Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 061655
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
955 AM MST Wed Dec 6 2017

.UPDATE...

Strong cold was passing through eastern Montana this morning from
the north. As of 10 am this front was oriented from Jordan southeast
through Miles City and to Alzada. As the clipper slides south
through the rest of this morning these snow showers will slowly
slide south along the front. Steep lapse rates along the front,
along with modest converging flow along the front will help drive
snow showers through the morning and early afternoon. Conditions
will gradually improve behind the front but expect very chilly
temperatures in the low to mid teens this afternoon. Made no
changes to the winter weather advisory in eastern Montana. While
the snow has stopped behind the front, breezy conditions today
will cause some patchy areas of blowing snow.

The strongest winds for today are likely over, but folks east of
the Big Horns and in eastern Montana could still see 40 to 50 mph
wind gusts through the remainder of the day before the strong
mid-level winds move southeast into the Dakotas and central
Wyoming.

Elsewhere the forecast still looks on track and only made minor
changes to the precip chances for tonight as a weak disturbance
slides through...bringing another round of light mountain snow for
a few hours. Dobbs

&&

.SHORT TERM...valid for Tdy and Thu...

Some lingering energy behind the clipper system from yesterday
continues to move through eastern Montana. This energy is slowly
dropping to the south and east, but the light snow across eastern
Montana and down into Sheridan will continue through much of the
morning and afternoon. As a ridge of high pressure across the
western United States continues to build, the pressure gradient
across the area will remain fairly tight. This is going to keep
conditions breezy today. Winds are not expected to be as strong as
they were yesterday as winds aloft are weaker so there is not as
much momentum to mix down. However, gusts into the 40s are
possible through the afternoon. With the gusty winds and falling
snow combine with the snow over the past couple of day producing
some blowing and drifting snow, will keep the Winter Weather
Advisory going. Temperatures will still remain around seasonal
averages to a little below in eastern Montana with the light snow.

Tomorrow will be drier and warmer across the area. Winds will
still be breezy but a little lighter than today. However, as
another wave of energy comes across the pressure gradient will
tighten tomorrow afternoon. This will be dry pulse of energy, but
it will result in winds increasing in the afternoon and evening.
Reimer

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

Models agree that a powerful upper ridge situated over the western
coastal states will be the primary influence over our region
to start our extended period (Friday). The models do indicate a
clipper system zipping through NE Montana late Sunday/Sunday
night. GFS is much more aggressive with this system while the
ECMWF keeps any dynamics and precipitation over the Dakotas. The
GFS leaves a hint of cyclonic flow along the Dakota border
counties through Tuesday morning, but the ECMWF keeps a dry
anti-cyclonic flow the dominant pattern. Given the range of spread
it seems prudent we add at least have some slight chance PoP`s in
our east late Sunday. Further out than that, the ECMWF hints at
the ridge breaking down at the middle part of next week, but
confidence is not very high with regard to this. Thus, other than
adding some slight chance PoP`s early next week in the east we
will opt to keep other changes to a minimum. BT

&&

.AVIATION...

Areas of snow and blowing snow will continue east of KBIL today,
impacting KMLS/KBHK and possibly KSHR with flight conditions
periodically down to MVFR/IFR. NW winds will gust to 25-40 kts.
VFR conditions will prevail further west. Snow will end and VFR
will prevail across the region tonight and Thursday morning, with
some light snow showers possible over the mountains. JKL

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Thu     Fri     Sat     Sun     Mon     Tue
-------------------------------------------------------
BIL 035 027/044 034/054 032/051 031/050 030/047 033/052
    1/N 11/N    00/B    00/U    00/B    11/B    11/B
LVM 032 026/040 029/049 027/047 026/046 026/044 028/047
    0/N 11/N    00/N    00/U    00/B    10/B    11/B
HDN 034 024/043 028/052 026/051 026/050 026/047 028/052
    2/J 11/B    00/B    00/U    00/U    21/B    11/B
MLS 030 020/042 028/047 025/048 025/046 025/042 025/046
    6/J 11/B    00/B    00/U    00/U    21/B    11/B
4BQ 029 018/038 029/046 027/050 026/049 026/044 025/047
    6/J 21/N    00/B    00/U    00/U    21/B    11/B
BHK 017 012/034 024/041 020/045 023/043 022/038 020/041
    8/J 11/E    00/B    00/U    00/U    21/B    11/B
SHR 032 022/041 029/052 028/053 023/052 024/047 025/054
    3/J 11/N    00/B    00/U    00/U    22/O    11/B

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory in effect until 6 PM MST this evening
      FOR ZONES 33-37.
WY...None.

&&

$$
weather.gov/billings


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