Red Flag Warning 15, NWS Missoula, MT

Area Forecast Discussion
National Weather Service Missoula MT
246 AM MDT Sat Sep 12 2026

.DISCUSSION...

KEY MESSAGES:

-  Easterly gap winds early this morning, then strengthening late
   tonight into Sunday morning. Anticipate choppy lakes and
   strong canyon winds.

-  Widespread rain and mountain snow above 7,000 feet late tonight
   into early Monday, mainly through central Idaho and northwest
   Montana.

-  Drying and warming conditions by mid-week.

Brisk easterly winds across western Montana will persist through
Sunday morning, with gusts up to 30 mph expected near favored
canyons, along the western slopes of major terrain, and over
regional waters like Flathead Lake. The strongest winds will be
most pronounced this evening into early Sunday morning. Otherwise,
conditions across western Montana and north central Idaho will
remain largely dry and slightly warmer today ahead of an
approaching storm system.

A strong low pressure system will sweep across the region late
tonight through Sunday, bringing widespread showers and isolated
thunderstorms. The storm's northern track favors the heaviest
precipitation across north-central Idaho and northwest Montana,
where half an inch to over an inch of rain is forecast. Snow
levels will fall to around 7,000 feet by Sunday night in these
areas. Backcountry recreationists should prepare for cold, wet,
and raw conditions that will significantly increase the risk of
hypothermia for anyone caught unprepared. Further south and east,
including the Missoula area, precipitation amounts will be notably
lighter. Southwest Montana will remain mostly dry with gusty
westerly winds, resulting in near-critical fire weather
conditions.

The system will depart to the east by Tuesday, transitioning the
region to a generally warmer and drier weather pattern through
mid-week. Despite the overall drying trend, a few weak atmospheric
disturbances may still trigger isolated, light showers. Tuesday
morning has the potential to be quite chilly, particularly in the
higher valleys of southwest Montana and along the Continental
Divide, where clearing overnight skies may allow temperatures to
drop sharply.

&&

.AVIATION...VFR conditions will generally prevail today across
western Montana and north central Idaho ahead of an approaching
low-pressure system. However, aviation operations will be impacted
by brisk easterly winds developing and peaking this evening into
early Sunday morning. These winds will produce gusts up to 30 mph
near favored canyons and western terrain slopes, likely inducing
localized mechanical turbulence and potential low-level wind
shear. Flight conditions are expected to deteriorate late tonight
through Sunday as widespread showers and isolated thunderstorms
overspread the airspace. This incoming system will lead to
widespread mountain obscurations and prolonged periods of MVFR to
IFR ceilings and visibilities, with the most significant flight
impacts concentrated over north-central Idaho and northwest
Montana where the heaviest precipitation is forecast.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Fire Weather Watch from Sunday afternoon through Sunday evening
     for East Beaverhead.

ID...None.
&&