Shelby, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

997
FXUS65 KTFX 141958
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
158 PM MDT Sun Jun 14 2026

.KEY MESSAGES...

 - Trending warmer through Tuesday, with most areas remaining dry.

 - Breezy Tuesday into Wednesday ahead of and behind a cold front.

 - Seasonable temperatures to close out the week, with increasing
   opportunities for afternoon and evening showers and
   thunderstorms toward the weekend.

&&

.DISCUSSION...

 - Meteorological Overview:

High amplitude ridging centered along the Pacific coastline is
resulting in a northwesterly flow aloft across the region this
afternoon. This ridging slowly slumps/become flattened heading into
the week, eventually resulting in a breezier stretch Tuesday into
Wednesday. Although the ridging is in place nearby, the nature of
the northwesterly flow aloft is not particularly anti-cyclonic in
nature. Weak perturbations overtopping the ridge will dive southeast
across the region and result in a few showers tonight into early
Monday in the vicinity of Havre, and then again across the Hi-line
and vicinity Monday afternoon and evening. The timing in the
afternoon and evening across the Hi-Line Monday will be more
favorable for thunderstorm development, though instability isn`t
looking that impressive at this time.

More active weather moves in as the ridge is flattened Tuesday.
Initial impact will be for a warm and breezy day Tuesday ahead of a
cold front. The strongest winds aloft don`t look to arrive til later
afternoon Tuesday, which mutes confidence in any higher end winds
materializing. As these stronger winds aloft arrive, the cold front
begins to push in from north to south across the region late
afternoon. There looks to be enough instability around to result in
a few showers and thunderstorms along and behind the front over the
plains Tuesday evening into Tuesday night. Should instability end up
on the higher end of the envelope, a few thunderstorms capable of
producing at least small hail Tuesday night near the Hi-Line would
be a reasonable expectation.

Heading into Wednesday the brisk winds aloft begin to exit, but hold
on over the plains east of US-87. Daytime heating and sufficiently
cool air aloft will result in some showers activity, which would
help mix some of the stronger winds to the surface. Regardless of
the potential for stronger winds, Wednesday does look to be breezy
at the least.

Northwesterly flow aloft largely persists to close out the week.
While neither of Thursday or Friday have overwhelming support for
showers and thunderstorms, weak waves moving through the flow aloft
would support at least isolated showers and thunderstorms those two
days.

Several weaker troughs moving in across the west this weekend will
result in at the least a cyclonic nature to flow aloft. This will
support better coverage of showers and thunderstorms. Should one of
these waves trend stronger, a few stronger thunderstorms would not
be unreasonable this weekend. -AM

 - 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...
14/18Z TAF Period

VFR conditions prevail through the TAF period. Generally, a few
passing high clouds through the TAF period with calmer winds.
Monday morning, there will be a low end chance for light isolated
showers along the Hi-line, but low confidence in impacting KHVR
resulted in it being left out of the TAF. -Wilson

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  45  79  57  85 /   0   0  10   0
CTB  45  78  58  81 /   0  10  30   0
HLN  44  81  56  86 /   0   0  10   0
BZN  39  77  48  87 /   0   0   0   0
WYS  31  75  38  82 /   0   0   0   0
DLN  39  78  47  86 /   0   0   0   0
HVR  46  78  53  84 /  10  20  30  10
LWT  41  72  50  80 /   0  10  20   0

&&

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

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