Winter Storm Warning 3, NWS Great Falls, MT

Area Forecast Discussion
National Weather Service Great Falls MT
1040 AM MDT Tue Mar 10 2026

Aviation Section Updated.

.KEY MESSAGES...

- Light isolated to scattered snow showers across the region
  Tuesday.

- Widespread, longer duration, strong winds possible late
  Wednesday into Thursday across the region.

- Heavy mountain snowfall will impact the Continental Divide
  during the second half of the week, with lower elevation
  snowfall possible Friday and Saturday.

&&

.UPDATE...
/Issued 520 AM MDT Tue Mar 10 2026/

Morning update has been published, mainly to lower low
temperatures over the plains of North Central Montana where
recent snowfall and ideal radiational cooling has allowed
temperatures to plummet.

&&

.DISCUSSION...
/Issued 520 AM MDT Tue Mar 10 2026/

 - Meteorological Overview:

Zonal flow aloft this week will keep streaming in moisture and
Pacific waves through the weekend and into the beginning of next
week. This will keep persistent snow along the Continental Divide
through the forecast period. better synoptic forcing will allow
for better chances for snow to set up late this week along the
mountains and lower elevations. For the near term forecast for
today, a mini shortwave trough will move through the region
Tuesday. This will produce isolated to scattered brief, snow
showers across the region throughout the day.

Wednesday, westerly flow aloft will keep orographic snow over the
Continental Divide throughout the day. However, strong 700mb
winds and a low pressure system coming from the West Coast will
begin a period of more impactful weather. Starting with
widespread strong winds late Wednesday through Thursday. Mountain
wave activity will be possible overnight Wednesday into Thursday
morning, with a strong pressure gradient developing. Diurnal
mixing kicking in late Thursday morning will allow for the
stronger winds aloft to mix down to the surface. The strong winds
will also bring an elevated risk for wildfire spread if one does
start.

The low pressure system moving in late Wednesday and Thursday
will also bring heavy snow to the Continental Divide. A front
pushing south into MT and stalling across North-Central MT will
help bring snow down to lower elevations. This front
wavering/oscillating through the weekend and continuous warm
moist air over running colder air will continue to bring periods
of impactful snow to the mountains/North Central MT lower
elevations Friday and Saturday. Strong winds late Wednesday night
and into Thursday will also bring the concern for
whiteout/blizzard conditions in the mountains and the Rocky
Mountain Front foothills due to blowing snow. One final push of
the front south Saturday will wind down the impactful snow.

Next week, an upper level ridge builds in over the Western U.S.,
keeping MT on the eastern side. Temperatures look to warm up to
well above normal midweek. There will be additional chances for
precipitation at times due to the northwest flow aloft pattern.

 - Forecast Confidence & Scenarios:

Snow Tuesday:

Weak upper-level forcing will keep snow lighter over Marias Pass
(up to a few inches) and lower elevations. Snowfall accumulations
from snow showers across lower elevations will be more localized,
and above freezing afternoon temperatures will make snow struggle
to accumulate.

Winds Wednesday Into Thursday:

There is a concern for another longer duration and widespread
wind event late Wednesday into Thursday across the region. ECMWF
EFI (Extreme Forecast Index) values range from 0.8-0.95 for most
of the region (the Hi-line has lesser values) for Thursday. The
700mb jet peaks to 75-90kts Thursday morning. Probabilities for 58
mph exceed 60-70% chances across the region, except the Hi-line.
The persistent strong pressure gradient throughout the event
brings a concern for persistent sustained winds. Vegetation
weeekend from last Sunday's wind storm will be impacted in this
upcoming event. One uncertainty that remains is how much blowing
dust occurs Thursday. Recent snowfall across the lower elevations
should help the dust not be as severe as Sunday's wind event.
However, with the higher intensity of the winds, I can't rule out
some blowing dust.

