Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 270542

Area Forecast Discussion
National Weather Service Cheyenne WY
1142 PM MDT Wed Apr 26 2017

.SHORT TERM...(This evening through Thursday)
Issued at 327 PM MDT Wed Apr 26 2017

For the afternoon forecast package we keep the Winter Weather
Advisory going tonight through Thursday for the Sierra Madre and
Snowy Ranges as snow showers become more widespread and where 8
to 12 inches of new snow is expected through early Thursday
evening ahead of the approaching series of shortwaves coming down
a rather active northwesterly flow aloft. Main concern for
tomorrow could be gusts 30 to 40 mph on higher elevations that
could restrict visibility. For tonight we expect mostly rain below
6000 ft elevation with a mix of rain and snow early this evening
6000-7000 ft changing over to snow showers overnight..with mostly
a mix of rain/snow showers farther east of I-25. The models
continue to want to start closing off an upper low either in
Colorado or over southern Wyoming late the active
pattern continues through Thursday with 700 mb temperatures
starting to drop off precipitously Thursday night as the main
upper system starts to swing through and the low starts to close

.LONG TERM...(Thursday night through Wednesday)
Issued at 327 PM MDT Wed Apr 26 2017

Cool and wet conditions will continue over the CWA Friday as an
upper low develops over the Wy/Co area with most upslope flow also
present as a cool surface high settles south out of Canada. Decent
snowfall a possibility over the mtns and possible the adjacent
high plains into Friday night. The upper low will drop southward
to the 4 corners area Friday night then turn east Saturday...
reaching the southern plains early Sunday. This pulls most of the
pcpn south of the CWA by late in the day Saturday and trended the
pops in that direction. Remaining on the cool side Saturday under
rather cold mid-level temperatures. Warming again Sunday with
mainly dry weather as a short upper ridge moves across the region.
Monday through Wednesday looking somewhat cool and unsettled as
northwesterly upper flow will be over the area with several
impulses dropping southeast across the region bringing rain and
snow showers. Temperatures should be below seasonal averages in
this pattern.


.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1136 PM MDT Wed Apr 26 2017

VFR prevails initially across the area with just a few scattered
showers near KSNY. As winds become more SE`ly tonight ahead of an
approaching front, increasing low level warm advection will lower
ceilings to MVFR for most NE terminals. Upslope along the
Cheyenne Ridge may cause some brief IFR conditions near KSNY by
11z. Area of showers will move from west to east across the area
Thursday morning and afternoon with MVFR conditions expected.
Temperatures may be cold enough for snow showers west of the
Laramie Range. Visibilities may be locally reduced in snow
showers. Gusty west winds of 20 to 25kt will develop behind the
front Wednesday morning near KLAR and KRWL.


Issued at 327 PM MDT Wed Apr 26 2017

Cool and moist pattern continues into the early part of the
weekend with no fire weather issues expected.


WY...Winter Weather Advisory until 6 PM MDT Thursday for WYZ112-114.



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