685
FXUS65 KMSO 170820
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
220 AM MDT Mon Jun 17 2024

...Winter Storm to make backcountry travel hazardous today
through Tuesday...

.DISCUSSION...Precipitation is increasing early this morning as a
mid level low works into north-central Idaho and west-central
Montana. Snow levels as of 2am MDT have dropped to around 5500
feet along the Idaho/Montana border, closer to 6000 feet in
Southwest Montana. Snow levels are expected to lower closer to
4500 feet later this morning for much of the area. One exception
will be under the band of heavier precipitation northwest of the
low center, where snow levels could briefly fall to 3500-4000
feet. Precipitation becomes showery (perhaps even a few
thunderstorms) this afternoon with considerable showers
continuing tonight into Tuesday as snow levels remain around
5000-5500 feet.

All in all, the impacts remain the same: Backcountry travel will be
very difficult. Snow on trees could cause breaking branches and
power outages are possible. Hypothermia is also a risk for those
unprepared for the cold and raw conditions.

Models continue to show another disturbance digging south out of
Canada Tuesday morning. This will provide a focus for snow showers
across northwest Montana, particularly in the Glacier Park
region.

Gardeners beware of frost potential on Wednesday morning in
valley locations that see partial clearing. Currently, models
show this clearing from the Mission Valley southward into Lemhi
County. Please stay tuned for the latest low temperature forecast
as sensitive plants may need to be covered.

Model ensembles agree (nearly 100%) on a warming trend for the
rest of the week with scattered afternoon showers each day.
Daytime temperatures peak on Sunday about 15 degrees above normal
(upper 80s western Montana valleys, low/mid 90s for north-central
Idaho).



&&

.AVIATION...Precipitation will increase in coverage this morning
as a mid level low moves into Idaho and western Montana.
Generally, precipitation in the form of rain is expected below
4500 feet. However, there is a potential (20-30% chance) for
localized snow accumulations down to valley floors under a heavier
precipitation band just northwest of the low center this morning,
mainly from west- central Montana into north-central Idaho.
Precipitation turns showery (a few thunderstorms as well) late
today as northwest flow takes over with periods of showers into
Tuesday.




&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Winter Storm Warning until 6 AM MDT Tuesday for
     Bitterroot/Sapphire Mountains...Butte/Blackfoot Region.

     Winter Weather Advisory from 6 AM Monday to 9 AM MDT Tuesday for
     West Glacier Region.

     Winter Weather Advisory from 3 AM to 11 AM MDT Monday for
     Missoula/Bitterroot Valleys.

     Winter Storm Warning from 3 AM Monday to 6 AM MDT Tuesday for
     Potomac/Seeley Lake Region.

ID...Winter Storm Warning until 5 AM PDT Tuesday for Southern
     Clearwater Mountains.

     Winter Weather Advisory until 2 PM MDT Monday for Eastern Lemhi
     County...Western Lemhi County.

&&

$$