Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 222122
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
222 PM MST Wed Feb 22 2017

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

Increased snow accumulations with next system due to a more
northerly track. Storm system will impact the area with periods
of snow over the next 72 hours, heaviest along and west of a
Roundup to Broadus line and specifically in the north and east
facing foothills. Issued Winter Storm Warnings for western
mountains and favored foothills locations, with Winter Weather
Advisories for surrounding areas. At this point SE MT looks to see
only a couple of inches of snow so left those areas out of
highlites for now but if system trends any further north will need
something for at least Powder River and Carter counties.

Broad west coast trof coming together this afternoon as energy
drops south from western Canada and fuses with energy out of
California. Plenty of energy and moisture out ahead of the upper
low which is producing rain/snow showers across much of the
forecast area this afternoon. Have picked up nearly a tenth of an
inch precipitation in the Billings area so far today from this
activity. Surface cold front is slowly moving through western
zones heading into the foothills this afternoon, after clearing
the eastern portion of the forecast area this morning. Additional
colder air will filter in tonight as the cold front builds into
the foothills and deepens up. This will transition precipitation
from convective in nature to more stratiform overnight, with
precipitation turning over to all snow late evening. Jet energy
will develop over the area early tomorrow morning and persist
through the day Thursday providing the dynamics for the heaviest
snowfall to develop. Core of upper system will slide across
Southern/Central Wyoming Thursday afternoon into the overnight
hours providing additional snow enhancement over southern zones.
Low moves into the Dakotas on Friday which should taper snow rates
down and bring an end to significant impacts so ended highlites
mid day Friday.

Temperatures never get terribly cold with this system with highs
Thursday and Friday in the 25 to 35 degree range and lows in the
15 to 25 range. This sets up a scenario where a good amount of
melting is possible during the daylight hours so accumulations in
some areas may be overdone a bit. Lowered snow ratios a good deal
during the afternoon hours to account for this. Metro model
simulations show afternoon road temperatures in the lower
elevations pushing into the 40s, so roads that get snow covered
and slick during the night may melt out during the day or become
generally slushy. Foothill and mountain roads will be snow packed.

Snow amounts...Latest model and WPC consensus shows western
mountains in the 10 to 16 inch range, Bighorn mountains in the 8
to 12 inch range. The Beartooth/Red Lodge foothills can expect 6
to 12 inches with 5 to 10 in the Sheridan foothills. Central zones
will see 3 to 6 inches trending toward 6 to 10 inches further
west into the Big Timber and Livingston areas. This snow is going
to be more of the wet variety so folks will need to take it easy
shoveling, though melting on concrete/asphalt surfaces during the
day will help. Chambers

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

Little in the way of changes for the extended forecast period.
Overall, expect a progressive and unsettled pattern, with below
normal temperatures through the period.

Weak energy will cross the region Saturday, with continued
showers expected. A stronger wave crosses the area Saturday
night/Sunday morning, and should spread more widespread showers
across the region. The system is pretty quick...so do not expect
significant snow accumulations at this time. Shortwave ridging
will build over the region by Sunday afternoon. A Pacific trof
pushes into the pacific northwest by Sunday night and digs south,
flattening the flow across the CWA. Trof remains open and pushes
east through Tuesday. Models vary greatly on how they handle the
system crossing the region, but generally appear to bring pieces
of energy and pacific moisture through the region through Tuesday
night. Expect to see some brief clearing for Wednesday as flow
aloft turns northwest behind the trof, before the next system
approaches Thursday. AAG

&&

.AVIATION...

Cold Front is through the region this afternoon, with winds now
ranging from Northeast to Northwest to Northeast across the
region. Rain and snow showers are impacting a large portion of the
CWA at this time in unstable atmosphere. Rain, snow, or rain/snow
mix have been locally heavy, with IFR/LIFR conditions, and quick
accumulations of snow in some areas. Showers will continue through
the day. More widespread snow is expected tonight through Friday,
with IFR to LIFR CIGS and VIS possible in heavier snow throughout
the period. AAG

&&

.PRELIMINARY POINT TEMP/POPS...

    Thu     Fri     Sat     Sun     Mon     Tue     Wed
-----------------------------------------------------------
BIL 027/033 021/033 016/032 015/033 015/033 018/031 020/038
    68/S    65/S    32/J    21/B    22/J    32/J    22/J
LVM 020/029 013/028 011/027 009/029 012/032 014/031 017/034
    98/S    76/S    42/J    21/N    33/J    32/J    22/J
HDN 025/036 019/035 015/033 014/034 013/033 016/032 017/039
    68/S    64/S    22/J    21/B    12/J    33/J    12/J
MLS 027/038 022/036 019/035 020/036 018/035 020/033 020/040
    33/S    22/S    22/J    21/B    22/J    33/J    11/N
4BQ 025/037 019/035 016/035 018/035 015/037 020/033 017/038
    46/S    43/S    12/J    21/B    01/B    34/J    11/N
BHK 023/033 018/032 016/031 017/033 015/034 017/029 016/035
    32/S    21/E    22/J    21/B    11/B    34/J    11/B
SHR 023/031 014/029 009/030 008/029 008/031 012/030 014/035
    69/S    75/S    31/E    11/B    12/J    34/J    22/J

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory in effect from midnight tonight to
      noon MST Friday FOR ZONES 28-29-34-35-39-40-42-57-58-63-64.
     Winter Storm Warning in effect from midnight tonight to noon
      MST Friday FOR ZONES 38-41-56-65>68.
WY...Winter Weather Advisory in effect from midnight tonight to
      noon MST Friday FOR ZONE 98.
     Winter Storm Warning in effect from midnight tonight to noon
      MST Friday FOR ZONE 99.

&&

$$
weather.gov/billings



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