362
FXUS65 KTFX 091122
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
522 AM MDT Mon Mar 9 2026

Aviation Section Updated.

.KEY MESSAGES...

 - Strong and gusty winds develop once again from the late morning
   through early evening hours today.

 - Another significant wind event is possible from Wednesday
   night through Thursday night.

 - Heavy mountain snowfall is possible from the end of the work
   week to through the first half of the weekend, especially over
   the Continental Divide.

&&

.DISCUSSION...
/Issued 201 AM MDT Mon Mar 9 2026/

 - Meteorological Overview:

A very active and unsettled pattern characterized by persistent
quasi-zonal flow with embedded waves rippling eastward will bring
daily chances for precipitation, seesawing temperatures, and
numerous days of strong to potentially high winds.

Of particular concern will be the period from Wednesday
afternoon/evening through Saturday morning/afternoon when a plume of
Pacific moisture will stream eastward and over the Northern Rockies.
This plume of Pacific moisture will bring heavy mountain
precipitation, primarily in the form of snow, and strong winds,
particularly from Wednesday night through Friday morning. A cold
front moving south over the plains of Central and North Central
Montana Thursday night/Friday morning will stall near the Central
Montana Island Ranges. Pacific moisture streaming over this stalled
low to mid-level front will provide the focus for precipitation to
end the work week and into the first half of the upcoming weekend
for most of the plains of Central and North Central Montana. Further
to the south across the valleys/mountains of Central and Southwest
Montana periods of mountain snow and strong valley winds will occur
over the same period, with temperatures running some 10 to nearly 20
degrees warmer than over the plains of Central and North Central
Montana. - Moldan

 - Forecast Confidence & Scenarios:

Strong to potential High Winds today (Monday)...

Anomalously strong westerly flow, with H700 winds of between 40-
50kts, will provide additional opportunities for strong and gusty
winds over portions of Southwest through North Central Montana.
ECMWF EFIs of between 0.5-0.8 support a climatologically unusual
period of windy conditions through the day today, with BUFKIT
sounding supporting that the strongest winds will occur from the
late morning through early evening hours (i.e. 16z to 02z). NBM25Pct
wind gusts values, which represent a reasonably low end wind gusts
scenario (75% chance for higher wind gusts or a 25% chance for lower
wind gusts), support gusts of between 35-45 mph across Southwest
through North Central Montana; with NBM75Pct wind gusts values,
which represent a reasonably high end wind gusts scenario (75%
chance for lower wind gusts or a 25% chance for higher wind gusts),
support gusts of between 45-60 mph. While the NBM75Pct values
suggest that a few locations could reach or exceed high wind
criteria current thinking is that these instances would be limited
to a few locations per county. For this reason we will hold off on
issuing any High Wind Warnings for the day today; however, should
wind gusts exceeding criteria become more widespread than current
thinking then a short term High Wind Warning may be needed.

High Winds from Wednesday night through Friday morning...

Another widespread and long duration wind event continues to be of
concern over the period, with H700 winds per NAEFS analysis ranging
from 3 to 5 standard deviations above normal at between 50-90kts.
These wind values, particularly along and south of the MT Hwy 200
corridor, are outside of the CFSR climatology between 06z-18z
Thursday. ECMWF EFIs in excess of 0.8 support the potential for this
wind event to be very unusual to extreme (i.e. somewhat similar to
December 17, 2025 and March 8, 2026). Right now one good thing
within the ECMWF EFIs is the fact that the shift of tails (SOTs),
which would indicate how extreme the top 10% of ensemble membership
is, only has a value of 1. Should these shift of tails climb
further over the succeeding days then a truly extreme and impactful
wind event would be possible.  Given the recent strain infrastructure
and vegetation this event has the potential to be particularly
damaging.

Accumulating Snow from Wednesday evening through Saturday afternoon

The potential for heavy, significant snowfall along the Continental
Divide north of the Montana Hwy 200 corridor continues to be of
concern as a plume of Pacific moisture streams eastward over the
Northern Rockies. ECMWF EFIs in excess of 0.95 exist nearly every
day, with a shift of tails of 3 contouring these areas. NBM25Pct
(reasonably low end) values with respect to snowfall accumulations
along the Continental Divide from 00z Thursday through 00z Saturday
range from  1 to nearly 3 feet, with NBM75Pct (reasonably high end)
values ranging from 3 to 5 feet. Over the plains of Central and
North Central Montana 25Pct values range from 2 to 4 inches while
the 75Pct ranges from 8 to 12 inches. Snow levels and where the cold
front stalls will ultimately impact lower elevation snowfall to end
the work week. - Moldan

&&

.AVIATION...
09/12Z TAF Period

Bands of moderate to at times heavy snow will slowly wind down
over the plains of Central and North Central Montana through
15-18z Monday; however, additional snow showers are possible
beyond 18z along and north of the Hi-Line (i.e. KCTB and KHLN)
through 06z Tuesday. Further south, particularly at the KBZN
terminal, mountain and vicinity snow showers will be possible
through 00z Tuesday; however, confidence in any one shower
directly impacting the terminal is only around a 30% chance.
Otherwise, westerly winds will once again become strong and gusty
between 09/16z and 10/02z, with mountain wave turbulence and
instances of low level wind shear remaining a concern through at
least 03-06z Tuesday.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  43  19  39  22 /  30  10  30  10
CTB  36  13  33  20 /  40  20  30   0
HLN  46  19  37  20 /  40  30  40   0
BZN  46  19  36  14 /  50  20  40  10
WYS  44  18  30   3 /  30  10  50  10
DLN  48  18  35  14 /  10  10  30   0
HVR  41  16  39  18 /  40  30  30  10
LWT  39  17  35  17 /  50  10  60  20

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until noon MDT today for East Glacier
Park Region-Southern Rocky Mountain Front.

Winter Weather Advisory until 9 AM MDT this morning for Bears
Paw Mountains and Southern Blaine-Cascade County below 5000ft-
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-Little Belt and Highwood Mountains-Northern Blaine County-
Northern High Plains-Snowy and Judith Mountains-Southern High
Plains-Western and Central Chouteau County.

&&

$$
http://www.weather.gov/greatfalls