Butte-Silver Bow, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

567
FXUS65 KMSO 041925
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
125 PM MDT Mon May 4 2026

.DISCUSSION...

KEY MESSAGES:

 - A backdoor cold front continues to bring cooler temperatures
   and northeast winds of 20 to 30 mph across western Montana
   today and Tuesday.

 - Boaters on Flathead Lake should anticipate choppy conditions
   returning this evening and Tuesday due to gusty northeast
   winds.

 - A warming trend begins Wednesday, though a disturbance will
   bring showers to northwest Montana late Wednesday, followed by
   showers and isolated thunderstorms along the Continental Divide
   on Thursday.


A backdoor cold front will continue to move westward this
evening, bringing increasing north and east winds. By Tuesday,
the upper-level jet stream will orient itself almost directly out
of the north. This creates a tight pressure gradient across the
Northern Rockies, sandwiched between the eastern trough and the
western ridge. Expect the gusty winds to persist throughout
Tuesday, making it feel notably cooler than the actual air
temperature.

Flathead Lake will experience enhanced winds this evening and
Tuesday. Expect an increasing north and east winds, with gusts
reaching 20 to 30 mph, particularly over the open waters of the
south half. These winds will generate chop and potentially
hazardous boating conditions.

By Wednesday, the tight pressure gradient will relax as the ridge
of high pressure to our west expands eastward. This will shut off
the gusty northerly winds and initiate a warming trend, with
western Montana valleys returning to the 70s and the lower valleys
of north-central Idaho pushing into the 80s. However, this will
not be a completely dry ridge. Most guidance indicates a
disturbance will ride over the top of the ridge late Wednesday
into Thursday. This atmospheric forcing will initially trigger
showers across northwest Montana late Wednesday, particularly
impacting the Glacier Park region. As the system progresses on
Thursday, instability will increase slightly, shifting the threat
southeastward and bringing showers and isolated thunderstorms
primarily along the Continental Divide.


&&

.AVIATION...A backdoor cold front will continue to create impacts
for the Northern Rockies airspace. Aviation interests navigating
over the Continental Divide this afternoon will encounter
localized precipitation, mountain obscurations, and terrain-
induced turbulence. For valley and terminal specifics, expect
gusty northeast to east winds this afternoon. KMSO, KGPI, and KBTM
will see gusts of 20 to 30 knots, remaining elevated into the
evening hours (particularly after 2200Z). KHRF will experience a
more northerly wind shift to around 20 knots this afternoon and
evening. These gusty and erratically shifting winds will continue
through Tuesday as the flow becomes more purely northerly. Periods
of turbulence will likely continue through Tuesday along the
Divide due to the tight pressure gradient.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...None.
&&

$$