Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 051034

Area Forecast Discussion
National Weather Service Billings MT
334 AM MST Mon Dec 5 2016

.SHORT TERM...valid for Tdy and Tue...

Initial cold front pushed through the area overnight. As the
front pushed through, patches of rain/snow and mixed precip
pushed from the Bull Mountains down to Sheridan, however most of
that precip missed the Billings area.

Currently, snow is ongoing from Livingston through Red Lodge and
into northern Bighorn County along the remainder of the front
axis caught on the elevated terrain. Light snow should continue
along this area through the early morning hours.

Hi-res models indicate a drier solution for Billings and areas
west today, while areas from Forsyth to Baker have trended more
wet. Axis of coldest air remains a little more east than
previously forecast through the day today. Along the leading edge
of the arctic air, a band of snow from Forsyth to Baker will sag
southward through the day, with accumulations generally 1 to 2
inches. Billings and valleys furthers west will keep a slight
chance of seeing some snow showers but accumulations should
generally be an inch or less.

Arctic intrusion is a little slower than previously forecast. For
this reason nudged temps up a few degrees through Tuesday. Walsh

.LONG TERM...valid for Wed...Thu...Fri...Sat...Sun...

Main change to the extended was to linger the cold air longer.
Models have slowed the push east of the arctic another day and
have therefore lowered highs quite a bit for Thursday and Friday.
There is the idea that the arctic air will try to retreat on
Thursday but even now the latest models were backing off on that
somewhat. A lot of energy was set to pour into the northwest
United States and this keeps lower pressure over the Great Basin
which would aid in keeping easterly low level winds over southern
Montana into Saturday. Low level downslope flow does not push
across in earnest until Saturday night and early Sunday and this
should keep temperatures below seasonal through the extended.

Wind chill could become a concern for Wednesday into Thursday
with low level northwest winds of 5-15 mph. Temperatures will
certainly be cold enough but surface pressure gradient may not be
quite tight enough in eastern Montana to push winds speeds above
the 10mph threshold for bitterly cold wind chills. Will continue
to monitor this situation closely. Models brings the next over
running system in Thursday night into Saturday. There is not a
consensus on timing for this, but models seem to be hitting the
western and southern zones hardest for the potential for snowfall.
Kept PoPs at inherited levels for Thursday through Saturday but
may need to be bumped in time as the event approaches and if
models unite on a solution. TWH


Snow showers will continue south of a KLVM to KBIL to KMLS line
this morning. Flight conditions will lower to IFR and LIFR in the
heavier showers. The snow showers will taper off and slide south
as the morning progresses. Additional snow showers are expected to
develop late this morning and early this afternoon. The most
likely location for these snow showers will be east of a KBIL to
KSHR line. The snow showers could be locally heavy and drop
conditions to IFR to LIFR. TWH


    Tdy Tue     Wed     Thu     Fri     Sat     Sun
BIL 027 007/010 905/004 905/007 007/026 018/029 019/034
    4/J 32/J    21/E    11/U    12/J    32/J    21/B
LVM 022 001/010 910/005 906/010 010/035 023/035 024/035
    4/J 22/J    21/B    11/B    23/J    42/J    22/J
HDN 028 006/011 906/003 908/009 005/023 013/030 014/034
    4/J 32/J    11/E    00/U    12/J    32/J    21/B
MLS 026 004/010 905/003 910/004 904/015 004/017 006/026
    5/J 11/B    11/E    00/B    01/E    32/J    21/B
4BQ 026 003/010 907/003 914/007 901/020 009/029 006/029
    5/J 11/B    11/E    00/U    01/E    32/J    21/B
BHK 024 003/007 906/002 913/004 907/011 000/016 002/024
    6/J 31/E    11/E    00/B    01/B    22/J    21/B
SHR 026 003/013 907/007 910/013 005/032 016/031 014/032
    7/J 21/B    21/B    00/U    11/B    43/J    21/B


MT...Winter Weather Advisory in effect until 6 PM MST this evening
      FOR ZONES 34-36>41-56>58-64>66.
     Winter Storm Warning in effect until noon MST today FOR ZONE
WY...Winter Weather Advisory in effect until 6 PM MST this evening
      FOR ZONES 98-99.


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