250
FXUS65 KTFX 082042
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
242 PM MDT Mon Jun 8 2026

.KEY MESSAGES...

 - Active, cooler week ahead with daily chances for showers and
   afternoon thunderstorms.

 - Strong winds expected along the Rocky Mountain Front and
   portions of Central Montana on Wednesday.

&&

.DISCUSSION...

 - Meteorological Overview:

An upper-level trough will move into the region on Tuesday
bringing back cooler and wetter to Montana. With snow levels
expected to fall down to around 6,000-7,000 feet, there is a
chance for mountain snow with generally light accumulations
expected. On Wednesday, a mid-level jet sets up over North-Central
and Central Montana bringing gusty winds to the region, especially
along the Rocky Mountain Front and portions of Central Montana
between the Highway 12 and Highway 200 corridors.

Thursday through Saturday, the trough exits the region and northwesterly
flow sets up in its place with the chance for a shortwave or two
passing by through the weekend which will continue to keep things
on the wetter side at least through the remainder of the forecast
period.


 - Forecast Confidence & Scenarios:

Active Pattern This Week:

There are widespread greater than 50% chances for at least 0.10"
across much of the region. The probabilities for at least 0.25"
sit at greater than 90% for the Northern Rockies and the Madison
and Gallatin Ranges. Additionally there is a 30-50% chance for at
least 0.25" for the northern portion of the Hi-Line down into
central Montana including Lewistown. Higher amounts become much
harder to find as there is a 60% of greater than 0.50" along the
higher elevations of the Northern Rockies and the Madison and
Gallatin Ranges but otherwise the probabilities are all less than
20% for the region. With the potential for some isolated to
scattered thunderstorms in the afternoon each day, it is very
possible that isolated areas might receive much higher amounts
than the surrounding areas. But the widespread stratiform
precipitation is expected to remain closer to the probabilities
expressed above.

When it comes to the daily chances for afternoon thunderstorms,
there is currently no real threat for severe weather this week.
Broadly speaking, the CAPE is lacking. Wednesday could be
interesting because with the strong mid-level jet overhead any
thunderstorm could easily pull down some of the higher gusts. But
otherwise no major impacts are expected this week from
thunderstorms.


Snow Tuesday thru Thursday:

There is a chance for snow along the mountains Tuesday evening
through Thursday morning. Overall, significant accumulations are
not expected outside of the higher elevations of Glacier National
Park. Currently there is not enough confidence in impactful
accumulations at and below pass level to warrant any advisories.
However, this will be monitored for future updates in case
anything changes.

The main impact and concern will be for those recreating outdoors.
Especially on Wednesday with the strong winds and the chance for
snow above 6,000 feet, those recreating in the backcountry should
be prepared for difficult conditions.


Strong Winds Wednesday:

Overall the event looks to be broken up into two rounds. The first
will be Wednesday morning through early Wednesday afternoon as
strong westerly winds set up along the Rocky Mountain Front and
further south along the Continental Divide down to MacDonald Pass.
Following that there will be a lull of around 3 to 6 hours in the
mid- afternoon before another mid-level jet moves through more
across Central Montana.

When considering a High Wind Watch for this event the main
uncertainty was the timing. There are some stronger 700mb winds
that arrive as early as midnight on Wednesday. However, without
good mixing, it is unlikely that the winds will be able to make it
down until later in the morning. So that element dictated the
start time of the watch. The end time is also a point of
uncertainty. The Euro was much more robust on the second wave of
winds coming down and this was further backed up by the NAM. But
the GFS was showing a lot less confidence with 700mb winds
generally in the 35-45kt range Wednesday evening into early
Thursday morning. For now, the High Wind Watch is placed over the
timeframe with the greatest confidence. But there is a chance that
it might need to be modified, especially if it is to be upgraded
to a warning.

Additionally, the 3-6 hour time lag between the first and second
rounds of high wind made things a little tricky when trying to
decide watch start and end times. Because of the current level of
uncertainty in the timeframe for these rounds, the decision was
made to have one big watch that covers both events with the
understanding that, if it comes time to upgrade, there is a
possibility that the zones in the watch might need to be split up
to better account for how the timing of the strongest winds is
expected to play out.  -thor


&&

.AVIATION...
08/18Z TAF Period

Low-VFR/VFR conditions are expected through the entire 0818/0918
TAF period, with the exception of the KWYS terminal where MVFR
conditions are expected beyond 09-12z Tuesday. CIGS will begin to
lower through the evening hours tonight from southwest to
northeast as moisture overspreads the Northern Rockies, with
precipitation chances increasing across Southwest Montana between
03-09z Tuesday and Central and North Central Montana between
06-15z Tuesday. Mountains will become increasingly obscured
beyond 03z Tuesday. - Moldan

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  49  69  46  60 /   0  20  10  50
CTB  46  65  42  55 /  10  10  30  70
HLN  50  67  43  59 /  10  70  10  20
BZN  48  66  37  58 /  10  90  80  50
WYS  36  55  28  52 /  70 100  70  70
DLN  46  65  36  58 /  50  60  40  30
HVR  49  74  45  62 /   0  20  20  70
LWT  46  68  40  57 /   0  60  30  40

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
High Wind Watch from Wednesday morning through late Wednesday
night for Big Belt, Bridger and Castle Mountains-Fergus County
below 4500ft-Gates of the Mountains-Helena Valley-Judith Basin
County and Judith Gap-Little Belt and Highwood Mountains-Meagher
County Valleys-Upper Blackfoot and MacDonald Pass.

&&

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