Great Falls, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

706
FXUS65 KTFX 221144
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
444 AM MST Sat Feb 22 2025

Aviation Section Updated.

.KEY MESSAGES...

 - Above normal temperatures will continue through much of next
   week across North Central, Central, and Southwest Montana.

 - This warming may potentially lead to localized minor flooding
   due to river ice jams and/or snowmelt runoff, at least into
   early next week.

 - Gusty westerly winds will also persist into early next week,
   with the greatest threat for strong winds at times being over
   the plains through Monday.

 - Pacific moisture in the strong westerly flow aloft will also
   bring periods of snow to the mountains, with the greatest
   accumulation potential being in Glacier National Park.

 - A high pressure ridge will help bring drier and less windy
   conditions for the latter half of next week, along with
   continued mild temperatures.

&&

.DISCUSSION...
/Issued 406 AM MST Sat Feb 22 2025/

 - Meteorological Overview:

A westerly flow aloft over Montana will continue to tap into
Pacific moisture through the weekend into Tuesday, bringing gusty
westerly winds to the plains of North Central and Central Montana,
and periods of low-elevation rain and measurable snow to the
mountains above pass level. A series of weak shortwaves is also
forecast to steadily increase the westerly flow aloft through at
least Monday, which will help keep temperatures above seasonal
averages. Combined with a strong west- to- east surface pressure
gradient over the plains and a strengthening stable layer at ridge
top level, this could cause winds to become strong at times
there. A similarly strong south- to-north surface pressure
gradient over Southwest Montana could also cause winds to become
strong at times through favored valleys, such as the Madison River
valley.

After Tuesday, a high pressure ridge off the Pacific coast is
forecast to strengthen as it moves onshore into the Western United
States. This should help keep the forecast area dry with continued
above normal temperatures. Winds aloft should also be a bit weaker
then, so strong winds are unlikely at this time.

This prolonged period of warm temperatures will also increase the
threat for minor flooding due to snowmelt and potential ice
jamming. Please see the HYDROLOGY section for more details.

 - Forecast Confidence & Scenarios:

Winds through Monday:

A High Wind Warning is in effect for the Northern Rocky Mountain
Front east to around Cut Bank. Sustained winds in the Browning
area reached 50 mph at times yesterday evening, so the Warning was
started right away. Although the NBM model forecast probability
for winds to reach that strong again for the remainder of today is
low, the probability that wind gusts could exceed 75 mph
increases to between 70 and 90 percent there again tonight through
much of Sunday, then again late Sunday night through Monday
morning; therefore, the High Wind Watch also in effect for that
area was extended through that period. Similarly, the probability
that gusts will exceed 55 mph at times over much of the plains,
during that same Watch period is 40 to 70 percent, so the Watch
there was also extended through Monday morning. While
probabilities of similarly strong 55 mph wind gusts is lower over
some portions of the plains, the Watch was also expanded in area
to include most of the plains areas, as probabilistic guidance has
had a difficult time resolving the potential for strong winds
there.

Snow on the Rocky Mountain Front, including Glacier National Park
through Tuesday:

The NBM probabilistic guidance keeps the main threat for
measurable snow in a 24-hour period above mountain pass level
along the Rocky Mountain Front, with a 50 to 70 percent
probability of 4 inches of snow Sunday through Sunday night and
again Monday night through Tuesday. At first glance, this may not
be enough to warrant winter weather highlights, but if the threat
lowers to near pass level, that may need to be reconsidered.

Dry period later next week:

Model clusters are in good agreement in keeping a strong high
pressure ridge over the forecast area for the latter half of next
week, so confidence is moderate to high in a dry and mild period.
-Coulston


&&

.AVIATION...
22/12Z TAF Period

The main concern today will be the gusty winds over North Central
MT. The winds will be strong at times in the Cut Bank area, with
windy conditions elsewhere over North Central MT. Expect mostly
cloudy skies across the CWA through the period. Rain/snow is
expected to affect the western mountain passes through the period.
Brusda

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

&&

.HYDROLOGY...

Warming temperatures through the weekend and the upcoming work
week will lead changes in river ice conditions and an increased
risk of river ice break-up and the potential of ice jams. Lower
elevation snowmelt and still frozen ground could also lead to
some increased runoff into creeks and rivers, adding to the
potential for river ice breakup. Ice jams are unpredictable and
flooding can rapidly occur, so those with interests along
waterways should monitor water levels over the coming week and
take action should flooding occur.

In addition, frozen ground after a prolonged cold period and
melting snow may result in standing water in areas of poor
drainage. This could create difficult access to fields and impact
some rural roads. As temperatures warm further early next week
and the ground begins to thaw, muddy conditions may create
additional impacts. The greatest risk for overland impacts from
snowmelt look to be from eastern portions of Teton and Pondera
counties across portions of Cascade and Chouteau counties and
most lower elevation areas in Judith Basin and Fergus counties,
where water equivalent in the lower elevation snowpack ranges
from around 1.0" to as much as 3.0 to 4.0" in portions of Fergus
county. These areas are also most susceptible to overnight
temperatures remaining near or above freezing this weekend into
early next week. Across southwest MT, there is significant water
content in the snowpack in the Gallatin valley, however melting
will likely be slower with overnight temperatures continuing to
fall below freezing. - Hoenisch

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  46  38  50  40 /  10   0  10  40
CTB  43  34  47  36 /  10  10  20  40
HLN  46  30  47  35 /  10  10  30  60
BZN  41  16  43  22 /  10   0  10  50
WYS  32  10  34  19 /  10  10  60  90
DLN  40  20  42  24 /  10   0  30  40
HVR  46  31  50  34 /   0  10  20  40
LWT  44  31  47  35 /  10   0  20  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
High Wind Warning until 11 PM MST this evening for East Glacier
Park Region-Eastern Glacier, Western Toole, and Central Pondera-
Northern High Plains.

High Wind Watch from this evening through Monday morning 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-Hill County-Judith
Basin County and Judith Gap-Northern High Plains-Southern High
Plains-Southern Rocky Mountain Front-Western and Central
Chouteau County.

&&

$$
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