761
FXUS65 KMSO 051938
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
138 PM MDT Sun May 5 2024

.DISCUSSION...A well formed closed low pressure circulation is
moving from Oregon into southern Idaho this afternoon. This
feature will continue to travel east over the coming days before
getting wrapped up in a longer wave by Tuesday night. In the
meantime, it will continue to push moisture up from the south.
Snow levels tonight will drop down to about 5000 feet. As a result
of this cool-down and available moisture, snow will grace the
higher roadways of Lemhi County and southwest Montana tonight.
Motorists traveling along Highways 28 and 93 in Lemhi County
tonight and Monday morning should be prepared for a few inches of
snow in the vicinities of Lost Trail Pass and Gilmore Summit.
Backcountry travelers in the Clearwater, Beaverhead, Lemhi, and
southern Bitterroot Ranges should expect wintry conditions and
potential for about 6 to 12 inches of snow by Monday morning over
the higher terrain. Further north, the Missions and Swans will
also see a solid snowfall tonight. A cold front passage later in
the day on Monday will bring gusty west winds to the entire
Northern Rockies.

Windy conditions will continue on Tuesday as a longer wave
amplifies over the Northern Rockies. Strong low pressure east of
the Continental Divide will bring wraparound moisture to the
Divide in the Glacier National Park vicinity including Marias
Pass. This scenario will be favorable for snow in these areas
above about 4000 to 5000 feet. Current guidance is showing about 3
to 6 inches for Marias Pass by Wednesday morning. Neighboring
peaks of the Mission, Swan, and Flathead Ranges, as well as the
high terrain of Glacier Park, will see closer to a foot or more.

High pressure develops over the region on Thursday with good
agreement among ensemble solutions to last into the weekend.

&&

.AVIATION... Rain shower activity is increasing from south to
north this afternoon. Precipitation intensity will increase this
evening, resulting in periods of low visibility and ceilings
after about 06/00z. Wind direction will gradually turn westerly by
Monday morning. Precipitation will transition to a rain-snow mix
overnight tonight. Expect precipitation to obscure terrain
throughout the Northern Rockies through Monday.



&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...Winter Weather Advisory from 9 PM this evening to noon MDT
     Monday for Eastern Lemhi County.

&&

$$