Helena Valley, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

270
FXUS65 KTFX 242336
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
536 PM MDT Fri Jul 24 2026

Aviation Section Updated.

.KEY MESSAGES...

 - Dangerously hot temperatures continue through the weekend,
   with heat peaking on Saturday.

 - Isolated thunderstorms Saturday are expected across Central
   Montana, some of which may produce strong outflow winds.

 - Heat lessens slightly next week, but temperatures still remain
   very warm.

&&

.DISCUSSION...

Upper level ridging will continue to be the dominant weather
feature of our weather over the upcoming week, keeping us
generally warm and dry save for a few opportunities for afternoon
thunderstorms. Heat will continue to be the most widespread hazard
through the weekend as the ridge remains positioned in a way that
keeps us in southwesterly flow aloft. This heat will peak on
Saturday, even as a shortwave moving over Washington will kick off
a few afternoon showers and thunderstorms. More details on the
heat and thunderstorms can be found below in the Confidence and
Scenarios sections.

Temperatures will lessen slightly Sunday as the ridge wanes
slightly, but temperatures will remain hot with most lower
elevations reaching the mid 90s to near 100. Temperatures will
wane slightly further Monday as the ridge continues to wane a bit,
but by Monday the ridge will settle into a state it will more or
less maintain its strength through the remainder of the week. The
main day to day difference will be a few rounds of monsoonal
moisture working through the area, which may allow for afternoon
thunderstorms to pop up. As of now, the best chances for afternoon
thunderstorms outside of today and Saturday will be after
Wednesday, but I would not rule out a storm popping up any day
over the next week.

 - Forecast Confidence & Scenarios:

Heat through Sunday: The ongoing heat wave will continue through
Sunday as the upper level ridge maintains its strength. The main
question will be just how hot does it get during the day, and to
what degree does it cool off overnight. Raw model output seems to
be fairly consistent at keeping lower elevation locations across
the plains near 100 today, 100-107 Saturday, then upper 90s to
near 100 on Sunday. However, there are a few areas of uncertainty.
The first wild card is the lingering smoke over the area. While
it seems to have kept temperatures a bit warmer overnight, it
has not seemed to slow down our warm up today as many lower
elevation locations have shot up to the mid/upper 90s to near 100
as of 3PM with plenty of daytime left for warming. We will see how
it affects our cooldown tonight and temperatures Saturday, but
right now it seems to have more potential to keep us warmer at
night while not affecting the temperature during the day too much.
The other, more significant wild card for Saturday will be some
afternoon convection, which would quickly cool off any areas that
see thunderstorms and/or their outflows, which may keep them from
reaching their true temperature potential provided the storms move
through before mid to late afternoon.

Thunderstorms today and Saturday: Showers and thunderstorms will
remain possible the next two days, today mostly across far
Southwestern Montana, with more widespread thunderstorms possible
on Saturday. Given the very warm and dry environment, any
thunderstorm is liable to produce little rainfall on the ground,
and may also produce strong outflows. This is especially true on
Saturday, when storms will have just enough shear to get
organized, and dry air aloft may help promote processes that
produce downburst winds and their associated outflows. Ludwig

&&

.AVIATION...
25/00Z TAF Period

Isolated thunderstorms will affect far Southwest MT this evening.
There is a less than a 20 percent chance for another round of
thunderstorms towards 6z Saturday between Stanford and Lewistown.
However, there is a good chance for storms over Southwest and
Central MT between 19z Sat and 03z Sun. Some of these storms will
produce strong wind gusts. Smoke continues to reduce visibility
down to about 9 miles at times. That trend will likely continue
for the next few days. Thus distant mountains/passes will be
obscured across the entire CWA through the period. Brusda

&&

.FIRE WEATHER...

A Red Flag Warning is in effect across portions of North-Central
Montana on Friday and Saturday with widespread minimum RH values
below 15%, frequent gusts up to 40 mph, and hot temperatures
expected during this time period. Additionally, isolated
thunderstorms may produce localized strong wind gusts and cloud to
ground lightning, along with very little rainfall. The concern
will be that any fire that starts may be very difficult to
contain. Those who are doing anything that could generate sparks,
including yard work, farming, towing trailers, or other activities
should do everything possible to prevent a spark while traveling
and/or recreating outdoors.

Marginal to elevated fire weather concerns may extend into Sunday
and Monday as well, however confidence in critical conditions is
too low at the moment to issue additional fire weather products at
this time.  -thor/Ludwig

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  65 102  61  97 /   0  10  10   0
CTB  56  97  59  88 /   0   0   0   0
HLN  63  99  61  94 /   0  30  20  10
BZN  61  97  59  96 /  10  40  30  10
WYS  59  86  57  87 /  20  20  10  10
DLN  58  92  56  92 /  10  40  30  10
HVR  62 106  64  99 /   0   0  10   0
LWT  62  98  60  94 /   0  30  20   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 9 PM MDT Saturday for Central and Eastern
Lewis and Clark National Forest Areas-Chouteau and Fergus
Counties-Eastern Glacier/Toole/Central/Eastern Pondera/Liberty-
Hill and Blaine Counties-Lewis and Clark National Forest Rocky
Mountain District-Rocky Mountain Front.

Heat Advisory until 9 PM MDT Sunday for Beaverhead and Western
Madison below 6000ft-Canyon Ferry Area-Eastern Glacier, Western
Toole, and Central Pondera-Eastern Pondera and Eastern Teton-
Eastern Toole and Liberty-Gallatin Valley-Gates of the Mountains-
Helena Valley-Madison River Valley-Meagher County Valleys-
Missouri Headwaters.

Extreme Heat Warning until 9 PM MDT Sunday for Bears Paw
Mountains and Southern Blaine-Cascade County below 5000ft-Fergus
County below 4500ft-Hill County-Judith Basin County and Judith
Gap-Northern Blaine County-Western and Central Chouteau County.

&&

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