Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 222348
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
445 PM MST Mon Jan 22 2018

.SHORT TERM...(Tonight - Tuesday Night)
Issued at 218 PM MST Mon Jan 22 2018

Strong & gusty winds have been occurring in the southeast Wyo wind
corridors this afternoon. Bordeaux became sustained near 45 MPH in
the late morning hours, prompting the issuance of a near-term High
Wind Warning until 6 PM this evening w/ model progs showing 800 mb
flow holding steady through the afternoon. Recent WYDOT obs show a
decreasing trend with sustained winds now around 35 MPH, so expect
we will cancel this soon as peak mixing has passed. Not much of an
issue with blowing snow today despite frequent gusts between 45-50
MPH, overall more drifting creating the sheeting of ice. The worst
conditions have consistently been along I-25 near Bordeaux. Warmer
temps this afternoon have mitigated the blowing/drifting, thus the
decision was made to let the Winter Wx Adzy expire despite some of
our area roads remaining closed or in very poor shape.

Another marginal high wind episode is possible Tuesday night, into
the day on Wednesday. Despite low-level CAG to CPR gradients of 55
to 65 meters advertised by both the GFS and NAM, there is just not
much going for the pattern other than strong subsidence and strong
(50+ knot) flow at H7-H8. Our confidence is too low to warrant the
issuance of a High Wind Watch right now, but did maintain forecast
wind speeds near Warning criteria with gusts around 55 MPH.

.LONG TERM...(Wednesday through Sunday)
Issued at 458 AM MST Mon Jan 22 2018

High wind potential continues across the southeast Wyoming Wind
corridor into Wednesday. Otherwise, a transitory ridge will build
keeping conditions and temperatures warming into the 40s for
Wednesday and Thursday. Both the GFS/ECMWF have trended weaker
for the progressive late week system, mainly just targeting the
higher terrain Thursday night and Friday. Nonetheless, several
inches of accumulation will be possible mainly over the Snowy,
Sierra Madre, and northern Laramie Ranges. Cold fropa will cool us
back into the 30s for Friday and Saturday.

&&

.AVIATION...(For the 00Z TAFS through Tuesday afternoon)

VFR conditions expected at all terminals with relatively light
winds. Some midlevel cloudiness will impact KRWL tonight, but CIGS
should remain above 5000 feet AGL.

&&

.FIRE WEATHER...
Issued at 218 PM MST Mon Jan 22 2018

No fire weather concerns due to recent significant snowfall across
a large part of the region. Breezy to locally windy conditions are
expected to result in areas of blowing and drifting snow from time
to time. Temperatures warm back into the 40s for Wed/Thu, with the
next chance of snow returning to the mountains Thu night/Fri.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Warning until 6 PM MST this evening for WYZ106.

NE...None.
&&

$$

SHORT TERM...CLH
LONG TERM...JG
AVIATION...TJT
FIRE WEATHER...CLH


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