Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 101102
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
402 AM MST Sat Dec 10 2016

.SHORT TERM...valid for Tdy and Sun...

Active weather pattern will continue across the forecast area
today into this evening. A strong jet stream will continue to move
onshore across the Pacific northwest and move eastward across the
northern Rockies today before shifting south of the forecast area
on Sunday. This will bring numerous periods of snow into Monday
across the Crazy and Beartooth/Absaroka Mountains. For the lower
elevations, light snowfall continues across all areas with the
exception of far southeast Montana and the Red Lodge foothills
areas. The foothill areas are experiencing some downsloping early
this morning so we are not expecting much if any snow through this
morning. The remaining areas will see accumulations around an
inch.

There may be a brief break in the snow later this morning into
early this afternoon but we are expecting another round of light
snow by late afternoon into this evening. As a result, we will
continue with the current winter weather advisories. An additional
inch or two of snow will be possible with this next wave later
this afternoon into this evening. Models try to scour out the
arctic air along and west of a Billings to Sheridan line today
where temperatures may reach the 20s to lower 30s, but single
digits and teens will continue east of this line.

Sunday, for the most part will see a break in the action. This
will also be the warmest day for the next week as most areas will
climb into the upper 20s to lower 30s with the exception of some
teens out along the Dakota borders. Another arctic front will
blast through the forecast area late Sunday night into Monday
morning bringing a return to very cold temperatures, as well as
another round of snow. Hooley

.LONG TERM...valid for Mon...Tue...Wed...Thu...Fri...

Next arctic front will surge into the cwa early Monday, bringing
sharply colder temps than Sunday and a period of snowfall. Pacific
overrunning moisture will linger into Monday night, and this still
appears to be a fairly typical 1-3 inch arctic fropa snowfall,
with snow becoming lighter through the day Monday as temps turn
too cold for dendritic growth. Pcpn should taper off from north
to south late Monday night into Tuesday as we pull in drier air
from the northwest, but there are some model differences in
timing.

Temps will remain well below normal through midweek, and models
still agree in a period of mostly dry wx into Wednesday as NW
flow aloft suppresses the Pacific moisture plume and baroclinicity
to our south. Will keep low pops for our southern mountains only.
Given we will have widespread snow cover, a couple mostly clear
nights could be quite chilly both Tuesday and Wednesday nights.

Models continue to have a difficult time handling the phasing of a
Canadian clipper and Pacific trof by Thursday and Friday. This is
a very interesting period of weather as there is potential for
both another snow event and even colder arctic air. Must stress
the uncertainty in details here, but will keep broadbrushed pops
for Thursday and Friday. Confidence is actually growing for
another arctic frontal passage by Friday, with the EC and GFS each
suggesting high temps near or perhaps even below zero as we tap
into an airmass from the Canadian arctic.

JKL

&&

.AVIATION...

Periodic snow will impact the region today and tonight. VFR will
be the most dominant flight condition across the lower elevations,
but there will be areas of MVFR/IFR, and mountains will be mostly
obscured. Snowfall will shift to the southern mountains and
foothills by this evening, then taper off late tonight. JKL


&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Sun     Mon     Tue     Wed     Thu     Fri
-------------------------------------------------------
BIL 022 014/030 008/009 901/011 903/013 901/012 904/000
    8/S 31/B    36/S    62/J    01/U    12/S    33/S
LVM 033 015/031 016/018 001/014 902/014 002/015 902/001
    8/S 42/S    36/S    62/J    11/U    12/S    44/S
HDN 023 009/030 007/010 903/013 907/014 905/013 905/002
    8/S 41/B    36/S    52/J    11/U    11/B    33/S
MLS 013 000/020 001/004 905/011 905/012 905/011 906/001
    4/S 61/B    35/S    21/B    00/U    01/B    23/S
4BQ 020 006/027 005/010 904/012 903/013 903/013 903/004
    4/S 41/B    25/S    31/B    00/U    11/B    23/S
BHK 009 902/017 901/003 907/007 906/006 907/006 907/000
    4/S 61/B    24/S    21/B    00/B    01/B    23/S
SHR 028 012/031 011/015 903/010 906/013 000/014 905/001
    4/S 61/B    26/S    52/J    11/U    12/S    33/S

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory in effect until noon MST today FOR
      ZONES 28-29-34-35-39>42-56-63>66.
     Winter Storm Warning in effect until 6 PM MST this evening
      FOR ZONE 67.
WY...Winter Weather Advisory in effect until 6 PM MST this evening
      FOR ZONE 98.

&&

$$
weather.gov/billings


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