500
FXUS65 KMSO 172013
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
213 PM MDT Thu Jul 17 2025

.DISCUSSION...


KEY MESSAGES:

-  Breezy, warm and dry days are expected through the weekend

-  A few thunderstorms are possible in the Glacier Region,
   Flathead Valley through this evening. Lightning is the main
   threat.

-  20-40% chance for lightning in southeast Lemhi County, Deer
   Lodge and Silver Bow counties Friday afternoon.

-  There`s a 75 percent probability for a cool, wet and breezy
   weather system in northwest Montana on Monday.

There is an upper level wave that is currently moving across the
Canadian Border this afternoon. It has triggered mainly showers
and a few thunderstorms in Glacier National Park. There is a 10
mph lake breeze coming off of Flathead Lake which is keeping the
dewpoints up in the lower to middle 50s. This could support an
isolated thunderstorm in the next several hours from Flathead Lake
to the Glacier Region. This system will also enhance the westerly
breezes today, generally gusting to 25 mph area- wide, but could
see higher gusts to 30 mph from Missoula to points east and
southeast.

Friday, will be the warmest day this week and the weekend, as
highs will reach the 90s across western Montana, and lower 100s in
the lower valleys of north-central Idaho. A wave may initiate a
few thunderstorms across southwest Montana in the afternoon.
Strong wind gusts, heavy rainfall, small hail and lightning would
be the main threats, generally affecting Silver Bow County
southwards. The probability for lightning ranges from 20 to 40
percent in the areas mentioned.

A mostly dry cool front is still on tap to move across the region
Friday night. There could be a few rain drops felt across
northwest Montana Saturday morning, before giving way to a windy
and warm day. There is a 50 to 70 percent chance that wind gusts
could exceed 25 mph across western Montana and Lemhi County. This
could make lakes in those regions, like Georgetown Lake, kind of
choppy and hazardous for small craft. There could be just enough
instability to trigger a few showers or isolated thunder across
northwest Montana in the afternoon.

Sunday will be breezy and warm, but with increasing clouds as a
shortwave trough begins digging south over Washington and Oregon.
As this trough starts to shift eastwards on Monday, breezy
easterly winds and showers/thunderstorms will be on the increase
and could last into Tuesday. There is a 70 to 80 percent chance
that rainfall amounts from this system could exceed 0.09", 48
hours ending Wednesday morning across northwest Montana.

There is a 70 to 80 percent probability that we`ll return back to
a hot pattern, with highs in the 90s (low 100s in north-central
Idaho) by the end of next week.



&&

.AVIATION... A west to southwest flow will develop over the
Northern Rockies today, promoting warm, mostly dry and breezy
conditions across the region. Westerly winds with gusts between
20-25 kts are expected for KMSO, KHRF, KBTM and KSMN this
afternoon by 17/2100Z. Winds are expected to relax after 18/0300Z
this evening. A weak shortwave along the Canadian/US border will
bring a 40 to 60 percent probability for thunder in the Glacier
NP region from 17/2000Z to 18/0000Z.



&&

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

$$