Impactful Snowfall Wednesday Evening Through Saturday:

There remains the concern for impactful heavy snowfall along the
Northern Continental Divide Wednesday through Saturday. Remnant
moisture from the atmospheric river along the Pacific U.S. coast
will bring high amounts of QPF to the Northern Continental Divide.
ECMWF EFI (Extreme Forecast Index) has values reaching 0.70-0.90
and shifted tails contours are between 1-2 over the Continental
Divide Wednesday evening through Friday evening. Friday over
North-Central MT, PWAT values reach to 0.40-0.50", which just
about exceeds the 90th percentile for this time of year. This
combined with the front stalling out, looks to be a sufficient set
up for impactful snow at lower elevations Friday and Saturday.
Over a 72 hour period through Saturday afternoon, there's a 50-70%
chance for 6" of snow across the North-Central MT plains.

Models also show a little bit of instability Thursday, which will
bring periods of moderate to heavy snow along the Continental
Divide. This combined with strong winds along the Rocky Mountain
Front foothills, brings a concern for blizzard conditions to set
up late Wednesday into Thursday. The Day 3 Winter Storm Severity
Index is showing Moderate impacts for Marias Pass and Major
Impacts for U.S. 2 for East Glacier to Browning for blowing Snow
impacts late Wednesday through Thursday. The long duration of the
snow will increase stress on the infrastructure throughout the
event. The heavy snow and strong winds Thursday will also bring
the risk for downed trees and power lines. Traveling in the
mountains/Marias Pass during this time frame will be dangerous to
impossible.

South of the MT Highway 200/Little Belts/Snowys corridor looks to
see a less of an impact from this system due to the region being
south of the stalled front. Impacts across lower elevations will
ultimately be determined based on where that front stalls
Thursday through Saturday, which will have a little variability
this far our still. -Wilson

&&

.AVIATION...
10/18z TAF Period

Primary concern this TAF period will be for diurnally driven winds
through sunset today, with widely scattered snow showers around
over the same timeframe. As winds diminish this evening the risk
for snow showers will also diminish. Mountains will occasionally
be obscured this afternoon and early evening from the snow shower
activity. Gusty winds return late morning or early afternoon
across the region Wednesday. -AM

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  38  21  45  37 /  20  20  10  50
CTB  33  17  38  26 /  30  20  20  70
HLN  38  20  46  37 /  30  20  30  60
BZN  38  14  46  34 /  30  20  10  30
WYS  32   4  35  26 /  50  20  10  50
DLN  35  16  45  34 /  20  20  10  30
HVR  40  19  45  27 /  20  20  10  70
LWT  36  16  41  31 /  40  20  10  50

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
High Wind Watch from Wednesday evening through Thursday
afternoon for Beaverhead and Western Madison below 6000ft-Big
Belt, Bridger and Castle Mountains-Canyon Ferry Area-Cascade
County below 5000ft-East Glacier Park Region-Eastern Glacier,
Western Toole, and Central Pondera-Eastern Pondera and Eastern
Teton-Eastern Toole and Liberty-Elkhorn and Boulder Mountains-
Gallatin Valley-Gallatin and Madison County Mountains and
Centennial Mountains-Gates of the Mountains-Helena Valley-Judith
Basin County and Judith Gap-Little Belt and Highwood Mountains-
Madison River Valley-Meagher County Valleys-Missouri Headwaters-
Northern High Plains-Northwest Beaverhead County-Ruby Mountains
and Southern Beaverhead Mountains-Southern High Plains-Southern
Rocky Mountain Front-Upper Blackfoot and MacDonald Pass-Western
and Central Chouteau County.

Winter Storm Watch from Wednesday evening through Friday
afternoon for East Glacier Park Region-Southern Rocky Mountain
Front.

High Wind Watch from late Wednesday night through Thursday
afternoon for Bears Paw Mountains and Southern Blaine-Fergus
County below 4500ft-Hill County-Northern Blaine County-Snowy and
Judith Mountains.

&&

http://www.weather.gov/greatfalls