Area Forecast Discussion
Issued by NWS Missoula, MT

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FXUS65 KMSO 161312 CCA
AFDMSO

Area Forecast Discussion...CORRECTED
National Weather Service Missoula MT
612 AM MST Mon Dec 16 2019

.DISCUSSION...Snow showers have diminished this morning as high
pressure is developing over the region. Some local morning fog
will occur this morning in the lower valleys. Otherwise, expect a
mix of sun and clouds across the Northern Rockies.

High pressure and inversions will strengthen later today and
tonight. Widespread valley fog will develop early Tuesday morning.
This is setting up to be a pretty strong ridge, so it will be
difficult to weaken valley inversions through Wednesday. As a
result, morning valley fog and low stratus may linger a while
during the day and start earlier at night. The ridge is expected
to weaken late Wednesday as we transition to a more active weather
pattern.

A very moist Pacific air mass will begin to affect the Northern
Rockies Thursday into Saturday. The biggest impact from this
weather pattern will be snow over Lolo, Lookout, and Marias
passes. A couple feet of snow is expected above 4500 feet in
central Idaho and parts west central and northwest Montana.

Expect snow down to the valley floors Thursday. However, snow
levels will gradually rise Friday and Saturday. Precipitation in
the valleys will transition from a mix of rain and snow to all
rain by Friday afternoon. Freezing rain is a possibility across
valleys wherever strong cold pools developed earlier in the week.

A cold front will push through Sunday and Monday. Expect snow
showers across the Northern Rockies with snow levels down to
valley floors.

&&

.AVIATION...Isolated mountain snow showers will dissipate after
16/1500z. Patchy fog is expected to limit visibilities at KMSO
through 16/1600z. Expect overcast skies at KGPI and KSMN today
with with clear skies at KBTM. Patchy fog is expected at all
terminals after 17/1000z.


&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory until 5 AM MST early this morning Lower
     Clark Fork Region.

     Winter Weather Advisory until 5 AM MST early this morning
     Bitterroot/Sapphire Mountains.

     Winter Weather Advisory until 5 AM MST early this morning
     Missoula/Bitterroot Valleys...Potomac/Seeley Lake Region.

     Winter Weather Advisory until 5 AM MST early this morning
     Butte/Blackfoot Region.

ID...Winter Weather Advisory until 4 AM PST early this morning
     Northern Clearwater Mountains...Southern Clearwater
     Mountains.

     Winter Weather Advisory until 5 AM MST early this morning
     Eastern Lemhi County...Western Lemhi County.

&&

$$


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