088
FXUS65 KTFX 301007
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
407 AM MDT Wed Jul 30 2025

.KEY MESSAGES...

 - Unusually high atmospheric moisture remains in place across
   the region through the rest of the work week with daily
   thunderstorm activity having the potential to produce localized
   high intensity rainfall.

 - Temperatures remain near to slightly cooler than average.

&&

.DISCUSSION...

 - Meteorological Overview:

Early morning satellite imagery shows a fair amount of remnant
mid-high level cloud across the region from yesterday evening`s
convection along with some patchy lower clouds across eastern
portions of central/north-central MT, aided by moist low levels
and easterly flow at the surface. A weak axis of upper level
ridging exists across the area between stronger upper ridging
developing across western Canada and the larger scale ridge in
place across the S-central US. This results in lighter flow aloft
and lower wind shear than previous days and a reduced risk for
organized/severe thunderstorms. Anomalous moisture remains in
place across the region however and daytime
heating/destabilization will lead to widely scattered afternoon
thunderstorm development, primarily across the terrain of central
and southwest MT. Todays thunderstorm coverage and intensity is
likely to be lower than previous days but the risk for localized
heavy rainfall exists for locations where thunderstorms develop.

Anomalous moisture remains across the region Thursday and Friday
with PWAT`s peaking as high as 150% of normal on Friday. Waves
ejecting out of the trough along the west coast will bring some
additional lifting to the area for a greater coverage of
afternoon/evening storms on both days. Wind shear looks to be low
enough to keep the threat for severe thunderstorms minimal while
the risk for localized heavy rainfall will be elevated along with
the increased thunderstorm coverage.

Looking ahead, it appears that the highest PWAT`s will get swept
east of the area this weekend following the wave lifting across
the area Friday night. However, a southwest flow with elevated
moisture content and emebedded disturbances looks to persist with
longer range model ensembles trending toward somewhat deeper
troughing moving onto the west coast early next week, supporting
a continued risk for at least some daily shower/thunderstorm
development through the period with some potential for more
widespread precipitation again Monday and Tuesday. Hoenisch

 - Forecast Confidence & Scenarios:

Terrain heating will be the main driver of thunderstorm
development today with low shear and light steering flow likely
to keep thunderstorm activity near the mountains through late this
afternoon before a subtle disturbance lifts out of Idaho and may
shift some thunderstorm activity off the terrain across southwest
MT before diminishing tonight. Main concern here will be the
potential for a few individual storms be anchored in one location
with locally heavy rainfall. Hoenisch

&&

.AVIATION...
30/06Z TAF Period

Showers and isolated thunder will continue to wind down over the
next few hours. There is a low chance for patchy fog and low
ceilings at terminals (20% chance) across North-Central MT in the
morning. Scattered showers and thunderstorms develop late
Wednesday afternoon through the evening across Southwest MT. Main
hazards will be lightning and locally heavy rainfall. Confidence
for showers and thunderstorms decreases moving further north into
North-Central MT. There will be isolated precipitation but it
will be a "hit or miss" at terminals. -Wilson

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

&&

.HYDROLOGY...

A marginal (5-10%)risk for flash flooding exists across the
region through the next several days due to the potential for
localized heavy rainfall with thunderstorms. Areas of particular
concern for flash flooding impacts include recent wildfire burn
scars and urban locations, where runoff would be enhanced if a
slow moving thunderstorm with heavy rainfall developed. Hoenisch

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  82  57  84  60 /  20  10  10  40
CTB  78  55  78  57 /  10   0  20  40
HLN  82  57  84  59 /  30  30  30  50
BZN  81  51  86  51 /  20  20  40  30
WYS  80  40  80  39 /  50  30  50  20
DLN  81  49  84  48 /  40  30  40  30
HVR  84  57  84  60 /  10   0  10  40
LWT  75  54  78  55 /  30  20  20  40

&&

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

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