812
FXUS65 KTFX 260548
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1148 PM MDT Fri Jul 25 2025

Aviation Section Updated.

.KEY MESSAGES...

 - Daily chances for showers and thunderstorms through the first
   half of the upcoming work week, with each successive day seeing
   better chances for heavier rainfall.

 - Potential for strong to damaging winds with any thunderstorm
   through this evening and then again on Saturday.

 - Near normal temperatures through the weekend and early next
   week.

&&

.DISCUSSION...
/Issued 549 PM MDT Fri Jul 25 2025/

 - Meteorological Overview:

Rest of today through tonight - A subtle wave within
southwesterly flow aloft moving over Northeast Idaho and Southwest
Montana will help to support showers and thunderstorms along and
southeast of a Helena to Lewistown line through the evening hours
tonight. Deep inverted-V`s across Southwest and into portions of
Central Montana through the early evening hours, with cloud bases
near 10-12.5 kft, will help to support strong and erratic wind
gusts beneath any precipitation core; especially those cores that
are collapsing. - Moldan

Saturday through Thursday - Upper-level ridge remains over the
area. This combined with stronger southwest flow aloft and
periodic upper-level shortwaves moving through the upper-level
flow will allow there to be scattered showers and thunderstorms
across North- central, Central, and Southwestern Montana each
afternoon and evening Saturday through Thursday. At least a few
storms will be on the stronger side Saturday through Thursday. Due
to an increase in monsoonal moisture with the southwest flow
aloft there will be a greater coverage of storms on Saturday than
on Friday. Due to an increase in upper-level moisture Tuesday
through Thursday, isolated thunderstorms will have the potential
to produce flash-flooding. The primarily concerns from any
thunderstorm Saturday through Monday will be strong winds and
large hail. Saturday through Thursday temperatures will fluctuate
a few degrees but generally stay around seasonal averages. - IG

 - Forecast Confidence & Scenarios:

Thunderstorms through this Evening :

Primary hazard through the evening hours will be gusty and
erratic outflow winds from thunderstorms across Southwest and
portions of Central Montana. Latest Hi-Res Ensemble Forecast
guidance supports a 20-50% chance for wind gusts in excess of 45
mph beneath any precipitation core through this evening.

Thunderstorms on Saturday :

Initiation, initially along/near the Continental Divide south of
Helena, is expected between 1-3PM on Saturday; with convection then
spreading to the east northeast at 25-35 mph thereafter before
clearing North Central Montana through 9PM-12AM. Primary hazard
during the afternoon and evening hours on Saturday across Southwest
through North Central Montana will be damaging winds in excess of
60 mph, specifically along and southeast of a Hamilton, to
Lincoln, to Great Falls, to Havre line where the probability for
said wind gusts is approximately 5-15% chance. - Moldan

&&

.AVIATION...
26/06Z TAF Period

Mid to high level cloud-cover across the area from earlier showers
continues to dissipate while some localized lower clouds slide
south along the Rocky Mtn Front behind a frontal boundary that
will shift winds to the north at KGTF by 08z. Some of the lower
clouds with CIGS as low as 3000-4000ft may may move into the KCTB
area overnight, otherwise VFR conditions prevail across the
region. Showers and thunderstorms develop across southwest MT
Saturday afternoon, tracking across portions of central and north-
central MT late Saturday afternoon and evening. In addition to
gusty/erratic winds and lightning, some cells could include brief
heavier precipitation and hail.. Hoenisch

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

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  55  86  56  84 /  10  40  40  10
CTB  51  79  50  77 /  10  10  20  10
HLN  56  87  55  86 /  10  40  30  30
BZN  51  90  49  88 /  30  30  30  20
WYS  36  81  37  81 /  10  10  10  10
DLN  46  85  46  83 /  30  40  20  30
HVR  53  87  55  84 /   0  10  40  10
LWT  54  84  53  80 /  30  40  50  20

&&

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

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