Area Forecast Discussion
Issued by NWS Missoula, MT

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FXUS65 KMSO 221056
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
356 AM MST SAT NOV 22 2014

...Difficult travel this morning across western Montana and north
central Idaho due to snow and ice causing slick roads...

...Gusty winds this afternoon and evening...

.DISCUSSION...A very complicated weather scenario continues over
western Montana and north central Idaho this morning. Moderate to
locally heavy snow has developed across most mountain passes this
morning, including Lookout, Lost Trail, Lolo and Marias.
Meanwhile, most valley locations have seen mixed precipitation of
rain, freezing rain and snow. Despite the fact that many valley
locations have actually warmed above freezing overnight, sub
surface temperatures remain cold enough to allow ice to form,
especially on untreated roads, bridges, sidewalks and parking
lots. Between mountain pass snow and areas of ice in valley
locations, road conditions will be less than ideal, and travelers
should use extra caution.

Meanwhile, a strong cold front is currently moving through Idaho
and will move through western Montana this morning. With and
behind this cold front, strong gusty winds are expected to
develop, with gusts up to 40 mph likely, especially across
southwest Montana. This cold front will also allow snow levels to
drop through the afternoon, allowing precipitation to change over
to snow even in most valley locations by afternoon. This being
said, precipitation should become more showery in nature and thus
significant accumulations in the valleys are not anticipated.

Another passing disturbance is expected to move through northwest
flow aloft tonight. This feature looks to affect mainly north
central Idaho, with another round of snow for most locations. Some
of this precipitation could bleed over into west central and
southwest Montana, where even valleys (potentially
Missoula/Bitterroot) could see some light snow into Sunday
morning.

The active weather pattern is expected to continue early next
week. Another round of both mountain and valley snowfall is
possible Sunday night into Monday morning. Forecast models
continue to hint at the potential of some snow banding, so this
part of the forecast will continue to be monitored. Another moist
system is expected for Monday night into Tuesday, gradual warming
aloft will slowly increase snow level, especially by Tuesday
afternoon. However, initially another round of valley snow and
possibly even another bout of freezing rain is possible Monday
night into Tuesday morning.

Unfortunately, clarity has not come to the forecast for the middle
of next week, including for Thanksgiving. Forecast models
continue to alternate between a dry ridge of high pressure and a
potentially cold and snowy pattern. Confidence is low in the
overall weather pattern for this time frame and will be monitored
closely over the coming days.


&&

.AVIATION...Rain, snow, and gusty daytime winds will be concerns
for all terminals over the next 24 hours. Morning rain showers
will turn to scattered snow showers by this afternoon with the
passage of a cold front. Winds of 15 to 20 kts with higher gusts
to 30kt are likely with the frontal passage, which is expected
between 22/1600z and 22/1800z. Light snow accumulations this
evening cannot be ruled out at any terminal, but amounts are
expected to be less than an inch where occurring. Additionally,
reduced visibilities can be expected with snow showers.


&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY until 5 PM MST this afternoon
     Butte/Blackfoot Region.

     WINTER WEATHER ADVISORY until 5 PM MST this afternoon
     Bitterroot/Sapphire Mountains.

     WINTER WEATHER ADVISORY until Noon MST today Missoula/Bitterroot
     Valleys.

     WINTER WEATHER ADVISORY until 5 PM MST this afternoon Lower
     Clark Fork Region.

     WINTER STORM WARNING until 5 PM MST this afternoon
     Flathead/Mission Valleys.

     WINTER WEATHER ADVISORY until 5 PM MST this afternoon West
     Glacier Region.

     WINTER WEATHER ADVISORY until 5 PM MST this afternoon
     Kootenai/Cabinet Region.

     WINTER WEATHER ADVISORY until 5 PM MST this afternoon
     Potomac/Seeley Lake Region.

ID...WINTER WEATHER ADVISORY until 5 PM MST this afternoon Eastern
     Lemhi County...Western Lemhi County.

     WINTER WEATHER ADVISORY until 4 PM PST this afternoon Southern
     Clearwater Mountains.

     WINTER WEATHER ADVISORY until 4 PM PST this afternoon Northern
     Clearwater Mountains.

     WIND ADVISORY until Noon PST today for the Camas Prairie...
     Grangeville and Highway 95 in the Lower Hells Canyon/Salmon
     River Region...Orofino/Grangeville Region.

&&

$$



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