Helena Valley, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

117
FXUS65 KTFX 262052
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
252 PM MDT Thu Jun 26 2025

.KEY MESSAGES...

 - A few gusty showers and thunderstorms possible this afternoon
   and evening.
 - Gradually drying out and over the weekend with decreasing
   shower activity each day.
 - Temperatures rise early next week.


&&

.DISCUSSION...

 - Meteorological Overview:

An upper level shortwave trough moving through the Northern
Rockies today will kick off a few showers and thunderstorms, some
of which will bring some gusty winds up to 50 or 60 mph with the
strongest of the storms. With this said, the overall coverage and
strength of the storms remains slightly uncertain, as cloud cover
this morning and early afternoon was a bit more stubborn than
forecast, which has prevented the erosion of a cap that may
inhibit storm development across the area.

As we head into the weekend, expect shower and thunderstorm
activity to decrease as our upper level flow becomes more westerly
and eventually gives way to an upper level ridge early next week.
Temperatures will remain steady through the weekend before
increasing next week as the ridge builds into the area.

 - Forecast Confidence & Scenarios:

Main area of uncertainty in the forecast is with thunderstorms
today and whether or not they are able to produce gusty winds in
excess of 60 mph. Current radar and satellite is showing the
storms begin to develop across western Montana, and while I do
expect these to continue to move eastward, their strength and
organization may be hampered by a large area of convective
inhibition (CIN, also known as a capping inversion) that remains
thanks to some stubborn cloud cover earlier in the day. With this
said, DCAPE (a measure of the potential for air to be cooled by
rainfall) is quite high across the region, which indicates that
some sporadic gusts in excess of 50 mph will be possible, even in
the absence of a stronger storm. Ludwig&&

.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  55  81  51  79 /  30  30   0   0
CTB  54  73  49  73 /  10  10   0  10
HLN  54  81  53  79 /  30  40   0   0
BZN  50  85  49  82 /  20  30  10  10
WYS  39  75  40  74 /   0  20  10  20
DLN  49  81  47  81 /  10  20  10  10
HVR  56  83  54  80 /  20  10   0  10
LWT  51  75  51  75 /  50  40  20  10

&&

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

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