484
FXUS65 KTFX 132053
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
253 PM MDT Sun Jul 13 2025

.KEY MESSAGES...

- Isolated storms possible tonight, mainly near the Canadian
  border over the north and near the Idaho border over the south.

- A strong July cold front moves southward through the area on
  Monday afternoon.

- Unseasonably cool Tue and Wed, with a good chance for rain Tue.

- A return to summer like temperatures and mostly dry conditions
  by the weekend.

&&

.DISCUSSION...

 - Meteorological Overview:
A few weak upper level disturbances will move eastward across MT
this evening. There is just enough instability and moisture for a
few thunderstorms to develop near the Canadian border over the
north and near the Idaho border over the South. Any storms should
be short lived.

On Monday, a strong July cold front will move southward through
the CWA. Right now, the front should mostly move southward during
the afternoon hours. If the front is a little faster, afternoon
highs might not be quite as warm as currently forecasted. A few
storms could be on the strong side as well, with the main impact
being strong wind gusts.

For Monday night through Wednesday, expect periods of rain to
develop Monday night over North Central MT and then continue
through Tuesday, before diminishing on Wed. The heaviest precip is
expected to fall north of I-90 from Butte to Bozeman. The forecast
models are agreeing on the wetter solutions, with much of North
Central MT now having a 70 percent chance or higher of 1 inch of
qpf. Temperatures on Tuesday will not rise much, especially over
the north, with afternoon highs in the 50s and 60s. The upper
level trof begins to push east of the CWA by Wednesday, with
precip slowly ending from west to east.

Thursday through Sunday...A northwest flow develops on Thursday,
as warmer air starts to move back into the CWA. There is a chance
for a passing shower/thunderstorm on Thu, mostly over the northern
portions of the CWA. Generally dry conditions expected Friday thru
Sunday, along with a nice warming trend. Any chance for
thunderstorms is generally less than 20 percent for next weekend.

 - Forecast Confidence & Scenarios:
The main concern with the frontal passage on Monday is the timing,
as a faster frontal passage will keep daytime temperatures lower
than currently forecast. Additionally, a faster frontal passage
means less chance for severe storms on Monday.

Again, most of North Central MT now has a 90 percent chance for
0.50 inches of precip and a 70 percent chance to get over 1 inch.
There will be some snow in Glacier Park, mainly above 9000 feet,
thus snowfall impacts should be confined mostly to ridge top
areas.

Do expect a windy period, from Monday night into Tuesday,
especially along the Rocky Mountain Front. This will be a north
to east wind, which is a opposite our normal stronger westerly
wind flows. Brusda

&&

.AVIATION...
13/18Z TAF Period

VFR conditions prevail through the TAF period. There will be
isolated showers and thunderstorms across the MT/Canadian border
and the ID/MT border this afternoon and evening. However,
confidence remains low for precipitation to affect terminals
(KCTB/KHVR/KWYS). There is some uncertainty in the timing of the
cold front tomorrow. Some models have the cold front arrive
earlier in the morning tomorrow, which will cause a northerly wind
shift to the northern part of the state. Some hold it off a few
hours later. -Wilson

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

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  60  91  52  56 /  10  20  90  90
CTB  55  76  47  52 /  20  40  90  90
HLN  61  93  55  62 /  10  10  50  80
BZN  55  95  53  69 /  10  10  40  80
WYS  44  84  43  76 /  10  20  20  70
DLN  54  90  50  72 /  10  10  20  70
HVR  58  89  52  62 /  20  20  90  80
LWT  57  88  49  57 /  10  20  70  80

&&

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

&&

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