FXUS65 KTFX 171952
AFDTFX
Area Forecast Discussion
National Weather Service Great Falls MT
1252 PM MST Mon Nov 17 2025
.KEY MESSAGES...
- Patchy fog development is once again possible tonight through
Tuesday morning across the Hi-Line in North Central Montana and
in prone valleys of Southwest Montana.
- Passing weather systems will bring spotty areas of light rain
and mostly mountain snow through Wednesday.
- A more progressive weather pattern brings a return of breezy to
windy conditions and mountain snow this weekend, followed by a
shift to more wintry conditions heading into the Thanksgiving
holiday.
&&
.DISCUSSION...
- Meteorological Overview:
A moist, but weak, southwesterly flow aloft will persist until
Wednesday when a Pacific trough passes through the Northern
Rockies. This will maintain variably cloudy skies and periods of
lighter end rain and snow. Snow levels will be lowest on Wednesday
while the trough axis moves overhead; however, negligible
precipitation amounts and the lack of colder air aloft will offer
little support for accumulating snow. Lingering moisture and light
winds throughout the atmospheric profile will also encourage
areas low stratus and patchy fog to develop over the next couple
of days. This looks to be most prevalent during the overnight and
morning hours near river valleys.
Drier conditions move in for the second half of the workweek with
another Pacific trough diving southeastward into Great Basin and
southwest US. Then the upper level jet moves into the Northern
Rockies this weekend and brings periods mostly mountain snow,
breezy to windy conditions, and cooler temperatures. A series of
troughs may then bring colder temperatures and even periods of
snow for the week of Thanksgiving, though model guidance has been
divergent, especially in terms of trough amplitude and timing.
- RCG
- Forecast Confidence & Scenarios:
Patchy Dense Fog tonight through Tuesday morning...
Hi-Res Ensemble Forecast (HREF) guidance generally supports
between a 10-30% chance for visibilities to fall below 1/4 mile
along the Hi-Line in North Central Montana, most notably across
Hill and Blaine Counties, and in the West Yellowstone Area. BUFKIT
analysis for these same areas casts some doubt as to whether any
fog will materialize given the presence of low cloud cover, with
the current thinking being that a low stratus deck is more likely
to prevail; however, patchy dense fog is possible in prone areas
if enough clearing can occur during the period. - Moldan
Scattered areas of light rain and snow through Wednesday...
Rain and snow associated with an approaching Pacific weather
system looks to be light and scattered in nature. Temperatures
aloft will not be favorable for accumulating snow until the trough
axis moves overhead on Wednesday. Even then, probabilities for
one inch of snow or more will be around 20% in the mountains and
near zero for lower elevations.
Increasing winds and mountain snow this weekend...
Winds increase heading into the weekend while mountain snow
returns, mostly along the Continental Divide. Recent ensemble runs
have begun to favor the jet stream setting up a little farther
north with shallower troughing. If this trend continues, it would
shift the mountain snow farther north, just clipping the Rocky
Mountain Front. Areas of higher terrain to the south and the
plains/valleys would see little to no precipitation. A more
southerly trajectory would bring more mountain snow, especially
the northwesterly upslope areas, including the central island
ranges and the Madison and Gallatin ranges. The strongest
shortwave and best chance for precipitation looks arrive Saturday
night into Sunday. Westerly surface winds will also be on the
increase with many central and north-central locations seeing
winds in the 30 to 50 mph range.
More wintry pattern shift for the week of Thanksgiving...
Nearly all ensemble members usher in below average temperatures
for the days leading up to Thanksgiving, but only around a third
of them highlight impactful accumulating snow. There are still
significant differences with trough amplitude and timing and there
also has been poor model run to run consistency. Overall,
preparations should be made for the arrival of the coldest
temperatures of the season so far with probabilities for below
freezing highs climbing above 70% for most areas next Tuesday
through Thursday. - RCG
&&
.AVIATION...
17/18Z TAF Period
Weak southwesterly flow aloft will maintain variable cloudiness and
spotty areas of light rain for much of the TAF period. In general,
VFR conditions will prevail but there will be some mountain
obscuration, mostly along the Continental Divide and over
southwest MT. Fog may develop overnight along the Milk River
Valley impacting KHVR but the more likely scenario right now is a
low stratus deck with no significant reductions in visibility
expected. -RCG/thor
The KWYS TAF will not be issued until airport operations resume
next spring.
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 39 56 31 45 / 10 10 10 20
CTB 34 51 31 43 / 20 20 10 10
HLN 36 53 31 45 / 10 10 10 30
BZN 36 54 33 44 / 10 10 10 30
WYS 31 41 28 40 / 40 20 10 40
DLN 34 51 29 47 / 10 10 0 10
HVR 32 48 29 43 / 10 10 20 10
LWT 36 55 28 43 / 10 10 10 20
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
http://www.weather.gov/greatfalls
Office: MSO
FXUS65 KMSO 171923
AFDMSO
Area Forecast Discussion
National Weather Service Missoula MT
1223 PM MST Mon Nov 17 2025
.DISCUSSION...
