625
FXUS65 KTFX 172247
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
445 PM MDT Sun Aug 17 2025

Aviation Section Updated

.KEY MESSAGES...

- Scattered showers and thunderstorms are expected this
  afternoon, with gusty winds and a few areas of localized heavy
  rainfall possible.

- Monday`s shower and thunderstorms chances will be more isolated,
  with gusty winds possible with stronger storms.

- Looking mostly dry this week, with a few additional chances for
  precipitation, mainly Wednesday along a cold frontal passage.

&&

.DISCUSSION...

 - Meteorological Overview:

An upper-level shortwave passing through will continue to bring
scattered showers and thunderstorms across Southwest and North-
Central MT this afternoon and evening. The main Heading into
Monday, another shortwave aloft will bring isolated afternoon
showers and thunderstorms. Dry air at the low levels again will
make gusty outflow winds the main hazard with storms.

The upper-level ridge will keep building in the beginning of the
week, which will help bring hot temperatures to the region
Tuesday and Wednesday. Models hint at this upper-level ridge
breaking down Wednesday and Thursday along with a cold front
passage. This cold front will help bring cool down hot
temperatures back to near or slightly below normal through next
weekend. There is a little uncertainty in the timing of the
breakdown of the ridge, and the wind speeds associated with
it/along the front. After this wave passes through, the ridge
still looks to be prominent through next weekend with isolated
chances for precipitation.

 - Forecast Confidence & Scenarios:

Today is looking similar to yesterday`s set up. Dry air at the
surface (deep inverted V profiles) and strong lapse rates with
help bring strong to isolated severe wind gusts across Southwest
MT and parts of North-Central MT. The only limiting factor to this
potential is afternoon temperatures don`t look to be as high as
they were yesterday. This should limit these stronger gusts
overall and to peak to during the late afternoon/early evening
during peak heating. Higher PWATS nearing an inch will have
isolated concerns for locally heavy rainfall under thunderstorms.
The dry air in place again on Monday, gusty winds will be a
concern again for a few stronger storms. However, coverage of
storms look to be less.

The uncertainty in the ridge breaking down/cold front passage
Wednesday and Thursday leaves a few question marks. The first is the
winds. Currently, there`s a 40-70% chance for 40 mph wind gusts
along the Rocky Mountain Front Wednesday and up to 60-80% chance for
25 mph wind gusts everywhere else. If these winds happen along
the frontal passage during the day Wednesday, than it can lead to
elevated fire weather concerns. Along the front Wednesday, there
looks to be an increase in sheer, though there`s uncertainty in
how much CAPE builds in. If sufficient CAPE builds in, then we
will have to watch for strong to severe storms Wednesday. -Wilson

&&

.AVIATION...

18/00Z TAF Period

Scattered showers/thunderstorms will mostly affect Central/Southwest
MT through about 08z before diminishing. Gusty winds/lightning/brief
heavy rainfall will be the main impact. Scattered clouds will reside
over the CWA overnight, with another round of showers/thunderstorms
possible on Monday afternoon. Brusda

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

&&

.FIRE WEATHER...

Elevated fire weather conditions are expected to continue through
today. A mix of wet and dry showers/thunderstorms can produce
strong erratic wind gusts and frequent lightning. This can
lead to new lightning starts and easier fire spread with gusty
outflow winds and lower minimum humidities. -Wilson

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  56  89  59  95 /  20  20   0   0
CTB  50  85  54  90 /   0  10   0   0
HLN  55  89  58  95 /  30  20  10   0
BZN  50  89  53  96 /  40  20  10   0
WYS  40  82  40  86 /  40  10   0   0
DLN  48  86  50  92 /  50  20   0   0
HVR  57  89  60  95 /  10  20   0   0
LWT  53  85  58  91 /  70  20  10   0

&&

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

&&

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