863
FXUS65 KMSO 171829
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
1229 PM MDT Tue Jun 17 2025

.DISCUSSION...

KEY MESSAGES:

- Warm, dry and breezy conditions through Wednesday.

- Strong thunderstorms, some potentially severe, are possible
  Friday in western Montana and north-central Idaho.

- Increasing confidence in widespread precipitation, cooler
  temperatures, and high-elevation snow this weekend (June 2122).

A weak ridge of high pressure will settle across the western U.S.
through Wednesday, with above-normal temperatures expected into
Thursday. A dry zonal flow will promote plentiful sunshine along
with breezy westerly winds today and Wednesday afternoon, with
gusts of 1525 mph in the valleys and 2530 mph across the higher
terrain.

Showers and thunderstorms will return Thursday across southwest
Montana and Lemhi County as southwesterly flow transports Pacific
moisture and instability into the region. Friday is trending
toward broader coverage of thunderstorms across most of western
Montana and north-central Idaho. Atmospheric conditions ahead of
an incoming cut-off low-pressure system are expected to support
strong thunderstorms, with a few potentially becoming severe. The
main threats will be strong damaging winds, hail, and heavy
rainfall.

Global ensemble models remain in strong agreement that a large
upper-level low will bring much cooler temperatures and increased
chances for widespread precipitation next weekend (June 2122).
Recent guidance has trended toward a closed low solution in the
past 24 hours, with probabilities for 0.50 inches of precipitation
at 80% across northwest Montana and 5060% across the rest of the
Northern Rockies. Models suggest the highest precipitation will
focus across Flathead County, where probabilities for one inch of
precipitation reach 50%, with a 2030% chance for up to two inches
in the terrain around Glacier National Park.

The current forecast snow level suggests accumulating snow down
to 6,000 feet Saturday night into Sunday. Those with plans in the
backcountry and/or high elevations of Glacier National Park should
begin preparing for cold temperatures, accumulating snow, and raw
conditions. Forecast models indicate 2 to 8 inches of snow could
fall around Logan Pass, with a 20% chance of up to one foot in the
higher terrain of Glacier National Park. Moderate to heavy
rainfall in the lower elevations along the Going-to-the-Sun Road
could lead to rock and debris flows. Gardeners should also be
aware of potential frost by Monday morning, especially along the
Divide. Stay tuned!

&&

.AVIATION...VFR conditions are expected under mostly sunny skies
and high pressure. Deep mixing will allow for breezy westerly
winds this afternoon, with gusts of 1520 kts after 17/1900Z.
Wednesday will be very similar, with gusts of 2025 kts.

&&

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

$$