178
FXUS65 KTFX 040222
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
822 PM MDT Thu Jul 3 2025

.KEY MESSAGES...

 - This afternoon there will be another round of showers and
   thunderstorms in Southwestern and Central Montana.

 - Friday through Saturday it will cool down with widespread rain
   showers and isolated thunderstorms.

 - Early next week it warms up and will be mostly dry.

&&

.UPDATE...

Minor adjustments were made to the precipitation chances over the
next 24 hours based on the latest NBM guidance with QPF
ultimately staying the same.

A chance for fog was added for some of the valleys of southwest
Montana including the West Yellowstone and Wisdom areas. So long
as the skies clear out, the environment is ripe for fog
development overnight. As of now, fog is not expected to be
widespread enough to warrant any products, however, localized
impactful reductions in visibility should be expected for anyone
traveling through the area early Friday morning.

Otherwise, no major changes to the going forecast.  -thor


&&

.DISCUSSION...
/Issued 521 PM MDT Thu Jul 3 2025/

 - Meteorological Overview:

A cold front will move through North-central, Central, and
Southwestern Montana this afternoon into Friday morning. This will
bring showers and thunderstorms to Central and Southwestern Montana
this afternoon and evening. Some storms will produce strong to
severe wind gusts frequent lightning, and/or small hail. On Friday
an upper-level trough will move over North-central, Central, and
Southwestern Montana. This upper-level trough will remain over the
area on Saturday. This will bring cooler temperatures (below
seasonal averages) and widespread showers and thunderstorms to
North-central, Central, and Southwestern Montana Friday afternoon
through Saturday.

On Sunday zonal flow moves over North-central, Central, and
Southwestern Montana. This will dry out the area and warm
temperatures up to be about seasonal averages. On Monday an upper-
level ridge will build in over North-central, Central, and
Southwestern Montana. This will warm temperatures up a little more
on Monday to be slightly above seasonal averages. The upper-level
ridge remains over North-central, Central, and Southwestern Montana
Tuesday through Wednesday which will allow temperatures to warm up
to well above seasonal averages for Tuesday and Wednesday. Due to
the warm temperatures combined with southwest flow aloft, there is
the potential for afternoon thunderstorms on Tuesday and
Wednesday.

 - Forecast Confidence & Scenarios:

This afternoon and evening there is a 40 - 60% chance for
thunderstorms in Southwestern Montana up to Central Montana. On
Friday there is a 15 - 35% chance for thunderstorms in North-central
Montana and a 40 - 75% chance for thunderstorms in Central to
Southwestern Montana with the highest probabilities in Southwestern
Montana. On Saturday there is a 30 - 60% chance for thunderstorms
across North-central, Central, and Southwestern Montana.

On Friday there is a 50 - 80% chance for a quarter inch of rainfall
across Central and Southwestern Montana. On Friday there is a 20 -
40% chance for a tenth of an inch of rain or greater across North-
central Montana. On Friday the mountains of Southwestern Montana
have a 60% chance for one half inch of rain or greater. On Friday
the lower-elevations of Southwestern Montana have a 20 - 40% chance
for one half inch of rainfall or greater. On Saturday North-central
and Central Montana have a 30 - 60% chance for a quarter inch of
rainfall or greater. On Saturday there is a 15 - 40% chance for a
half inch of rain or greater across North-central Montana. On
Saturday Southwestern Montana has a 30 - 50% chance for a tenth of
an inch of rainfall or greater.

On Saturday there is a 30 - 50% chance for high temperatures of less
than or equal to 70 degrees across North-central, Central, and
Southwestern Montana. On Saturday morning there is greater than a
70% chance for lows of 50 degrees or colder across Southwestern
Montana. On Sunday morning there is greater than a 70% chance of low
temperatures of 50 degrees or colder across North-central, Central,
and Southwestern Montana. On Tuesday across much of North-central
Montana there is greater than a 60% chance for high temperatures of
90 degrees or greater. There is uncertainty in the thunderstorm
potential on Tuesday and Wednesday due to uncertainty in if enough
moisture can be brought into the area to allow enough instability
for thunderstorms to form. -IG

&&

.AVIATION...
04/00Z TAF Period

The main concern is the current thunderstorm activity over
Southwest and Central MT. Lightning and gusty winds will be the
main impact. Most storms will diminish by 06z Fri. However, expect
another round of new storms to develop on Friday afternoon over
Southwest MT, and move northeast towards Central MT by Friday
evening. Overall VFR conditions are expected outside any
thunderstorm activity. Brusda

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

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  54  80  53  72 /   0  50  70  70
CTB  48  75  50  64 /   0  20  60  70
HLN  57  77  53  74 /  10  80  80  70
BZN  53  82  49  77 /  40  90  70  70
WYS  43  71  39  71 /  40  90  50  60
DLN  50  73  45  72 /  30 100  60  60
HVR  54  84  53  71 /   0  10  60  70
LWT  55  80  50  69 /  40  40  80  80

&&

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

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