Winter Storm Warning 2, NWS Great Falls, MT

Area Forecast Discussion
National Weather Service Great Falls MT
1049 AM MST Thu Jan 9 2025

Aviation Section Updated.

.KEY MESSAGES...

 - Winds will increase this evening along the Rocky Mountain Front
   and adjacent plains and spread to the plains of North-Central
   and Central Montana Friday morning continuing through Friday
   night.

 - There will be primarily mountain and mountain adjacent snow
   Friday evening through Monday morning with the heaviest
   snowfall Saturday evening through Sunday morning.

 - Temperatures will warm up to well-above seasonal averages by the
   middle of next week.

&&

.UPDATE...
/Issued 1037 AM MST Thu Jan 9 2025/
Current forecast is on track. No changes this morning. Brusda

&&

.DISCUSSION...
/Issued 1037 AM MST Thu Jan 9 2025/

 - Meteorological Overview:

Today an upper-level ridge slowly begins to move back over North-
central, Central, and Southwestern Montana. Fog will develop in the
Bozeman-Belgrade area this morning due to clear skies and light
winds. The ridge remains over the area on Friday. There will be a
strong surface pressure gradient over North-central and Central Montana
tonight through Friday which will lead to strong winds tonight
along the Rocky Mountain Front which will spread to the rest of
North-central and Central Montana on Friday. Due to the winds
temperatures will warm up to well-above seasonal averages on
Friday. Friday evening into Saturday morning a surface cold front
associated with an upper-level trough begins to move through the
area. The upper-level trough will remain over North-central,
Central, and Southwestern Montana through Monday. This will bring
cooler temperatures and mostly mountain and mountain adjacent snow
with the highest amounts in northerly upslope areas Friday
evening through Monday morning. An upper-level ridge moves over
North-central, Central, and Southwestern Montana on Tuesday and
will stay over the area through next Thursday. This will warm
temperatures back up to well-above seasonal averages by the middle
of next week with dry conditions.

 - Forecast Confidence & Scenarios:

There is a 60% chance for patchy dense fog to form in the Bozeman-
Belgrade area this morning. Due to low-confidence in clouds clearing
early this morning to allow fog to form, at this time a Dense Fog
Advisory will not be issued. There is a 20% chance for fog to form
in the Helena valley this morning. Due to the low confidence a Dense
Fog Advisory will not be issued.

Thursday evening there is a 50% chance for winds of 55 mph or
greater along the Rocky Mountain Front. On Friday there is a 75 -
95% chance for wind gusts of greater than 75 mph along the Rocky
Mountain Front. On Friday there is a 50 - 70% chance for winds of 55
mph or greater along the plains adjacent to the Rocky Mountain
Front. As a result a High Wind Watch was issued for the Rocky
Mountain Front and adjacent plains from this evening through Friday
night. Across portions of the Montana Highway 200 Corridor, Bears
Paw Mountains, and Sweet Grass Hills there is a 50 - 80% chance for
winds of 55 mph or greater on Friday. As a result of low confidence
in widespread high winds in these areas a High Wind Watch was not
issued at this time. On Saturday there is a 50 - 80% chance for
winds of 55 mph or greater in the Sweet Grass Hills, Bears Paw
Mountains, and portions of Fergus County.

For snow on Saturday there is a 50 - 80% chance for 8 inches of snow
or greater in the Little Belts. On Saturday across most lower-
elevation locations there is a 10 - 40% chance for an inch of snow
or greater. On Saturday there is a 40 - 70% chance for 4 inches of
snow or greater between Belt and Stanford along the Montana Highway
200 Corridor. On Saturday in the Bears Paws Mountains there is a 50%
chance for 6 inches of snow or greater. As a result of this being a
northwest flow event and probabilities not fully matching up with
what can be expected meteorologically, a Winter Storm Watch was
issued from 11 PM Friday to 5 PM Saturday for the Highway 200
Corridor. In addition Winter Storm Watches remain in effect for the
Little Belt, Highwood, Little Snowy, Judith, and Bears Paw
Mountains. On Sunday there is a 50 - 80% chance for 8 inches of snow
or greater in the Little Belts and Little Snowies. On Sunday there
is a 60 - 80% chance for 4 inches of snow or greater across most of
the Highway 200 Corridor east of Great Falls and in the Bears Paw
Mountains. Across most of the rest of Central Montana on Sunday
there is a 30 - 70% chance for an inch of snow or greater. On Monday
in the Little Belts, Highwoods, and Little Snowies there is a 40 -
70% chance for 2 inches of snow or greater. On Monday there is a 30 -
70% chance for an inch of snow or greater along the Montana Highway
200 Corridor. -IG

&&

.AVIATION...
09/18Z TAF Period

Aside from some mist at BZN through noon, expect mainly VFR
conditions across North Central and Southwestern Montana today as
skies clear. Winds will be on the increase overnight tonight,
resulting in some blowing snow across the plains (though no
reductions in visibility are in TAFs at this time) and increased
mountain wave turbulence. Ludwig

Refer to weather.gov/zlc for more detailed regional
aviation weather and hazard information.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  34  21  42  28 /   0   0  10  90
CTB  32  20  39  24 /   0   0  10  80
HLN  34  18  39  28 /   0   0   0  80
BZN  32  11  36  23 /   0   0  10  90
WYS  27   0  23   9 /   0   0  20 100
DLN  30  12  34  20 /   0   0   0  40
HVR  31  15  41  27 /   0   0  10  80
LWT  33  17  43  25 /   0   0  10  80

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
High Wind Watch from 5 PM MST this afternoon through Friday
evening for East Glacier Park Region-Eastern Glacier, Western
Toole, and Central Pondera-Northern High Plains-Southern High
Plains-Southern Rocky Mountain Front.

Winter Storm Watch from Friday afternoon through Saturday
afternoon for Bears Paw Mountains and Southern Blaine-Little
Belt and Highwood Mountains-Snowy and Judith Mountains.

Winter Storm Watch from Friday evening through Saturday
afternoon for Cascade County below 5000ft-Fergus County below
4500ft-Judith Basin County and Judith Gap.

&&

http://www.weather.gov/greatfalls

Preliminary Local Storm Report
National Weather Service Great Falls MT
955 AM MST Thu Jan 9 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0700 PM     Snow             Lewistown               47.06N 109.42W
01/08/2025  M2.0 Inch        Fergus             MT   Trained Spotter

            Additional Snowfall of 2 inches. 10 inches
            on the ground.

&&

ML