Winter Weather in Idaho, November 23, 2021

Area Forecast Discussion
National Weather Service Missoula MT
339 AM MST Tue Nov 23 2021

.DISCUSSION...Light to moderate snow returns to the Northern
Rockies today, starting across northwest Montana this morning.
Snow will spread southeasterly during the afternoon and evening,
impacting the rest of western Montana and north-central Idaho. The
bulk of the snowfall will fall over the Mountain passes, bring
several inches of snow to areas such Lookout, Lolo and Marias
Passes by tomorrow morning. As for the valleys, around an inch or
less of snow is expected, except for the Seeley/Swan Region where
2 to 4 inches of snow is possible. The valleys across northwest
Montana may see periods of light freezing rain along with snow
around daybreak this morning. After the cold front passes this
evening, there will be a slight chance for a few snow showers,
developing into bands. In this case, a few valleys in west-central
Montana could see slightly more snowfall, along with quickly
changing road conditions during the evening commute. Several
Winter Weather Advisories are in place, and details on the
advisories can be found by visiting our website at
www.weather.gov/missoula.

A short lived ridge of high pressure will build over the region
Thursday, before our next weather system arrives for the weekend.
Widespread mountain snowfall and mostly rain for the valleys will
accompany this disturbance, as snowlevels rise to mountain pass
levels. There is a chance that extreme northwest Montana valleys
(Yaak, Libby, and northern Flathead valleys), could see a wintry
mix during the onset of precipitation Thursday night and early
Friday morning.

Forecast ensembles are advertising another ridge of high pressure
returning to the Northern Rockies for the first half of next week.
Which would bring stable conditions, resulting in fog and/or
stratus forming in the valleys, along with cold pools.

&&

.AVIATION...Light to moderate snow returns to the Northern
Rockies today, starting across northwest Montana this morning.
Snow will spread southeasterly during the afternoon and evening,
impacting the rest of western Montana and north-central Idaho. The
onset of snowfall for KGPI is expected to be around 23/1300Z, with
snow showers continuing throughout the day. Light freezing drizzle
may accompany light snowfall this morning on with the onset of
precipitation. A light mix of rain and snow is expected to arrive
in KMSO later this afternoon, around 23/2000Z. After sunset,
snow showers may develop into bands, bring more moderate snowfall
with low visibility to KMSO and KBTM. Only light accumulations of
under 1 inch is expected for the valleys and aviation sites,
unless snowbands do end up developing.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...     Winter Weather Advisory until 5 AM MST Wednesday
     Bitterroot/Sapphire Mountains...Lower Clark Fork Region.

     Winter Weather Advisory until 11 AM MST this morning
     Flathead/Mission Valleys.

     Winter Weather Advisory until 10 AM MST Wednesday West Glacier
     Region.

     Winter Weather Advisory until 11 AM MST this morning
     Kootenai/Cabinet Region.

     Winter Weather Advisory from 10 AM this morning to 10 AM MST
     Wednesday Potomac/Seeley Lake Region.

ID...Winter Weather Advisory until 4 AM PST Wednesday Northern
     Clearwater Mountains...Southern Clearwater Mountains.

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