393
FXUS65 KTFX 161824
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1224 PM MDT Wed Sep 16 2026

.KEY MESSAGES...

 - Showers/thunderstorms arrive in SW MT late Thursday
   morning/early afternoon, then spread northward into central MT
   during the evening.

 - There is the potential for strong storms Thursday through Saturday.

 - Shift to drier and milder conditions beginning Sunday.

&&

.DISCUSSION...

 - Meteorological Overview:

The next upper level trough moves into the area out of the west on
Thursday. Due to the SW flow over central MT, there will be a
resulting unstable airmass that develops. As such, expect rounds of
showers/thunderstorms to begin late Thursday morning/early afternoon
and continue through Saturday, mainly impacting southwest/central
MT. Additionally, there is the potential for these storms to be
strong.

As an upper level ridge develops over the region on Sunday, expect a
shift towards mild and drier conditions. The ridge looks to remain
in place through at least Monday.

For Tuesday and Wednesday, models continue to struggle on finding a
common solution. - ESH

 - Forecast Confidence & Scenarios:

The main concern for the thunderstorms Thu night and Friday will
be how strong will the thunderstorms be. Some storms could produce
strong wind gusts and hail. Instability of CAPE could exceed 1500
j/kg around Helena on Friday. Additionally, the airmass will
remain unstable Thu night for thunderstorms to likely continue
much of Thursday night.

For next Tue...both the GFS/EC models continue to have opposite
solutions, with one model warm/dry...the other model cold/wet.
Thus confidence is low at this time for next Tue. Brusda

&&

.AVIATION...
16/18Z TAF Period

Generally mild and dry conditions expected through the rest of
today. Any lingering low stratus in central and north central MT
will finish clearing by early afternoon. Aside from the potential
for a few showers to pop-up in south central MT between 07Z-11Z,
mild and dry conditions are expected to continue through tonight.
Showers and lower clouds bases will move in beginning late Thursday
morning/early afternoon, mainly impacting SW MT. Additionally,
there will be the potential for thunderstorms in SW MT Thursday
afternoon/evening. -ESH

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  43  74  50  73 /   0   0  30  10
CTB  41  69  47  69 /   0   0  10  10
HLN  45  79  50  75 /   0  10  40  50
BZN  42  78  48  74 /   0  40  30  80
WYS  38  72  40  67 /  10  70  50  90
DLN  43  78  47  71 /  20  40  40  90
HVR  44  78  49  76 /   0   0  10  10
LWT  43  79  50  74 /   0   0  10  40

&&

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

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