674
FXUS65 KMSO 271813
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
1213 PM MDT Thu Mar 27 2025

.DISCUSSION...

KEY MESSAGES:

- Gusty winds and isolated thunderstorms this afternoon and
  evening with a cold front.

- A return to a colder, more active weather pattern through most
  of next week with heavy, wet snow in the mountains.

Southwest flow over the region today is causing instability and
potentially some thunderstorms. As this system moved into
Washington and Oregon yesterday, high resolution models were too
strong with the convection. And today we have a lot of cloud cover
which is really slowing down how the atmosphere destabilizes. So
we`re only expecting minor impacts from any convection today. That
being said, there`s quite a lot of wind with this system even
without the thunderstorms, and some otherwise weak showers could
cause those winds to mix down. Current models show a high
probability (greater than 80 percent for most of the region) of
winds gusting over 30 mph this afternoon and evening. In northwest
Montana, those models also show around a 10 percent chance of wind
gusts over 50 mph. Despite the models over doing the
thunderstorms, these probabilities for the wind gusts are very
reasonable, as we commonly get wind gusts like these in the Spring
even with light showers.

Friday will be much cooler as a trough moving into Washington and
Oregon today moves over Idaho and Montana. This will mark a change
to a week or more of cooler, unsettled weather. Snow levels will
start to come down below 5,000 ft late Friday and over the weekend
as the system moves and becomes what we often call a Yellowstone
Low pattern. Lower elevations will receive a rain snow mix or just
rain, while the mountains will pick up several inches of snow. The
southern Mission mountains and the Anaconda Pintlar Mountains will
pickup around a foot of new snow this weekend.


&&

.AVIATION...A low digging off the Pacific Northwest coast is
pushing moisture and instability into our region today. High
resolution models are depicting some convection and thunderstorms
moving into northwest Montana after 27/21Z. The strongest storms
are forecast to affect terminal KGPI 28/00Z and 28/03Z with around
a 10 percent probability of wind gusts in excess of 50 mph. As the
low slowly progresses eastward, it ushers in a return to cool,
showery Spring weather. By Saturday 29/18Z snow levels will come
down low enough that snow accumulation is more than 80 percent
likely at terminal KBTM.


&&

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

$$