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596
FXUS65 KCYS 240415 AAA
AFDCYS

Area Forecast Discussion...UPDATED
National Weather Service Cheyenne WY
1015 PM MDT FRI SEP 23 2016

.UPDATE...
Issued at 848 PM MDT Fri Sep 23 2016

Cancelled Severe Thunderstorm Watch early this evening as better
shear and instability moved northeast into western SD. There were
several reports of large hail and damaging winds across portions
of eastern WY and the northern NE panhandle during the late
afternoon. A strong cold front pushed east of the CWA this evening,
with some thunderstorms lingering over the NE panhandle until
midnight. Otherwise, occasional showers will continue tonight.
Temperatures will be cold enough for snow above 9000 feet, however
little or no accumulation is expected. West to northwest winds
will remain rather gusty tonight due to the tight post-frontal
pressure gradient.

&&

.SHORT TERM...(This evening through Sunday night)
Issued at 215 PM MDT Fri Sep 23 2016

Active weather pattern across the CWA early this period with
showers and thunderstorms...some strong or even severe...along
with some mtn snows. All this in association with a strong upper
low currently beginning to lift northeast around the Utah/Wyoming
border. band of showers and a few storms now progressing into
central Wyoming and this will continue to move slowly east through
this evening with individual showers and storms in this band moving
quickly north. Some potential for a few strong to severe storms
the rest of this afternoon given modest CAPE values and good
shear. Strong winds the main threat given the fast speeds of any
storms with some marginally severe hail possible as well. Activity
will move into the high plains tonight as the upper low moves
northeast across Wyoming. On Saturday the upper low will move
over the northern plains with downsloping flow expected to dry
things out east of the mtns. Wrap-around moisture will bring some
rain and snow showers to western parts of the CWA with a few
inches of snow over the higher mtns mainly saturday morning. All
pcpn should end Saturday evening as the upper low moves over North
Dakota and the main trof axis moves by the area. Cool saturday
night with dry and mild weather on Sunday.

There also could be a relatively short period of stronger winds in
the wind-prone areas of southeast Wyoming Saturday morning. Will
hold off on a watch as speeds look marginal relatively localized
only for a short time. Still...some gusts around 50 mph possible.

.LONG TERM...(Monday through Friday)
Issued at 215 PM MDT Fri Sep 23 2016

A transition to warmer and drier weather is expected through most of
the extended forecast period as upper-level ridging builds back into
the area. The GFS and ECMWF both suggest a weak trough under-cutting
the ridge and lifting across the central Rockies on Wednesday and/or
Thursday, possibly resulting in isolated showers and
thunderstorms.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1013 PM MDT Fri Sep 23 2016

Showers will continue overnight, producing occasional MVFR cig/vis.
Gusty northwest to west winds 25-35 kt will continue as well. Brief
-TSRA will impact the western Nebraska terminals until 08Z. Cig/vis
improve to VFR east of the Laramie Range by morning, with MVFR cig
persisting at RWL thru the day. Scattered showers will be possible
west of the Laramie Range Saturday with VCSH at RWL and LAR. West
winds will gust 25-30 kt Saturday.

&&

.FIRE WEATHER...
Issued at 215 PM MDT Fri Sep 23 2016

Overall fire weather concerns expected to remain low through the
weekend into early next week. A cold front will move across the
district through this evening with a band of showers and
thunderstorms accompanying it. Breezy and cooler Saturday with
mild and mainly dry weather expected Sunday into early next week.

&&

.CYS Watches/Warnings/Advisories...
WY...None.
NE...None.
&&

$$

UPDATE...MAJ
SHORT TERM...RE
LONG TERM...CLH
AVIATION...MAJ
FIRE WEATHER...RE