266
FXUS65 KTFX 240921
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
321 AM MDT Tue Jun 24 2025

.KEY MESSAGES...

 - Temperatures warm back to near or slightly above seasonal
   averages for late June through the upcoming weekend.

 - Isolated to scattered showers and thunderstorms possible each
   afternoon through Saturday.

 - Much warmer temperatures may develop early next week.

&&

.DISCUSSION...

 - Meteorological Overview:

Height rises in the wake of upper level troughing shifting east
across central Canada will allow temperatures to warm back to near
seasonal averages across the area today. Some limited moisture
associated with a weak upper trough lifting out of the Great
Basin may support some afternoon shower and/or thunderstorm
development today, primarily across southwest MT. A low-amplitide
trough moving into the Pacific NW Wednesday gradually shifts
across the Northern Rockies and MT through Saturday, maintaining
a zonal flow across the region with enough moisture and weak
embedded energy for daily isolated to scattered showers and
thunderstorms. Thursday appears to hold the greatest potential
for somewhat greater thunderstorm coverage as a surface trough
shifts east across the region with an embedded shortwave. Upper
level ridging begins to strengthen across the interior Western US
late this weekend through early next week for more pronounced
warming and initially dry conditions likely with the building
warmth through at least Monday.

 - Forecast Confidence & Scenarios:

Light steering flow and wind shear along with limited
moisture/instability today will keep thunderstorm development
isolated and relatively weak. On Thursday, moderate mid-level
westerly flow associated with the shortwave will bring increased
wind shear which may support more organized convection with
primary risk being stronger wind gusts. Longer range ensemble
guidance is in agreement with stronger upper level ridging and
warmth developing early next week, though the longevity of the
ridging becomes uncertain beyond Monday with potential for
increased moisture and thunderstorm chances as early as next
Tuesday from both moisture circulating around the ridge or ahead
of the next trough approaching the Pacific NW. Hoenisch

&&

.AVIATION...
24/06Z TAF Period

VFR conditions will prevail through the TAF period.

Patchy fog is possible this morning along the river valleys of the
plains and the southwest wind protect basins but confidence was
not high enough to include it in any of the TAFs. Otherwise,
expect mostly clear skies in the morning with isolated showers
possible across southwest Montana after 24/20Z.  -thor


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

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  78  50  84  54 /   0   0  10  10
CTB  75  46  80  50 /   0   0  10  10
HLN  79  50  83  54 /   0  10  10  10
BZN  78  45  83  50 /  10  10  10   0
WYS  68  32  72  35 /  20  30  10   0
DLN  73  42  78  48 /  10  10  10   0
HVR  80  49  86  55 /   0   0  10  20
LWT  75  49  78  52 /   0   0  20  10

&&

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

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