Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 240355
AFDBYZ

Area Forecast Discussion...Updated
National Weather Service Billings MT
855 PM MST Thu Feb 23 2017

.UPDATE...
Current forecast on track with no updates. Light snow across the
region with upslope and weak instability the main features. Colder
cloud tops remaining in Wyoming and with dynamics generally
tracking away from the area tonight do not expect much more
intensification. Favored areas will continue to be along the Red
Lodge Foothills and the Pryor and Big Horn Mountains where current
winter weather advisories are in effect. borsum

&&

.SHORT TERM...valid for Fri and Sat...

Upper level storm system continues to shift across Wyoming, but is
doing so in pieces. Water Vapor imagery shows a broad deformation
band to the north of the main circulations stretching from Boise
ID across southern MT and over much of South Dakota at 2pm. The
elongated piecemeal composition of this system is making it
difficult to pinpoint forcing mechanisms and models continue to
struggle with precipitation placement outside of areas very close
to the center of the low track. For most of the day snow has ended
just south of Sheridan, while areas around Piney Creek and Buffalo
have seen visibility under a mile in snow, and this despite
favorable upslope flow out of the east all day. Upslope snow has
continued in western foothills all day, but as the upper system
shifts further east snow rates will trend downward. So have
cancelled all the Winter Storm Warnings for our area. Downgraded
the Beartooth and Bighorn mountain foothills to an advisory and
dropped the warning for the mountains. Biggest concern with
additional snowfall this afternoon into tonight will not be the
amounts, but the melting and refreezing on roads that could make
travel treacherous in some areas. Models continue to advertise an
uptick in snow shower activity over the next several hours lasting
through late tonight and radar has filled in with more areas of
light snow so that seems on track. Kept precipitation chances
high and adjusted accumulations downward overnight into tomorrow
in most locations, reflecting the main concern being icy roads as
opposed to heavy snow.

Rockies storm system pushes well to the east tomorrow but leaves
weak upslope flow and some moderate mid level instability in
place for continued chance of snow showers into the evening. A
clipper wave drops in from the northwest late Friday night
enhancing shower chances going into Saturday. Once that clears
will see a drying trend for the end of the weekend. Not seeing
much if any snow accumulation with this activity right now across
the lower elevations. Temperatures will stay in the 25 to 35 range
for highs Friday and Saturday. Chambers

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

Little changes made to the extended portion of the forecast
period. General cyclonic flow aloft over the region point to
progressive and unsettled pattern for the extended period.
Temperatures will remain well below seasonal average through the
period, but will slowly trend warmer to end the period.

A shortwave ridge is in control over the region to start the day
Sunday...but is quickly flattened as an upper level trof drops
southward. This trof is situated and moves such that it keeps snow
showers across the region from Sunday evening/night through
Tuesday night. Shallow shortwave ridging will cross the region
Wednesday. Ridging is quickly washed out by Wednesday evening as
another reinforcing shortwave drops into the area, bringing another
chance of snow showers for Thursday. Unsettled northwest flow will
persist thereafter. AAG
&&

.AVIATION...


MVFR conditions prevail under low CIGS across much of the region
and will persist through the night. Snow showers are expected
across much of the area overnight. Locally heavy snow showers will
lower VIS to IFR/LIFR at times. AAG/STP


&&

.PRELIMINARY POINT TEMP/POPS...

    Fri     Sat     Sun     Mon     Tue     Wed     Thu
-----------------------------------------------------------
BIL 022/032 018/032 017/035 017/033 018/032 018/039 024/043
    64/J    34/J    21/B    32/J    22/J    21/B    22/W
LVM 015/027 012/026 013/029 012/030 014/028 014/034 021/040
    85/J    54/J    22/J    44/J    43/J    22/J    33/W
HDN 023/034 018/034 017/036 016/035 018/033 016/040 021/043
    53/J    33/J    21/B    22/J    22/J    21/B    22/W
MLS 021/036 019/034 019/038 019/035 020/034 018/039 022/041
    31/E    23/J    21/B    22/J    22/J    21/B    12/W
4BQ 020/034 018/034 017/037 016/037 019/035 017/038 020/042
    41/E    24/J    21/B    22/J    22/J    21/B    22/W
BHK 017/032 016/031 017/035 015/032 017/030 015/034 019/037
    31/B    23/J    21/B    22/J    22/J    21/B    12/W
SHR 017/029 013/030 011/031 010/031 014/030 013/036 016/041
    83/J    34/J    31/B    11/B    22/J    21/B    22/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory in effect until noon MST Friday FOR
      ZONES 38-41-56-65-66.
WY...Winter Weather Advisory in effect until noon MST Friday FOR
      ZONES 98-99.

&&

$$
weather.gov/billings



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