Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 120345

Area Forecast Discussion
National Weather Service Billings MT
845 PM MST Wed Jan 11 2017


Made several minor changes this evening to the short term
forecast. Main changes centered around lowering overnight lows
across the northern tier of the CWA. Temps are dropping very
quickly as mid level clouds clear...approaching inherited
forecast lows in some areas.

Also increased winds slightly for the next few hours across much
of the area. This should limit cool off some. Winds do look like
they should drop off after midnight...and with mainly clear
skies...should allow temps to drop quickly through the early
morning hours Thursday.

Otherwise the inherited forecast appears to be in good shape. AAG


.SHORT TERM...valid for Thu and Fri...

Flow aloft veering this afternoon and evening to more
northwesterly as a fast moving potent upper low moves from
Saskatchewan southeastward into southern Manitoba tonight. This
will bring a drying of the airmass for northern parts of the area
but southern areas still under the influence of a more westerly
flow with moisture being pushed into southwest Montana and
northern Wyoming from a weaker low over Oregon. As the Canadian
low shifts eastward on Thursday moisture tap begins to dry out
but the Oregon low ejects across the region as a weakening
shortwave. Friday a splitting flow over the Pacific northwest
keeps a west northwesterly flow aloft but the airmass will be

At the surface upslope gradients continue along the foothills and
over Sheridan County but radar indicates snowfall has decreased.
Will allow the winter weather advisories to expire but winter
storm warning for the mountains will continue and satellite shows
cooling cloud tops over southeast Idaho heading into that area.
Later tonight a clipper system moving into the Dakotas brings a
reinforcing cold push into southeast Montana with enough wind to
push wind chills below 20 below zero tonight. Will issue a wind
chill advisory for southeast Montana for tonight. For Thursday
looks like a another cold day with Billings area seeing some of
the colder temperatures due to drainage from the Big Horn basin.

Thursday night a leeside trough begins to develop along the
foothills but core of the high pressure remains over western
Montana as opposed to northwest Wyoming and southeast Idaho. This
will bring increasing winds over the western zones overnight
though should not favor particularly strong gap flow winds. Should
be enough wind across the western zones to combine with recent
snowfall which is pretty fluffy to begin causing areas of blowing
snow even though speeds may not go much above 20 mph. This will
continue into Friday. Temperatures will warm for Friday due to a
warmer start but do not expect moderation above freezing. Big
Horn basin will continue to influence Billings temperatures due to
cold air drainage keeping highs a few degrees cooler. borsum

.LONG TERM...valid for Sat...Sun...Mon...Tue...Wed...

Dry weather can be expected Saturday into Tuesday as high pressure
builds over the Northern Rockies and a low over the Four Corners
region puts the area under split flow aloft. At the surface,
pressure gradients will align themselves to produce some gusty
winds across western and central areas on Saturday, so blowing
snow remains a concern. Models prog surface pressure gradients to
tighten again Monday into Tuesday increasing winds across the
western foothills. A shortwave sliding across the region along
with Pacific moisture pushing in from the west will bring the
next shot of precipitation to the southwest mountains, and
potentially the plains Tuesday night into Wednesday.

High temperatures are expected to be in the 20s on Saturday,
potentially moderating up into the 30s by the early to the middle
part of next week. Uncertainty exists in the temperatures for
central areas as cold air draining out of the Big Horn Basin
would keep temperatures cooler. STP



Light snow and local MVFR conditions will continue to taper off
over southern mountain and foothills zones this evening with
mostly clear conditions overnight. The exception will be over the
southern Beartooth/Absaroka mountains where mountain obscuration
and periods of snow will persist into tomorrow. Chambers


    Thu     Fri     Sat     Sun     Mon     Tue     Wed
BIL 904/010 002/021 009/025 015/030 014/032 020/036 024/038
    21/B    00/Q    00/U    00/N    00/N    01/N    11/B
LVM 901/025 007/027 009/030 014/034 013/037 021/039 026/043
    31/B    00/Q    00/Q    00/N    00/N    01/N    12/W
HDN 913/014 903/021 902/023 005/028 006/029 010/032 015/037
    20/B    00/U    00/U    00/U    00/U    01/U    11/B
MLS 917/005 906/018 902/021 007/027 006/029 014/033 019/037
    00/U    00/U    00/U    00/U    00/U    00/U    11/B
4BQ 912/010 000/020 901/022 006/028 006/029 012/033 016/036
    30/U    00/U    00/U    00/U    00/U    00/U    11/B
BHK 912/004 908/019 000/021 007/026 007/028 013/032 019/036
    00/U    00/U    00/U    00/U    00/U    00/U    11/B
SHR 906/018 000/027 001/032 004/033 007/034 012/038 016/042
    31/B    00/U    00/U    00/U    00/U    00/U    11/B


MT...Wind Chill Advisory in effect until 11 AM MST Thursday FOR
      ZONES 31>33-36-37.
     Winter Storm Warning in effect until 6 AM MST Thursday FOR
      ZONE 67.


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