Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 131027

Area Forecast Discussion
National Weather Service Billings MT
327 AM MST Tue Feb 13 2018

.SHORT TERM...valid for Tdy and Wed...

Relatively busy short term period ahead, with strong and gusty
gap winds tonight and a disturbance crosses the region Wednesday
evening/night. A short period of quiet weather is expected across region
today, with a warming trend through Wednesday afternoon.

The period begins very cold this morning, with widespread sub-
zero temperatures. Shortwave ridging building in this morning will
bringing warmer and quiet conditions for the day. Downslope flow
develops under the ridge, and will help scour out the coldest air.
Expect to see high temps in the mid to upper 30s across west and
central zones. Cold air is a bit more stubborn in the east, so
areas east of Forsyth can expect cooler temps in the upper 20s and
near 30 in these areas.

A disturbance working into northeast CONUS flattens the ridge
fairly quickly late this afternoon, and strong lee troffing
develops quickly this evening along our mountain foothills and
quickly increase the winds overnight. Favored gap wind locations
like Livingston, and Nye, should see 60 to 70 mph winds overnight
tonight. Strong winds are also possible from Big Timber north to
Harlowton where gusts around 55 mph are possible.

The disturbance will begin to impact northwestern and western zones
by Wednesday evening, with cold front dropping quickly south
through the evening. This system entering the region with cut off
the winds, but will bring increasing rain and snow showers across
the area. Most recent indications are for precip to start as rain
or a rain/snow mix and then turn to snow overnight Wednesday
behind the front. Any rain that does fall will cause issues, with
potential to be freezing rain, or result in flash-freezing as
cold air enters the region.

Snow showers will continue into Thursday morning as another round
of colder temperatures moves in. Currently expect around 2 to 4
inches of snow with this next system so another round of travel
difficulties is anticipated. AAG

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

Upper trof/cyclonic flow continue from the short term (see
discussion above) into Thursday. We increased PoP`s for Thursday
morning, trending them down into the latter part of the day.
Thursday morning commute will likely see travel impacts with
accumulating snowfall and reduced visibility. Trof axis slides
southeast past our CWA by Thursday night. However, another weak
shortwave in the northwest flow aloft tracks over southwestern/south
central Montana Friday. This may bring a shot of snow to the
mountains with a little action over the plains as well.
Accumulations should be relatively light with this trailing short
wave system.

A series of short waves then begins to track into the Rockies
into the weekend which is looking to be a rather unsettled period.
Mild temps Saturday will likely give way to colder temps for
Sunday as another surge of cold air invades Saturday night. There
appears to be a good chance of more accumulating snow Saturday
night into Sunday.

Models agree that cyclonic flow and unsettled conditions will
prevail into next week as well. The degree and strength of the
systems is still in question due to inconsistencies in the
various models. We have opted to weight toward cooler and
relatively wet solutions for now. BT



Expect mostly clear skies and VFR to prevail today. Main threat
to aviation interests will be gusty winds around 25-35kts across
KLVM, K6SO and nearby foothills. KBIL will also experience
15-30kts gusts at times. Even stronger gusts up to 60kts are
expected at KLVM from 7 PM this evening into Wednesday morning.
Some LLWS is possible over SE MT after 12z Tue as well. BT



    Tdy Wed     Thu     Fri     Sat     Sun     Mon
BIL 034 026/040 009/017 004/034 022/041 017/025 004/021
    0/U 02/O    67/S    02/S    22/O    54/S    33/S
LVM 038 028/040 014/023 011/036 026/041 021/030 009/025
    0/N 05/O    67/S    03/S    22/O    54/S    43/S
HDN 035 016/042 009/017 902/033 018/038 012/023 002/018
    0/U 02/R    66/S    02/S    22/S    54/S    33/S
MLS 026 016/039 005/012 904/028 015/034 011/017 906/011
    0/U 02/O    55/S    01/B    13/S    43/S    33/S
4BQ 030 015/041 010/017 903/032 017/038 014/024 000/017
    0/U 01/B    65/S    01/B    12/S    33/S    23/S
BHK 030 016/040 005/012 904/028 013/035 012/019 905/011
    0/U 01/N    64/S    01/B    12/S    33/S    34/S
SHR 038 018/044 012/019 902/033 016/040 017/025 001/019
    0/U 02/R    76/S    01/B    11/B    56/S    43/S


MT...Wind Advisory in effect from 6 PM this evening to noon MST
      Wednesday FOR ZONES 65-66.


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