Shelby, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

346
FXUS65 KTFX 142034
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
234 PM MDT Thu Aug 14 2025

.KEY MESSAGES...

 - Widely scattered thunderstorms with gusty winds and little precipitation
   are expected across areas near the Idaho border through early
   this evening.

 - Seasonably warm temperatures are expected this weekend with
   daily thunderstorm chances returning later this weekend.

&&

.DISCUSSION...

 - Meteorological Overview:

The Northern Rockies and MT remain beneath a moderate westerly flow
aloft in between troughing moving east across central Canada and
upper level ridging centered over the Southern US Plains. A cooler
airmass associated with surface high pressure extends from the
Canadian Prairies south across the MT plains, while a warmer and
drier airmass lingers across western and southwest MT. Lingering
instability across far SW MT, along with the stalled frontal
boundary and some trailing jet energy south of the Canadian trough
will focus some isolated to widely scattered thunderstorm
development through early this evening across mainly areas near the
ID border.

Mainly dry and seasonably warm conditions are expected across the
entire area on Friday as upper level ridging progresses east across
SW Canada while the larger scale ridge remains centered over the S-
central US. Late Saturday through early next week the upper flow
across the region becomes more southwesterly as the large scale US
ridge retrogrades westward toward the southern US Rockies while upper
troughing is reestablished near the west coast of Canada. A plume of
Pacific moisture works into the Northern Rockies by late Saturday,
bringing a chance for showers and thunderstorms  with additional
moisture and an embedded disturbance providing a more widespread
coverage of showers and thunderstorms on Sunday. Longer range model
ensembles support the southwesterly flow pattern remaining in place
through at least the first part of next week with most members
migrating the upper ridge further west toward the SW US but more
uncertainty in the eventual progression of the upper trough across
western Canada. This supports a continued risk of daily showers and
thunderstorms but leaves lower confidence in the coverage and
amount of moisture available next week. Hoenisch

 - Forecast Confidence & Scenarios:

Thunderstorms across far southwest MT through this evening will be
hi-based with very dry sub-cloud conditions. This and steering flow
around 30-40kts enhances the risk for strong winds with even weak
convection there. Further north, there is a small amount of Hi-
resolution model members that indicate the potential for a few
isolated showers and thunderstorms to develop across eastern
portions of central MT this evening and even linger through some of
the overnight period. While this is a low probability scenario there
may still be enough trailing upper level jet energy that would
support isolated overnight convection, so the potential cannot be
ruled out. Hoenisch

&&

.AVIATION...
14/18Z TAF Period

Lower cloud across North-Central MT will clear out throughout the
afternoon. Scattered showers and thunderstorms are expected to
develop mainly south of I-90 this afternoon, though there is a low
end chance for isolated showers in North-Central MT. A
north/northeast shift is expected with the movement of the cold
front this evening, with breezy winds across Southwest MT. Smoke
and haze from local and regional wildfires will cause slantwise
visibility issues for KEKS and KWYS during the TAF period. -Wilson

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

&&

.FIRE WEATHER...

Critical fire weather conditions through this evening remain limited
to southwest MT where lingering hot, dry and windy conditions persist
today along with the risk of thunderstorms with gusty/erratic winds
and little precipitation. Some improvement is expected through the
weekend with slight moderation in temperatures there along with less
windy conditions, however breezy afternoon winds and low humidity
will maintain an elevated fire weather risk. Hoenisch

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  53  87  57  91 /   0   0   0   0
CTB  50  79  54  82 /   0   0   0   0
HLN  55  89  57  90 /   0   0   0  10
BZN  51  90  53  91 /   0   0   0  10
WYS  41  82  42  81 /  20  10  10  20
DLN  47  87  50  87 /   0  10   0  20
HVR  53  85  57  91 /  20  10  10   0
LWT  52  83  56  87 /  10  10   0  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
&&

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