743
FXUS65 KTFX 110226
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
826 PM MDT Wed Sep 10 2025

.KEY MESSAGES...

 - Warm today with a chance for isolated showers and thunderstorms
   this afternoon and evening.

 - Precipitation coverage becomes more widespread Thursday and
   Friday with the potential for locally heavy rainfall across
   north-central and central Montana.

 - More seasonable temperatures will continue through the weekend.

&&

.UPDATE...

Isolated showers and thunderstorms are tracking north/northeast
across primarily N-central MT this evening, where some marginal
instability still exists, though forcing is otherwise fairly weak
with energy lifting out of the Western US trough largely tracking
to the E and W of the area through the rest of this evening/overnight.
Mid-level lapse rates remain high enough to keep some potential
for isolated shower development ongoing through the overnight
period with the next disturbance lifting through the trough
arriving in far SW MT early Thursday morning. Hoenisch

&&

.DISCUSSION...
/Issued 514 PM MDT Wed Sep 10 2025/

 - Meteorological Overview:

With that trough axis continuing to move east across the Western
U.S, increasing moisture and forcing will allow for periodic
precipitation today and Thursday. Showers and a rogue thunderstorm
this morning will continue to lift north across North-Central MT.
There will be a lull in precipitation before another wave of
showers and thunderstorms arrive Wednesday afternoon and evening.
Clearing skies from the morning precipitation will allow for about
~500 J/kg of CAPE to build in. This combined with dry air at the
low levels of the atmosphere will allow for a few storms to
produce gusty winds in addition to brief heavy downpours.

Thursday, better forcing and moisture advects into the region. This
will increase coverage of precipitation starting in the
afternoon. Scattered to widespread showers and thunderstorms will
lift north from Southwest MT through North-Central MT. Deep layer
shear of 30- 40kts will allow for some stronger thunderstorms to
develop if the region builds in enough instability. If it does,
then gusty winds, locally heavy rainfall, and small hail will be a
concern.  some

Models hint at a closed low forming heading into the weekend. This
will keep periods of scattered to widespread precipitation Friday
and Saturday. This will also bring cooler temperatures. Heading
into next week, the ensembles begin to diverge noticeably on the
evolution of the next trough building along the Pacific coast.
Though, an active pattern continues, but details are murky.
-Wilson


 - Forecast Confidence & Scenarios:

Showers/Thunderstorms Today:

Isolated showers and thunderstorms are possible through the
evening hours across the region. The question is whether or not
any of these storms become strong enough to become a problem.
Model soundings show a decent enough environment that if things
get going, there is a potential for some isolated strong wind
gusts across central and north-central Montana.

There are still some differing opinions amongst the models. If
the latest run of the HRRR is to be believed, then the majority of
the convection this afternoon will stay west of the divide and
fail to make it over into our area. The NAM still places some
thunderstorms in our area which could produce some stronger gusty
winds. But overall, the severe weather threat for this afternoon
is pretty marginal.


Showers/Thunderstorms Thursday:

A good portion of how Thursday pans out will hinge on what occurs
during the morning hours. If the morning showers and cloud cover
hang on through most of the morning it will cut into the potential
daytime heating which will limit the overall threat of severe
weather. If skies clear up through the mid morning there is a
potential for some low-end severe thunderstorms across north-
central Montana. Overall, the greater threat and more favorable
environment is further into northeastern Montana so confidence is
not particularly high in impacts for our area. But it will be
something to watch with future updates.  -thor


&&

.AVIATION...
11/00Z TAF Period

Isolated showers and thunderstorms track north through this
evening. These are likely to be primarily focused near the
mountains but cannot rule out some of this activity near SW and
central MT terminals with gusty winds the main threat along with
some local mountain obscuration. VFR conditions prevail otherwise
with variable mid to high level cloud-cover increasing and perhaps
a few showers moving north into SW MT early Thursday morning. A
more robust coverage of showers and thunderstorms is expected
Thursday afternoon in association with a disturbance lifting
north through the area. Hoenisch

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  52  77  53  72 /  30  40  60  60
CTB  50  75  50  72 /  10  40  50  50
HLN  53  77  51  73 /  20  60  50  60
BZN  50  79  44  73 /  10  50  20  40
WYS  40  69  34  67 /  20  60  20  50
DLN  47  74  44  69 /  10  50  20  30
HVR  53  77  54  72 /  20  40  70  60
LWT  54  73  49  71 /  50  70  50  60

&&

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

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