KEY MESSAGES:
- Through Friday: Mild temperatures with light periodic showers.
Patchy, locally dense fog likely during overnight and morning
hours
- This Weekend (Nov 22-23): Minor atmospheric river event. Snow
levels of 4500-5500 feet, limiting winter impacts to pass
levels
- Thanksgiving Week: Pattern shift to colder, wintry weather.
Increasing potential for valley snow and slick travel
Now through Friday: A split flow pattern will maintain mild
temperatures for mid-November. Periodic showers are expected to
persist through Wednesday morning. While snow accumulations on
mountain passes will generally be minor with limited travel
impacts, Wednesday morning bears watching. High-resolution models
suggest moderate shower activity around Marias and Lost Trail
passes, which could result in brief snow-covered roadways.
Locally dense valley fog will be a travel concern during the overnight
and morning hours throughout the week. By Thursday and Friday,
weak ridging builds in; this stable atmosphere will likely
facilitate more widespread valley fog.
This Weekend (Nov 22-23): Models continue to shift the upper-
level jet further north compared to earlier runs. If this
northward trend holds, precipitation amounts will further decrease,
and snow levels will rise. The latest NBM indicates 48-hour
precipitation totals of 0.40 to 0.70 inch across the ranges of
northwest Montana, with much lower amounts further south. With
snow levels forecast between 4500 and 5500 feet, road impacts
will likely be confined to minor travel difficulties on higher
passes with the latest snow forecast of 1 to 3 inches. Please stay
tuned as this forecast period evolves.
Thanksgiving Week: The pattern signals a transition to more
widespread, impactful wintry weather. High confidence remains that
a trough and cold front arriving later Monday into Tuesday will
deliver the coldest air so far this season. However, recent trends
suggest this trough may not be as deep as previously forecast,
which would initially limit valley snow accumulation.
Despite this, pass-level travel will likely become difficult due to a
combination of slick roads, reduced visibility, and gusty winds. The NBM
currently projects 3 to 7 inches of new snow on the passes, with an inch or
less for lower valleys Monday/Tuesday.
Looking further ahead, the NBM indicates a 60-70% probability of
high temperatures remaining at or below freezing for western
Montana valleys by the middle of next week. While there is still
model divergence regarding the depth of the arctic air, there is
growing support that the core of the coldest air will remain along
the Divide and points east through at least late next week. The
general pattern the second half of next week favors a showery
west to northwest flow, supporting additional snowfall
opportunities. In fact, this is a common setup for periodic
moderate snow showers to reach lower valley locations.
&&
.AVIATION...An unsettled pattern will persist through Tuesday, resulting in
frequent mountain obscurations and periodic low ceilings. Overnight and
morning fog remains a concern in areas where partial clearing occurs,
particularly at KGPI and KMSO.
Shower activity will gradually diminish this afternoon, primarily impacting
northwest Montana. By Tuesday morning, a sharper shortwave will drive a
weak cold front toward the Idaho/Montana border, accompanied by a distinct
band of rain and snow (snow levels near 6500 feet). Precipitation coverage
is expected to decrease as the front tracks eastward later in the
day.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...None.
&&
$$
Office: BYZ
FXUS65 KBYZ 172015
AFDBYZ
Area Forecast Discussion
National Weather Service Billings MT
115 PM MST Mon Nov 17 2025
.KEY MESSAGES...
- Near to above normal temperatures (45-60 degrees) continue
through the weekend.
- Low (10 to 30%) chances for precipitation (mainly rain) through
Wednesday, higher chances (30 to 60%) over the mountains (snow).
- Windy conditions are possible in the Livingston/Big
Timber/Harlowton vicinity Friday night into the weekend.
&&
.DISCUSSION...
This afternoon through Monday...
Unremarkable weather forecast continues this week as a split in
the jet stream pushes weather systems mainly north and south of
the area, a few just grazing our part of the northern Rockies at
times. The only real noteworthy weather element is the persistent
near to above normal temperatures through the forecast, and the
lack of significant snowfall particularly in the mountains.
A broad trof is over the western U.S. this afternoon with 3
distinct meso-circulations embedded within it. The closest one is
moving across Wyoming just north of the Colorado border, wrapping
moisture around the east side and up into far SE Montana. Webcams
show wet roads in the Alzada area and Baker has seen a few periods
of light rain so far today, both with temperatures in the mid 30s.
Soundings in this area show temperatures are warmer above the
surface so not expecting any mixed precipitation this afternoon in
these areas, and precipitation there should end over the next
several hours as the disturbance continues to move out into the
plains.
A few weak impulses will move into western zones this evening and
slowly move east tonight through the day Tuesday. Models are
showing a few areas of light precipitation associated with this
energy, though precipitation chances remain in the 10 to 20
percent range outside of the mountains. May turn out to be little
more than sprinkles at times over the lower elevations.
