533
FXUS65 KTFX 111107
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
507 AM MDT Fri Jul 11 2025

Aviation Section Updated.

.KEY MESSAGES...

 - Cool and dry today, trending warmer this weekend.

 - Transitioning cooler and wetter Monday into Tuesday, lingering
   into Wednesday in some areas.

 - High uncertainty with respect to timing and location of any
   heavier precipitation for early next week.

&&

.DISCUSSION...
/Issued 227 AM MDT Fri Jul 11 2025/

 - Meteorological Overview:

Broad upper level ridging centered off the Pacific coast is slowly
beginning to build across the Northern Rockies in wake of troughing
exiting toward the Great Plains this morning. Although the ridging
is building in, the post-frontal airmass in place at the surface
will keep temperatures near or a touch below average today. A few
instances of patchy fog cannot be ruled out this morning,
especially in areas which saw precipitation yesterday evening. As
the ridge continues building, temperatures trend back above
average for the weekend. Ridging looks to hold on long enough to
keep the region dry through Sunday afternoon.

Heading into Monday, the broad ridging is easily broken down by
troughing moving southeastward from BC and vicinity. A cold front is
expected to move from north to south across the region Monday,
though the timing of this front has been far from consistent at this
time. Nonetheless, the main takeaway for Monday into Tuesday will be
for a transition back to cooler than average temperatures, with
opportunities for a more widespread (Stratiform) type of
precipitation. Additional uncertainty associated with this system
will be discussed further in the confidence and scenarios section.

The area attempts to trend drier and warmer Wednesday and Thursday,
though there remains considerable uncertainty as to how quickly that
will occur. -AM


 - Forecast Confidence & Scenarios:

There are several variables early next week that are yet to be
resolved that will have a significant role in how the Monday-
Wednesday timeframe evolve.

The first is the timing of the cold front on Monday. A slower to
arrive front would result in at least a low-end chance for stronger
showers and thunderstorms across Central and Southwest Montana. A
faster to arrive front would keep these opportunities just across
Southwest Montana.

Additionally, guidance is struggling with how the troughing evolves
across the region. A solution with briefly lower snow levels
features a sharper, more potent trough that moves across the region
Tuesday morning. This sharper trough solution would result in an
opportunity for snow in the high elevations of the Northern Rocky
Mountain Front (Including the east side of Glacier NP). Guidance
that is more broad keeps snow levels higher, but keeps the cooler
temperatures around for longer.

Just how quickly the region warms up and dries out will depend on
whether the troughing is sharper, and thus quicker to exit, or if it
is more broad and lingers.

Overall there are many details that need to be worked out before
confidence in either solution grows. -AM

&&

.AVIATION...
11/12Z TAF Period

Lingering moisture will support patchy fog this morning in areas
that saw precipitation over the previous day or so. Otherwise, with
an upper level ridge beginning to build in, no impacts to aviation
are forecast this TAF period. -AM

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

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  80  54  91  59 /   0   0   0   0
CTB  79  52  85  57 /   0   0   0   0
HLN  83  55  91  59 /  10   0   0   0
BZN  82  49  91  54 /  20   0   0   0
WYS  74  37  82  41 /  10   0   0   0
DLN  77  47  88  51 /  10   0   0   0
HVR  81  53  91  57 /  10   0   0   0
LWT  73  50  85  55 /   0   0   0   0

&&

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

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