669
FXUS65 KTFX 151742
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1142 AM MDT Mon Jun 15 2026

Aviation Section Updated.

.KEY MESSAGES...

 - Trending warmer today and Tuesday.
 - Warm and windy on Tuesday ahead of a cold front that will
   bring some scattered showers and thunderstorms Tuesday night
   into Wednesday morning.
 - Seasonable temperatures return for the end of the week, though
   shower and thunderstorm chances increase towards the weekend.

&&

.DISCUSSION...
/Issued 521 AM MDT Mon Jun 15 2026/

 - Meteorological Overview:

Upper level ridging will continue to build into the Northern
Rockies through the day today, which will bring a return to warmer
temperatures with just a bit of light rain possible in Hill and
Blaine Counties early this morning. Overall, tranquil conditions
should persist across the area until this ridge begins to flatten
later this evening as our next weather system approaches from the
northwest. As this system approaches, a few showers and
thunderstorms are likely to develop along the Hi-Line and
gradually slide southward through the overnight hours, bringing
some light rain before decaying around midnight or so.

Winds will be the main story on Tuesday as our system arrives
into the area, bringing gusty winds to all of North Central and
Southwestern Montana. While winds are expected to remain below our
High Wind Warning criteria (58 mph gusts) for the most part, the
winds will still be somewhat impactful as they will pose some
difficulty for high profile vehicles and any fires that manage to
get started could be somewhat difficult to contain. Winds should
be a bit limited in duration, however, as a cold front coming in
from the north should undercut the strongest winds by the evening
hours, though thunderstorms along the front could help cause some
localized stronger gusts.

Beyond Tuesday, our weather will remain slightly active as the jet
stream remains overhead through Thursday, bringing a few afternoon
showers and thunderstorms to the area each day. Our next chance
for widespread precipitation will arrive Friday night and
Saturday, with multiple upper level troughs and lows coming ashore
the West Coast, bringing increased chances for showers and
thunderstorms. Ludwig

 - Forecast Confidence & Scenarios:

Timing of wind Tuesday:

The leading edge of the strongest winds aloft arrives Tuesday
afternoon. Given the narrow temporal window for the stronger winds
to materialize near the Rocky Mountain Front, and that there is
potential for a the Canadian front to undercut westerly winds, a
High Wind Watch is not being issued at this time. Should the winds
pick up quicker and the cold front arrive a bit later, a High Wind
Watch may become necessary.

Risk for hail Tuesday night:

The most aggressive guidance Tuesday night features MU CAPE on the
order of 500 J/Kg or so across the Hi-Line. Should this materialize,
ample westerly flow aloft would result in enough shear for at least
briefly organized thunderstorms. Large hail would be the main
concern should a stronger storm develop.

Gusty showers Wednesday:

Lingering flow on the order of 40-50 kts aloft look to overlap with
some weak instability Wednesday afternoon east of US-87. Any showers
that form would possess the ability to mix these stronger winds to
the surface. Given the coverage of showers is questionable, it is
too early to determine how impactful Wednesday will be in this area.

Thunderstorms this weekend:

Ensembles are favoring easterly winds over the plains this weekend
into much of the following week. This is typically associated with a
more active period of thunderstorms across the region. Those with
outdoor interests should remain aware of the risk for stronger
thunderstorms beginning this weekend. -AM

&&

.AVIATION...
15/18Z TAF Period

VFR conditions prevail through the TAF period. Light isolated
showers will be possible tonight along the Hi-line late tonight
and into the overnight hours. West winds start to increase Tuesday
morning across all terminals, though winds won`t peak until late
in the day Tuesday. -Wilson

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  80  58  86  49 /   0  10   0  50
CTB  79  58  81  45 /   0  20  10  70
HLN  81  56  86  49 /   0  10  10   0
BZN  78  49  88  47 /   0   0   0   0
WYS  75  38  81  37 /   0   0   0   0
DLN  79  48  86  46 /   0   0   0   0
HVR  78  56  86  47 /  10  30  20  60
LWT  73  51  82  45 /   0  10   0  80

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$
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