380
FXUS65 KTFX 191801
AFDTFX
Area Forecast Discussion
National Weather Service Great Falls MT
1101 AM MST Fri Dec 19 2025
Aviation Section Updated.
.KEY MESSAGES...
- Strong, gusty winds peak over central and north-central Montana
and along the Rocky Mountain Front early this afternoon and then
over the southwest later in afternoon and evening.
- Mountain snow will continue through this evening, mostly along
the Continental Divide and over southwest Montana. There will
also be scattered rain and snow showers or squalls over lower
elevations during the cold frontal passage.
- Another round of mountain snow arrives late Sunday into Monday.
- Near to above average temperatures are generally expected, but
Arctic air will brush northern areas later today through
Saturday and again on Monday.
&&
.UPDATE...
/Issued 852 AM MST Fri Dec 19 2025/
The current forecast remains on track for today. The cold front
currently pushing south through North-Central MT this morning
will continue to bring lower elevation rain/mountain snow
showers. As it pushes south along I-90 corridor, precipitation
will turn more into a wintry mix at lower elevations. We will
still have to monitor for the development for snow squalls/heavier
snow/wintry mix showers this morning and afternoon, but best
chances will be along and south of the I-90 corridor. Gusty to
strong winds persist this morning. As a Canadian front moves into
the Hi-line this morning, it will start to undercut these
stronger winds. Winds will decrease behind this front, which may
lead to an earlier cancellation of the high wind warning in
Northern MT this afternoon depending on how quickly they decrease.
Colder temperatures also move in behind the Canadian front.
-Wilson
&&
.DISCUSSION...
/Issued 852 AM MST Fri Dec 19 2025/
- Meteorological Overview:
A broad Pacific trough and attendant cold front will maintain
another day of strong, gusty winds and mountain snow through this
evening. The focus of the strongest winds will shift southward as
the day progresses and the increasingly latitudinal oriented cold
front sags southward.
While snow impacts will primarily be over the mountains lower
elevations may also see some brief locally heavy rain, and snow
showers in the afternoon and evening, particularly over central
and southwest MT. A lobe of Arctic air will also clip northern
areas later this afternoon through Saturday with the longest
residence time along the Hi-Line.
Flat ridging aloft moves over the Northern Rockies Saturday into
Sunday for drier conditions and lighter winds. Moisture streaming
in from west of the Continental Divide will be sufficient for
continued light snow along the immediate eastern slopes of the
Rocky Mountain Front.
The next Pacific trough moves in later Sunday into Monday and
brings another round of mountain snow, along with another shot of
Arctic air over the plains. Mountain snow looks to be on the
lighter side with this more subtle wave and strong winds are
generally not expected.
Southwesterly flow aloft develops Tuesday through Thursday and
brings lighter end mountain snow and near to slightly above
temperatures. The next notable trough looks to arrive heading
towards the middle and end of the work week. More mountain snow
and some Arctic air over the plains can be expected with this
system. - RCG
- Forecast Confidence & Scenarios:
Periods of strong winds through this evening...
Current mesoscale analysis shows a wide swath of 60 to 80 kt H700
westerly flow over the forecast area this morning. Surface
transfer has steadily increased and scattered areas of wind gusts
over 60 mph are being observed over central/north-central and
southwest MT. Upper level winds drop off some later this morning,
but diurnal mixing and a cold frontal passage should maintain
periods of strong winds through this evening with the focus of the
strongest winds slowly shifting southward as the day progresses.
Given the current trend and NBM probabilities for wind gusts
exceeding 55 mph running above 70% for much of the area, the high
wind warnings were expanded to include nearly all of the forecast
area with the exception of northern Hill/Blaine and the western
Beaverhead zones. The Bozeman, Dillon, and Helena areas were
placed in the warning, but it`s important to note that the
occurrence of wind gusts over 60 mph will be far more isolated
than the previous event.
Mountain snow and scattered lower elevation rain/snow
showers/squalls...
Mountain snow will continue through this evening along the Rocky
Mountain Front and over the southwest mountains south of I90. The
inherited winter weather advisories still look good for an
additional 2 to 6 inches of snow through this evening. There will
also be a line of rain and snow showers/squalls that will mostly
impact southwest and central areas along and south of a Lincoln to
Lewistown line. Mountain passes will generally see the most
impacts from this activity including brief periods with reduced
visibility below a half mile and slippery roads. Confidence is
lower for lower elevations such as Helena and Bozeman, mostly
because the colder air aloft may not be in phase with the core of
heaviest precipitation, resulting in rain at the onset. - RCG
&&
.AVIATION...
19/18Z TAF Period
The front will bring a wintry mix to Southwest MT this afternoon
through 19/21z-19/23z. Moderate showers developing along the front
brings a slight chance for IFR visibilities. Gusty winds continue
this afternoon, though the strongest winds have passed across the
North-Central MT plains. In the Southwest, once the front has
passes through, winds will decrease. A Canadian cold front will
bring a short period of IFR clouds to KHVR this afternoon. -Wilson
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 50 26 40 27 / 20 0 0 0
CTB 40 16 35 24 / 10 0 0 0
HLN 47 23 38 20 / 90 0 0 0
BZN 50 18 37 18 / 100 40 0 0
WYS 37 7 26 15 / 100 90 10 20
DLN 49 18 33 17 / 90 30 0 0
HVR 42 3 27 16 / 10 0 0 0
LWT 47 21 35 23 / 40 0 0 0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 6 PM MST this evening for East
Glacier Park Region-Southern Rocky Mountain Front.
High Wind Warning until 6 PM MST this evening for Bears Paw
Mountains and Southern Blaine-Cascade County below 5000ft-East
Glacier Park Region-Eastern Glacier, Western Toole, and Central
Pondera-Eastern Pondera and Eastern Teton-Eastern Toole and
Liberty-Fergus County below 4500ft-Judith Basin County and
Judith Gap-Little Belt and Highwood Mountains-Madison River
Valley-Northern High Plains-Snowy and Judith Mountains-Southern
High Plains-Southern Rocky Mountain Front-Western and Central
Chouteau County.
High Wind Warning until 9 PM MST this evening for Beaverhead and
Western Madison below 6000ft-Big Belt, Bridger and Castle
Mountains-Canyon Ferry Area-Elkhorn and Boulder Mountains-
Gallatin Valley-Gallatin and Madison County Mountains and
Centennial Mountains-Gates of the Mountains-Helena Valley-
Missouri Headwaters-Ruby Mountains and Southern Beaverhead
Mountains-Upper Blackfoot and MacDonald Pass.
Winter Weather Advisory until midnight MST tonight for Gallatin
and Madison County Mountains and Centennial Mountains.
Winter Weather Advisory until 9 PM MST this evening for
Northwest Beaverhead County.
&&
$$
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