Area Forecast Discussion
Issued by NWS Missoula, MT

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FXUS65 KMSO 111028
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
328 AM MST Sun Dec 11 2016

...ARCTIC FRONT EXPECTED TO BRING ADDITIONAL SNOW, BLOWING &
DRIFTING SNOW, AND BLUSTERY WIND CHILLS BY MONDAY...

.DISCUSSION...
A steady stream of light to moderate snowfall continues for
north-central Idaho and western Montana this morning. Accumulating
snow amounts have not been as significant as the previous event
so far, but locations along the Idaho/Montana border such as Lolo
Pass and Lookout Pass could see significant snow amounts now
through this evening. Increasing instability this
morning/afternoon may also lead to heavier convective snow showers
that would bring locally heavier snow amounts, especially for
northwest Montana and north-central Idaho. Thus, winter weather
advisories remain in effect today for areas receiving additional
accumulating snowfall on top of precedent snowy/icy roadways.

Late tonight into Monday morning, a Canadian arctic airmass will
make its way over the Continental Divide and into northwest
Montana. This front will introduce strong gusty winds and blustery
wind chills such as through Bad Rock Canyon and along the Divide.
Snowfall will continue to be enhanced along this cold air
boundary, particularly in northwest/west-central Montana and
portions of north-central Idaho. These elements combined will
result in treacherous winter driving conditions and areas of
blowing/drifting snow with reduced visibilities. The arctic front
will track southward throughout Monday, and the colder
temperatures will make for challenging snow/ice mitigation efforts
on area roadways.

The snow and wind will taper off Tuesday, but the cold air mass
will remain in place supporting very cold overnight temperatures
by Tuesday night. Locations along the Divide could see significant
sub-zero temperatures during this period.

Another round of very moist air will track northeastward on
Thursday/Friday in front of another very cold air mass. Although
forecast details remain unclear at this time, bitterly cold
temperatures and additional accumulating snowfall are likely to
continue for the Northern Rockies.

&&

.AVIATION...
Light to moderate widespread snow showers will continue for north
central Idaho, the MT/ID border, and much of western Montana
today. KMSO, KGPI, and KSMN are most affected by this moisture
today. Precipitation will keep cloud ceilings low and promote
mountain obscurations and reduced visibilities. Snowfall
intensities may increase later this morning/this afternoon as
instability increases across the area.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory until 11 PM MST this evening
     Bitterroot/Sapphire Mountains...Lower Clark Fork Region.

     Winter Storm Watch from late tonight through Monday evening
     Missoula/Bitterroot Valleys...Potomac/Seeley Lake Region.

     Winter Storm Watch from this evening through Monday evening
     Flathead/Mission Valleys...West Glacier Region.

ID...Winter Weather Advisory until 10 PM PST this evening Northern
     Clearwater Mountains...Southern Clearwater Mountains.

&&

$$


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