FXUS65 KTFX 261725

AFDTFX



Area Forecast Discussion

National Weather Service Great Falls MT

1125 AM MDT Thu Jun 26 2025



Aviation Section Updated.



.KEY MESSAGES...



 - Isolated to scattered showers and thunderstorms are expected

   each afternoon and evening through Saturday. 



 - Some thunderstorms will produce strong wind gusts today.



 - Temperatures trend above seasonal averages early next week 

   with a return to to daily thunderstorm chances by the middle of

   next week. 



&&



.UPDATE...

/Issued 1030 AM MDT Thu Jun 26 2025/ 



An area of clouds and light rain showers continues to push through

the area this morning, mostly in line with the forecast if not

slightly more widespread and longer lasting than forecast. The

impact of these lingering clouds on this afternoon's clouds is a

bit uncertain, so we will see how things develop this afternoon.

Ludwig



&&



.DISCUSSION...

/Issued 1030 AM MDT Thu Jun 26 2025/ 



 - Meteorological Overview:



The Northern Rockies and MT remain under an overall 

zonal/westerly flow aloft into the upcoming weekend with

persistent upper troughing centered in the Gulf of AK sending a 

series mainly weak shortwave and upper level jet impulses from 

the Pacific eastward along the US/Canadian border. A weak frontal 

boundary aloft pushing east across the Rockies early this morning 

will spread clouds and a few light showers across central and 

north-central MT this morning with thunderstorm development across

central ID and west-central MT developing early this afternoon 

and tracking east across north-central and southwest MT later 

this afternoon through early this evening. There is a marginal 

(5-10%) risk for severe thunderstorms this afternoon across 

central/north-central MT, mainly due to strong wind gust 

potential. Weaker disturbances moving through the westerly flow 

will bring additional chances for widely scattered afternoon 

showers and thunderstorms again Friday with more isolated coverage

of any showers/storms on Saturday. In the wake of this series of 

disturbances upper level ridging will build across the interior 

western US later this weekend into early next week, sending 

temperatures above seasonal averages with afternoon maximums 

reaching the upper 80s to around 90s across lower elevation 

locations by Monday and Tuesday. Mainly dry conditions are also 

expected through at least Monday with some moisture return 

bringing an increase in daily shower/thunderstorm chances again by

the middle of next week. 



 - Forecast Confidence & Scenarios:



Primary concern with thunderstorm activity this afternoon will be

strong winds, noting a relatively deep/elevated mix layer still 

in place per the 06z KTFX upper air sounding and mid-level flow 

increasing today, supporting the idea of convection with enhanced

outflow or a more organized cold pool despite only modest

instability. Some uncertainty exists related to how much of this 

deeply mixed boundary layer will remain going into this afternoon 

following mid-level moisture increases and even some light showers

moving across the area this morning. Hi-resolution/convection 

allowing model guidance continues to key on stronger storms within

a corridor of CAPE in the 500-1000 J/kg range from roughly 

southern Lewis and Clark county east through Fergus county this 

afternoon with some higher CAPE potentially pooling east of the 

Little Belts, giving the greatest risk for stronger thunderstorms

across Judith Basin and Fergus counties. Hoenisch



&&



.AVIATION...

26/18Z TAF Period



VFR conditions will prevail across all terminals during this TAF 

period. The primary concern during this TAF period is isolated 

strong to severe thunderstorms between 16/20Z and 17/03Z. All 

thunderstorms will produce small hail, frequent lightning, and 

gusty, erratic winds. The strongest thunderstorms have the potential 

to produce wind gusts in excess of 48 kts. At the end of this TAF 

period at the KGTF, KHLN, and KBZN terminals there is a 20 - 40% 

chance for showers and thunderstorms. During any thunderstorm there 

will be a brief period of mountain obscuration. -IG



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

weather and hazard information.



&&



.PRELIMINARY POINT TEMPS/POPS...

GTF  81  55  80  52 /  40  30  30   0 

CTB  76  55  74  50 /  20  10  10   0 

HLN  80  54  80  52 /  70  30  40  10 

BZN  85  50  85  50 /  30  20  30  10 

WYS  74  39  75  39 /  10  10  20  10 

DLN  79  48  80  47 /  30  10  10   0 

HVR  84  55  83  53 /  20  30  10   0 

LWT  79  52  75  51 /  40  40  50  20 



&&



.TFX WATCHES/WARNINGS/ADVISORIES...

None.

&&



$$

http://www.weather.gov/greatfalls

