837
FXUS65 KMSO 220901
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
301 AM MDT Thu May 22 2025

.DISCUSSION...

KEY MESSAGES:

-  Cool and showery conditions to end the week.

-  Warm and mostly dry north, with thunderstorm potential south
   early next week.

A stronger shortwave disturbance will move across the Northern
Rockies from today through early Friday morning. This system will
bring more persistent rain showers to areas along and south of
I-90 in western Montana, as well as north-central Idaho, including
Lemhi County. Valley locations will have a 2025 percent chance
of receiving up to 0.25 inches of rainfall, while the mountains
will have up to a 60 percent chance. Snow levels will range
between 7,000 and 8,000 feet, so if you have plans to venture into
the high country, take necessary precautions. Showers will also
affect areas north of I-90 in western Montana but be widely
scattered in nature, accompanied by cooler conditions.

Seasonably cool and showery conditions will persist across the
Northern Rockies from Friday through Saturday, as the region
returns to a westerly flow aloft.

Nearly all long-range ensemble models remain in agreement that a
ridge of high pressure will build over the Northern Rockies as
early as Sunday and remain in place through the middle of next
week. This will result in a warming and drier trend, with
afternoon temperatures ranging 10 to 15 degrees above normal by
Sunday or Monday. The ridge will be undercut by a cutoff low,
which looks to push moisture northward by Monday. This increase
in moisture may be enough to produce scattered showers and
thunderstorms each afternoon Monday through Wednesday across the
region.

&&

.AVIATION...A disturbance will bring persistent light to moderate
rain showers to all terminals along and south of I-90 and in
north- central Idaho today. Expect lowering visibility and
ceilings at times between 22/20z and 22/24z.


&&

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

$$