A northern stream low moves along the Canadian border Tuesday
night and shifts east of the area Wednesday bringing shortwave
ridging and stronger downslope flow to the area for a dry day on
Wednesday for central and eastern zones. Pacific moisture will
persist over the western mountains and foothills for continued
low (20 to 40%) precipitation chances there, and this may be
overdone a bit for our area given the split flow ridging over the
area. In any event any precipitation will be very light, even in
the mountains.
Energy continues to flow south and north of the area Thursday
through Saturday with west to east oriented ridging aloft over the
area. This will keep conditions dry, even in the higher terrain.
By late Friday will see westerly winds aloft increase which will
force surface winds along the western foothills to increase. Gap
winds will pick up Friday night through Saturday morning at least
and may need a wind advisory for the usual gap wind areas. At this
point the US-191 corridor looks windy but not enough for
highlites. Will keep tabs on this through the week.
For the end of the weekend heading into Thanksgiving week the
forecast has become significantly more uncertain. The latest
deterministic GFS has deviated to a strong zonal pattern with
downslope winds keeping dry and warm conditions going, while the
Canadian is continuing to show a cold snowy forecast for the
holiday week starting early Monday. The ECMWF is leaning toward
the Canadian but does show a shift of the colder air a bit further
north and delays it a bit. Given this change will have to wait a
bit to see the ensembles and how they shake out. This could be
just a deterministic wiggle in the forecast that the ensemble
trends don't go toward, but definitely a big deviation to warmer
and drier in the GFS deterministic this morning. Stay tuned
through the week if you have travel plans for the Thanksgiving
holiday. Chambers
.AVIATION...
Expect occasional mountain obscuration due to isolated showers and
low clouds over the mountains to continue through the TAF period.
Patchy fog is possible near all TAF sites (20% chance) tonight
into Tuesday morning. Archer
&&
.PRELIMINARY POINT TEMP/POPS...
Tue Wed Thu Fri Sat Sun Mon
-----------------------------------------------------------
BIL 041/058 036/052 030/052 030/053 034/054 033/051 032/046
22/R 12/R 10/U 00/U 00/N 12/R 23/O
LVM 035/056 034/051 030/053 030/052 032/051 032/049 031/048
22/R 13/R 10/U 00/N 11/N 22/O 33/O
HDN 037/057 034/052 027/052 026/052 030/054 030/051 028/049
22/R 11/B 20/U 00/U 01/B 12/R 23/O
MLS 032/055 035/051 027/049 028/052 031/051 030/050 027/046
12/R 31/B 10/U 00/U 00/B 11/B 12/O
4BQ 034/055 036/052 029/049 030/052 032/051 031/049 029/046
12/R 21/B 10/U 00/U 00/B 11/B 12/O
BHK 029/053 034/051 025/047 026/051 029/049 027/047 024/044
12/B 21/B 10/U 00/U 00/N 11/B 01/B
SHR 035/055 030/053 026/052 025/052 027/052 027/050 025/048
23/R 11/B 20/U 00/U 00/B 12/R 22/R
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
Office: GGW
FXUS65 KGGW 172015
AFDGGW
Area Forecast Discussion
National Weather Service Glasgow MT
115 PM MST Mon Nov 17 2025
.DISCUSSION...
KEY MESSAGES:
- Mild temperatures are expected through the week.
- Light precipitation chances continue through Wednesday.
WEATHER PATTERN OVERVIEW:
The NBM has struggled with precipitation chances today because the
upper level trough pressure gradient that is over the region is
rather weak. Scattered rain and mixed precipitation showers are
moving through this afternoon and will continue off and on through
Wednesday afternoon. Low amounts of precipitation accumulation are
expected. There is a low probability of freezing rain occurring
with a shortwave trough on Tuesday night into Wednesday morning
with any precipitation that does fall.
FORECAST CONFIDENCE & DEVIATIONS:
Increased PoPs for Day 1 through Day 3 and increased winds with
NBM 90 for the local winds from Fort Peck to Vandalia. No other
changes were made.
There is low to moderate (20 to 40 percent) confidence of mixed
precipitation occurring through Wednesday afternoon. There is high
(80 percent) confidence of total precipitation accumulation
remaining below 0.05 inches through Thursday for all of northeast
Montana with this pattern. There is low confidence of freezing
rain occurring through Wednesday afternoon. There is high
confidence temperatures will stay near to slightly above average
through the entire forecast period.
&&
.AVIATION...
Update time: 2100Z on November 17th
Flight Category: VFR
Synopsis: Mid to high clouds are moving across the
region as a weak, broad trough overtakes the region. There is low
to moderate (20 to 40 percent) confidence of rain and snow
showers occurring over the next 24 hours. There is a low
probability of dropping to MVFR conditions with these showers.
Winds: East at 7 to 15 knots, becoming light and variable after
11Z, becoming light west after 18Z.
EQUIPMENT: KOLF's ASOS telecom circuit is down and can not be
dialed into. Therefore, AMD NOT SKED for this TAF until repairs
can be made.
&&
.GGW WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
weather.gov/glasgow
