Area Forecast Discussion
Issued by NWS Missoula, MT

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FXUS65 KMSO 242153

Area Forecast Discussion
National Weather Service Missoula MT
253 PM MST TUE NOV 24 2015

...Snow and Blowing Snow and Rapid Freezing of Roads late
this afternoon and this through this evening...

.DISCUSSION...A large low pressure system along the Pacific
Northwest coast has brought moderate to heavy snow showers this
morning and afternoon through northwest and west-central Montana
this morning and afternoon, as well as portions of north-central
Idaho. A Canadian cold front has been dropping southward,
resulting in several inches of snow reported for northwest Montana
and strong and cold, gusty winds. Several road incidents have been
reported near the Kalispell and Flathead Lake areas associated
with snow, low visibility, blowing snow, strong winds, and slick
roads. Chain restrictions were placed along the Divide for
MacDonald Pass. Degraded conditions have also been reported along
Highway 200, Highway 93, and I-90 corridors. Winter storm warnings
and advisories are in effect, and are expected to remain in
effect through Wednesday morning.

As the cold front continues to move down the northern Rockies,
snow showers will also push southward and cold air with strong winds
will take its place. Any wet or slushy roads throughout the day
will become frozen and hazardous in the wake of the cold air
and/or after sunset. This timing is especially significant for
evening commuters in the Missoula and Bitterroot Valleys and
surrounding vicinity. Mountain roads and passes are expected to
have blowing snow through Wednesday morning, which could reduce
visibility and create slick patches despite previously being cleared.
Lingering snow showers will persist for portions of north-central
Idaho, Lost Trail Pass, and southwest Montana through Wednesday

Wind chill factors may dip to 10 to 20 below zero in local areas
where wind will persist tonight, such as Hellgate Canyon (or
downtown Missoula) and Bad Rock Canyon near Columbia Falls.

The next big impact will be VERY COLD TEMPERATURES Thanksgiving
morning and Friday morning. Temperatures will be widespread in the
single digits across much of western Montana. Extreme cold
temperatures anywhere from 10 to 20 below zero are anticipated in higher
valleys. This includes Butte, Georgetown Lake, Philipsburg,
Ovando, and the Seeley/Swan Valley.

Mainly dry conditions are anticipated through the middle of next
week, with the exception of this weekend. Models are indicating a
weather system to our south will produce some wrap around
moisture Saturday and Sunday. If this occurs, a few inches of
snow may be possible along the Divide and southwest Montana.
There is some discrepancy to where this may occur. Given such
uncertainty, some slight chance of precipitation has been
introduced for this weekend in Southwest Montana.

Otherwise expect cold temperatures to remain in the lower valleys.
They will be tough to scour out with the light winds and stable
conditions. The next major system to potentially impact the Northern
Rockies may not occur until late next week.


.AVIATION...A winter storm will continue to affect area terminals
this afternoon and evening. Snow at KGPI will taper off, but
gusty northeast winds will continue into the nighttime hours. For
KMSO, the front and associated wind shift to east winds will
occur this afternoon. Snow is expected to continue through the
evening in west central Montana. For KBTM, snow will likely
increase in intensity after dark, continuing through the
overnight hours. Quickly falling temperatures this evening will
likely cause freezing of any wet runway surfaces. By tomorrow
morning, KBTM and KSMN are expected to see lingering snow showers.
Expect low ceilings and low visibility at times at all terminals
due to snow and blowing snow.


MT...Winter Storm Warning until 5 AM MST Wednesday
     Bitterroot/Sapphire Mountains...Butte/Blackfoot Region...
     Missoula/Bitterroot Valleys.

     Winter Storm Warning until 5 AM MST Wednesday Lower Clark Fork
     Region...Potomac/Seeley Lake Region.

     Winter Storm Warning until 5 AM MST Wednesday Flathead/Mission
     Valleys...Kootenai/Cabinet Region...West Glacier Region.

ID...Winter Weather Advisory until 4 AM PST Wednesday Lower Hells
     Canyon/Salmon River Region...Northern Clearwater
     Mountains...Orofino/Grangeville Region...Southern
     Clearwater Mountains.


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