Area Forecast Discussion
Issued by NWS Missoula, MT

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FXUS65 KMSO 281059
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
359 AM MST SUN DEC 28 2014

...TRAVEL DIFFICULTIES THIS MORNING DUE TO 1 TO 2 INCHES PER HOUR
SNOW RATES...

...BITTERLY COLD TEMPERATURES STARTING TONIGHT...

.DISCUSSION...

The current weather system continues to evolve this morning in
Idaho and western Montana. An area of snow with embedded
enhancement, including snow bands, will result in periods of
moderate to heavy snow through this morning. Snow rates of 1 to 2
inches or more per hour will result and will also add to travel
difficulties. Road conditions throughout the region range from
snow covered, icy, to reduced visibilities, which is likely to
continue at least through the morning. Widespread light snow will
fall through this afternoon but an arctic boundary will pass
through the region that will enhance snow rates along with blowing
snow and reduced visibilities through this evening. The areas with
biggest impacts from enhanced snowfall, blowing snow, and gusty
winds will be along the divide and through favorable canyons such
as Hellgate and Badrock. Wind chills of 10 to 25 below zero will
also be common in the aforementioned areas through Monday
morning.

Northwesterly flow tonight will keep snow falling through north
central Idaho. There is a chance for additional snow
accumulations through the Camas Prairie tonight so the current
snow advisory may need to be extended.

A very cold airmass will settle over the Northern
Rockies Monday through Thursday. Fresh snow cover will
combine with the cold airmass to cause temperatures to fall
to well below zero for morning lows. In fact, confidence is
high that temperatures will not make it out of the single
digits Tuesday afternoon for most locations. The higher terrain
will gradually begin to warm by mid week with highs in the 20s,
while inversions will keep valleys from warming all that much.

The general trend in the long range is for a snowy and cold
pattern Friday into next weekend but confidence is low as forecast
models continue to struggle with the details. Stayed tuned for
further information as this could evolve into a significant
snowfall event.

&&

.AVIATION...Multiple shortwaves currently passing through the
region will continue to bring widespread aviation impacts to north
central Idaho and western Montana. Low ceilings, obscured terrain,
and lowered visibilities will be common at least through today
area wide. An arctic front will move into western Montana this
afternoon and evening and has the potential to produce gusts up to
35-40 KTS from east- northeast at KGPI. KMSO will also have
increase east winds this evening. Locations along the divide and
at KMSO/KGPI will have periods of very low visibilities from
blowing snow. A mix of snow, blowing snow, and low ceilings and
visibilities will last through tonight.


&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...     WINTER WEATHER ADVISORY until 11 AM MST Monday Butte/Blackfoot
     Region.

     WINTER STORM WARNING until 11 PM MST this evening
     Bitterroot/Sapphire Mountains.

     WINTER WEATHER ADVISORY until 11 AM MST Monday
     Missoula/Bitterroot Valleys.

     WINTER STORM WARNING until 11 PM MST this evening Lower Clark
     Fork Region.

     WINTER STORM WARNING until 11 AM MST Monday Flathead/Mission
     Valleys...West Glacier Region.

     WINTER STORM WARNING until 5 PM MST this afternoon
     Kootenai/Cabinet Region.

     WINTER STORM WARNING until 11 AM MST Monday Potomac/Seeley Lake
     Region.

ID...WINTER WEATHER ADVISORY until 11 AM MST Monday Eastern Lemhi
     County...Western Lemhi County.

     WINTER STORM WARNING until 10 PM PST this evening Northern
     Clearwater Mountains...Southern Clearwater Mountains.

     WINTER WEATHER ADVISORY until 4 PM PST this afternoon Lower
     Hells Canyon/Salmon River Region...Orofino/Grangeville
     Region.

&&

$$



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