Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 210903

Area Forecast Discussion
National Weather Service Billings MT
303 AM MDT Sat Apr 21 2018

.SHORT TERM...valid for Tdy and Sun...

We are looking at a beautiful spring day to start the weekend with
mostly sunny skies common. Thanks to some prefrontal warming with
soundings showing mixing above 600mb, look for highs in the 60s
to lower 70s across the CWA. However, a weather system moving
across Canada will drag a cold front across our region this
evening. There are some decent pressure rises progged behind the
front (~9 mb/6 hrs) which may produce some brisk post frontal w/nw
winds for a couple of hours. Otherwise, there is little if any
upper forcing support and little moisture available. So overall,
this looks like a dry frontal passage. We will continue to carry
low PoP`s along the Beartooths/Pryors/BigHorns and nearby

Easterly winds and some cloud cover Sunday will mean cooler
afternoon highs, but still seasonal in the upper 50s to lower 60s.
However, look for increasing cloud cover and scattered rain and
high elevations snow showers developing late in the day as a
trough moves into the inner northern Rockies. This system will
track right over our CWA late Sunday night spreading
precipitation from west to east overnight. Several inches of wet
snow are possible in the high country with some accumulation also
possible in the foothills by Monday morning. The system will lead
to a very wet and cool Monday (see discussion below). BT

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

Long term begins Monday morning with a cold wet rain prevailing
across the forecast area in the lower elevations and a heavy wet
snow in the mountains. The big question mark will be along the
foothills and higher hills from Livingston to Nye to Red Lodge.
Likely will see a rain/snow mix in the morning that transitions to
rain in the afternoon. Snow levels will remain steady, or
slightly rise through the afternoon until levels drop again
overnight into Tuesday. Most of the accumulations will be on
grassy surfaces with this system, but can`t rule out some slushy
roads in the morning and again Monday night in any heavier showers
were snow is dominant. Other concerns with this system involve
risks to young livestock as conditions will be cold and wet
through the day. The storm system begins to push east out of the
region by Monday evening, and folks east of Billings and Sheridan
could see snow accumulations overnight into early Tuesday
morning before things clear up later in the morning. Cooler
temperatures and further dynamic cooling overnight could allow
cold enough conditions for snow accumulations, but accumulations
look light at this time.

Warmer and drier conditions anticipated Tuesday into Wednesday as
a small ridge of high pressure, and southwest flow, moves in.
Conditions will be short lived as a clipper system drops in
quickly from the north Wednesday night into Thursday bringing
another chance for rain showers (mostly west of Miles-
City/Broadus). Northerly flow on Thursday behind the clipper will
keep things slighty cooler but expect another warm up into the
weekend as a ridge of high pressure moves back in from the west.


VFR conditions expected through the TAF period. Winds will shift
to the southwest through the day but will remain relatively light
except for KLVM where 25 knot gusts possible in the afternoon.


    Tdy Sun     Mon     Tue     Wed     Thu     Fri
BIL 071 041/061 037/046 030/058 035/066 036/062 038/069
    0/U 10/B    49/W    20/U    01/U    21/U    00/U
LVM 069 036/062 035/042 025/057 031/063 033/062 035/066
    0/U 11/B    88/W    10/U    01/U    21/U    11/U
HDN 072 040/063 036/046 029/057 032/065 035/061 036/069
    0/U 10/B    39/W    20/U    01/U    21/U    10/U
MLS 070 039/062 037/047 030/058 035/064 035/060 036/066
    0/U 00/B    47/W    30/B    00/U    11/U    00/U
4BQ 065 038/061 038/048 031/055 034/064 034/057 036/064
    0/U 00/B    28/W    60/B    00/U    11/U    00/U
BHK 063 038/059 037/044 030/053 032/061 036/055 036/062
    0/U 00/B    17/W    51/B    00/U    11/U    00/U
SHR 067 036/064 035/044 028/056 030/065 033/058 035/067
    0/U 00/U    27/W    51/B    01/U    21/U    10/U




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