Area Forecast Discussion
Issued by NWS Missoula, MT

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FXUS65 KMSO 231058

Area Forecast Discussion
National Weather Service Missoula MT
358 AM MST SUN NOV 23 2014

...Periods of snow and slick road conditions today and tonight on
mountain passes...

...Possible light valley snow tonight...

.DISCUSSION...Weak snow bands under northwest flow aloft will
continue periods of light snow and possibly areas of slick road
conditions through this morning. These bands are expected to
weaken through the morning. Those with travel plans this morning
should be prepared for changeable road conditions, especially over
mountain passes.

The next in a line of weather disturbances will quickly approach
western Montana and north central Idaho this afternoon and
evening. Another round of widespread precipitation will develop,
first in northwest Montana and the Idaho panhandle this afternoon,
sweeping into the rest of central Idaho and west-central/southwest
Montana this evening. Mountains and mountain passes will be the
first to be impacted with accumulating snow, once again degrading
road conditions. This system does have the potential to produce
snow down to the valley floors late tonight into Monday morning,
including for the Missoula/Bitterroot and Flathead/Mission
valleys, which could impact the Monday morning commute. Stay

A brief dry window is expected on Monday before yet another
weather disturbance moves into the region beginning Monday night.
This next system has an impressive moisture tap and could lead to
significant mountain snowfall, possibly lasting into Wednesday.
Precipitation type for valley locations will be a bit trickier as
this system initially starts out cool, but gradually warms with
time. A period of valley snowfall is possible Monday night into
Tuesday night, though exact amounts and placement of best valley
snow will largely depend on how quickly warmer air is able to
infiltrate. Currently, valleys of northwest Montana stand the best
chance of measurable snow.

Forecast models continue to hint at a potentially colder and
snowy pattern developing late this week. Timing of the cold air
and possible over-running precipitation varies significantly
between model solutions, but confidence in this overall pattern
change is beginning to grow. This period will continue to be
monitored closely as travel impacts around the Thanksgiving
holiday are possible.


.AVIATION...Localized snow bands changing over to more widespread
snow showers after 23/1900Z will make for active weather at
terminals today. Snow accumulations of an inch or so for KGPI and
KMSO are possible by 24/0600Z. KBTM and KSMN should see lighter
amounts in this time frame, but still enough to make runways
slick. Snow showers will lower visibilities and ceilings which
will obscure terrain into Monday morning. West winds in the 5 to
15 kt range can be expected in the valleys with this system, with
winds up to 35 kts near ridge tops.


MT...WINTER WEATHER ADVISORY until 7 AM MST Monday Lower Clark
     Fork Region.

     WINTER WEATHER ADVISORY from 11 AM this morning to 7 AM MST
     Monday Potomac/Seeley Lake Region...West Glacier Region.

     Bitterroot/Sapphire Mountains.

     WINTER WEATHER ADVISORY until 11 AM MST this morning
     Butte/Blackfoot Region.

ID...WINTER WEATHER ADVISORY from 10 AM this morning to 6 AM PST
     Monday Northern Clearwater Mountains.

     WINTER WEATHER ADVISORY until 11 AM MST this morning Eastern
     Lemhi County...Western Lemhi County.

     WINTER WEATHER ADVISORY until 6 AM PST Monday Southern
     Clearwater Mountains.


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