Area Forecast Discussion
Issued by NWS Missoula, MT

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FXUS65 KMSO 252157

Area Forecast Discussion
National Weather Service Missoula MT
257 PM MST WED NOV 25 2015



It`s going to be a cold one the next few nights. Bundle up and
avoid having your pets outside too long. We have an arctic air
mass in place and combined with a healthy several inches of fresh
snowfall, decreasing winds and clearing skies will produce frigid
temperatures the next two nights. The coldest areas will be
typical sheltered and high elevation valleys. Some of the coldest

- Butte, Georgetown Lake, Seeley/Swan Valley and Ovando could all
wake up to temperatures 10 to 20 degrees below zero.

- Missoula, Bitterroot, Flathead, Mission valleys and the valleys
of Northwest Montana will wake up to temperatures the next couple
of mornings in the single digits to 5 below zero.

Winds will be relatively light so wind chills are NOT a concern.

A few snow showers will linger through this evening across
Southwest Montana into Lemhi County with some light accumulations
still possible. Roadways which have melted some today will
refreeze again tonight, so be careful if you will be traveling.

Dry weather will dominate the next several days under high
pressure. The only exception to the dry weather will be an outside
chance of lake-effect snow forming around Flathead Lake mainly
late tonight and again Thursday night. Sudden changes in road
conditions will be possible, if lake-effect snow does develop.

A weather system will pass south of the region late this weekend
bringing the potential for some wrap around moisture across
southwest Montana. Most forecast models suggest this moisture will
remain well to the south and not impact southwest Montana, but if
the moisture does arrive then a few inches of snow would be
possible. Forecast models also differ considerably on the
potential for another weather system by late next week, so for now
cold temperatures will be the main story.

Given all the cold air that will be in place combined with
generally stable conditions and light winds, it will be pretty
difficult to mix out the lower valleys where cold pools are
favorable to set up. This includes the Mission and
Missoula/Bitterroot Valleys. If inversions remain strong any fog
that develops will be slow to lift and temperatures will not
fluctuate much from day to night through a good chunk of next
week. Now confidence for this scenario is low to moderate with
models not showing any significant system in the region until the
middle of next week. Some models actually show this stagnant
pattern through the entire first week of December. Impacts on air
quality may end up being a concern.


.AVIATION...Scattered snow showers in the vicinity of KBTM and
KSMN diminish by mid evening. Expect some mountain obscurations
and lowering visibilities at times under showers.  Skies will
become mostly clear by morning producing VFR conditions.
KMSO and KGPI will receive some east-northeast winds through the
evening hours before decreasing after 26/0300z. Otherwise VFR
conditions through Thanksgiving day.


.AIR STAGNATION...Moderate to strong inversions are expected under
mostly stable conditions through at least the middle of next week.
Cold pools that develop in the lower valleys may be hard to scour
out, producing air quality issues. Confidence for a long period of
inversions and poor mixing is low to moderate at this time.


MT...Winter Weather Advisory until 8 PM MST this evening
     Butte/Blackfoot Region.

ID...Winter Weather Advisory until 8 PM MST this evening Eastern
     Lemhi County.


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