Patterson, Idaho Weather Forecast Discussion

848
FXUS65 KMSO 121011
AFDMSO
Area Forecast Discussion
National Weather Service Missoula MT
411 AM MDT Fri Sep 12 2025
.DISCUSSION...
KEY MESSAGES:
-  Afternoon and evening showers and thunderstorms are expected
   today, especially focused over the mountains in northwest
   Montana. Threats include gusty outflow winds up to 45 mph,
   localized heavy downpours, small hail, and frequent lightning.
-  Seasonable temperatures this weekend with a fair amount of
   sunshine through Sunday morning.
-  Increasing clouds and a chance for showers on Sunday into
   Monday as another weather system moves through the region.
Another round of scattered showers and thunderstorms are expected
this afternoon and evening. Model guidance continues to show the
heavier showers across the higher terrain of northwest Montana
including the Bob Marshall Wilderness, Glacier National Park,
Salish Mountains and Cabinet Range. This could bring periods of
heavy rain to the Going to the Sun Road. Threats of gusty winds
and lightning will persist. Storms will be more scattered
elsewhere over the Bitterroot Mountains. By tonight and into
Saturday morning, partial clearing combined with moist ground
could lead to patchy valley fog.
By Saturday, the upper low finally shifts into eastern Montana.
Our region will remain under cyclonic flow, supporting scattered
showers and a few isolated thunderstorms, primarily across western
Montana. Sunday may offer a brief lull with some morning sun
before clouds increase ahead of our next approaching weather
system.
Confidence is increasing on another Pacific trough will move into
the region Sunday afternoon into Monday, ushering in another
round of widespread showers and cooler temperatures, and increased
westerly winds.
What has changed in the ensembles? There seems to be more clusters
that support a more digging trough, where the base of it is more
over southern Idaho on Monday. This would favor more widespread
showers across north-central Idaho into southwest Montana, but
less amounts across northwest Montana.
We will continue to monitor this system closely as it develops.
For now, plan on a cool and wet start to the work week.
Thereafter, Tuesday and Wednesday will be very pleasant days with
seasonable temperatures. Ensembles depict a possible ridge-
breakdown next Thursday which could bring breezy winds to the
area.
&&
.AVIATION...Showers and thunderstorms are possible this afternoon
and evening, especially over the mountainous terrain of western
Montana and north-central Idaho. Threats include erratic wind
gusts to 40 knots, heavy rain, small hail and lightning. Shower
activity is expected to wane by 13/0600z. Patchy valley fog along
with lingering lowered ceilings/stratus are possible through
about 13/1400z Saturday morning.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...None.
&&
$$

NWS MSO Office Area Forecast Discussion