Area Forecast Discussion
Issued by NWS Billings, MT

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990
FXUS65 KBYZ 161549
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
849 AM MST Thu Feb 16 2017

.UPDATE...

No update this morning for the inherited short term forecast. AAG

&&

.SHORT TERM...valid for Tdy and Fri...

Winds have hit advisory criteria many times tonight at Livingston
and Nye. Still experiencing surface pressure falls over south
central Canada. Gradient stays tight this morning, then backs off
some this afternoon. Guidance and local studies keeps winds at or
near advisory criteria this morning, then back it off this
afternoon. Will keep highlights in place. The rest of the western
and central plains will be breezy this morning, with winds
decreasing this afternoon.

Another mild day in store with persistent downslope flow.
Increased moisture aloft and weak cold advection aloft should keep
highs near yesterday levels, despite very warm start. A weak cold
front will push through the area tonight. This front does not
have a lot of punch with it as 850mb temperatures do not cool down
much. As an upper trough moves through the area tonight, ascent
will cause isolated to scattered showers to develop. Lack of cold
air will keep the precipitation as rain or a rain and snow mix.

Small scale ridge builds back in Friday as shortwave energy
continues to move northeast out of the area. Will linger low PoPs
over the east Friday morning as the wave exits into the Dakotas.
Cooler air will filter in, but still expecting above seasonal
highs with 850mb temperatures only falling to around 8c. TWH

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

For the weekend, strong southern portion of split Pacific trof
will be well to our south over northwestern Mexico, leaving a
couple of weaker shortwaves for our region. Potential for showers
exists in our west on Saturday, but stronger shortwave Sunday and
Sunday night may bring brief shower activity across our cwa.
Mountains should see a little snow here, but lower elevation temps
look to remain warm enough for just rain showers. Chance of pcpn
should exit to our east Monday morning.

Southwest flow aloft will favor our western mountains for snow
Monday and Tuesday as trof deepens off the Pacific coast. Tuesday
and Wednesday are when models begin to diverge more significantly.
The chance of pcpn will increase across lower elevations on these
days as heights fall with additional Pacific energy. The GFS is
strong enough with a Tuesday shortwave to allow for colder
Canadian air to change precipitation type over to snow by Tuesday
night into Wednesday, whereas the ECMWF is weaker and warmer in
this initial stage. Will stay with a compromise here but
confidence is relatively high in a general sense that we will
begin to see cooler temps and an increased chance of precipitation
by Wednesday. Mountains will see periods of snow throughout the
first half of next week.

As Pacific trof moves through the Rockies, we may be looking at a
lower elevation snow event in the Wednesday night to Thursday
Night or Friday time frame, with deep ascent and a shift to
easterly upslope winds, as 850mb temps fall well below zero. The
00z GFS and ECMWF are in overall agreement in this scenario at
this time, but obviously there remains a great deal of uncertainty
so far out in time. Something to watch in the models the next
couple days.

JKL


&&

.AVIATION...

SW winds will remain strong along the western foothills, with
gusts of 40-50 kts at KLVM decreasing to 30-40 kts tonight. Expect
VFR to prevail across the area today. A Pacific disturbance will
bring a few showers to lower elevations tonight, but with
continued VFR flight conditions. Mountains will be occasionally
obscured in snow showers tonight. JKL

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Fri     Sat     Sun     Mon     Tue     Wed
-------------------------------------------------------
BIL 058 037/056 031/050 036/055 034/054 040/057 032/045
    0/N 21/N    01/E    12/W    21/B    12/W    23/W
LVM 058 037/051 026/051 035/053 031/050 039/052 027/042
    0/N 22/W    02/W    13/W    22/W    33/W    24/W
HDN 058 034/056 027/049 029/055 028/053 031/054 028/045
    0/B 21/B    01/E    11/B    21/B    12/W    22/W
MLS 057 033/052 028/047 028/052 031/049 031/050 030/043
    0/B 12/J    00/B    01/B    22/W    12/W    22/W
4BQ 057 031/054 028/052 032/055 032/053 034/058 031/046
    0/U 02/J    00/B    00/B    22/W    11/B    22/W
BHK 056 033/050 026/046 030/053 032/049 031/052 031/042
    0/U 02/J    00/B    00/B    22/W    11/B    22/W
SHR 059 032/054 025/051 029/055 029/054 032/061 029/047
    0/U 21/B    10/B    00/B    21/U    12/W    22/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Wind Advisory in effect until 9 PM MST this evening FOR ZONES
      65-66.
WY...None.

&&

$$
weather.gov/billings



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