326
FXUS65 KTFX 170525
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1125 PM MDT Mon Jun 16 2025

Aviation Section Updated.

.KEY MESSAGES...

 - This afternoon through this evening there will be showers and
   thunderstorms with isolated strong to severe thunderstorms in
   Southwest and Central Montana.

 - This afternoon through this evening there will be showers and
   thunderstorms with isolated strong to severe thunderstorms in
   Southwest and Central Montana.

 - On Friday showers and thunderstorms will return to the area
   with a cool down and widespread precipitation for the weekend.

&&

.UPDATE...
/Issued 832 PM MDT Mon Jun 16 2025/

No major changes were necessary this evening. Latest high
resolution guidance hints at light showers persisting in spots
across Southwest Montana through much of the overnight. Hence,
PoPs were raised a bit to account for this trend. In areas where
cloud cover breaks late tonight, some patchy fog looks to develop.
-AM

&&

.DISCUSSION...
/Issued 832 PM MDT Mon Jun 16 2025/

 - Meteorological Overview:

An upper-level trough will move over North-central, Central, and
Southwestern Montana this afternoon. This will bring scattered
showers and thunderstorms to the area this afternoon through this
evening with strong to severe thunderstorms in Central Montana to
Southwestern Montana. On Tuesday an upper-level shortwave moves over
North-central, Central, and Southwestern Montana. This will bring
another round of scattered showers and thunderstorms to the area on
Tuesday.

On Wednesday and Thursday an upper-level ridge builds in over North-
central, Central, and Southwestern Montana. This will dry out the
area and allow temperatures to warm up a few degrees on Wednesday
and Thursday. On Friday an upper-level trough begins to move over
North-central, Central, and Southwestern Montana. This combined with
a surface cold front moving through Friday evening will bring
showers and thunderstorms to the area Friday afternoon and evening.
On Saturday and Sunday the upper-level trough remains over North-
central, Central, and Southwestern Montana. This will allow
temperatures to cool down to well-below seasonal averages with
scattered showers on Saturday and Sunday. Snow-levels will lower to
allow snow to fall in the mountains of Southwestern Montana and
along the Rocky Mountain Front on Saturday and Sunday.

 - Forecast Confidence & Scenarios:

The Storm Prediction Center (SPC) has issued a Marginal Risk (5%
chance for wind gusts of 58 mph or greater and a 5% chance for hail
1 inch in diameter or greater) for severe thunderstorms this
afternoon for Southern Fergus, Southern Judith Basin, Meagher,
Broadwater, Gallatin, and Eastern Madison Counties. On Tuesday there
is a 15 - 50% chance for thunder across North-central, Central, and
Southwestern Montana east of I-15. On Thursday there is a 30 - 40%
chance for thunderstorms south of the Montana Highway 200/US Highway
87 Corridor between Great Falls and Lewistown. On Friday there is a
35 - 65% chance for thunderstorms across much of North-central,
Central, and Southwestern Montana.

For the overall weather pattern for Friday through the weekend,
there is high confidence in the upper-level trough moving over
Montana on Friday and staying through Sunday. There is high
confidence in showers and thunderstorms on Friday with exact
locations and precipitation amounts uncertain at this time. There is
medium confidence that there will be mountain snow this weekend but
there is low-confidence in how low snow-levels will get. There is
high uncertainty in how cold temperatures will get on Sunday. -IG

&&

.AVIATION...
17/06Z TAF Period

VFR conditions will prevail through the TAF period.

Isolated showers continue to move across southwest Montana and are
expected to last through much of the night. That being said,
confidence is low (<20%) for a shower directly impacting KBZN,
KEKS, or KWYS. Low to mid-level clouds are expected to stick
around across much of southwest and central Montana, however,
should any clearing occur overnight these areas will be
susceptible to fog development through the early morning hours.
Otherwise, no visibility impacts are expected through the night.

For the afternoon, shower/thunderstorm coverage is expected to be
fairly hit-or-miss. There is higher confidence (30-50%) of a
shower impacting KHVR, KLWT, and KWYS and lower confidence
(10-20%) of a shower impacting KHLN, KBZN, and KEKS. Generally the
showers are expected to be light, however, there may be some
isolated stronger storms that develop heading into the late
afternoon/early evening hours. Mountain obscuration will be
localized to where the storms pop up.  -thor


Refer to weather.gov/zlc for more detailed regional aviation
weather and hazard information.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  50  81  49  84 /  20  20   0   0
CTB  47  79  47  78 /  10  10   0   0
HLN  52  82  52  85 /  50  20   0   0
BZN  48  78  46  84 /  40  40   0   0
WYS  37  70  36  74 /  30  30   0   0
DLN  45  75  44  81 /  50  20   0   0
HVR  51  85  52  85 /  10  40  10   0
LWT  46  74  49  77 /  30  40  10   0

&&

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

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