Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 142346
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
445 PM MST Wed Feb 14 2018

.SHORT TERM...(This evening through Friday Night)
Issued at 135 PM MST Wed Feb 14 2018

Tonight...Our High Wind Warning is verifying quite nicely with gusts
of 60 to 70 mph, and even a gust to 83 mph at Coleman on I-25 in
northern Platte County at 950 am. With the Craig to Casper 850/700
mb height gradients and low level wind speeds relaxing by this
evening, the 6 pm warning ending looks on track. Models indicate
snow to become more widespread across our Snowy and Sierra Madre
Ranges, thus the Winter Storm Warning looks good there.

Thursday...Shortwave trough aloft and its associated cold front plow
across our counties, with likely falling temperatures in the
afternoon. Will see snow chances during the day, with best chances
in orographically favored southwest mountains.

Thursday night...Clearing skies and much colder with 700 mb
temperatures down near -15 Celsius, yielding minimum temperatures in
the single digits.

Friday...Another quite windy day expected as the flow aloft remains
strong and the Craig to Casper 850/700 mb height gradients exceed 70
meters, thus likely producing high winds at wind prone and nearby
locations, similar to today. Colder temperatures compared to today
with 700 mb temperatures near -7 Celsius.

Friday night...Continued windy with orographic snows over the Snowy
and Sierra Madre Ranges, dry elsewhere.

.LONG TERM...(Saturday through Wednesday)
Issued at 135 PM MST Wed Feb 14 2018

Saturday...Windy and a little warmer per progged low and mid level
gradients and thickness trends.

Sunday...The flow aloft backs to west southwest with a shortwave
trough passage, as well as the next Canadian cold front plunging
southward into our northern counties. With the atmosphere becoming
more saturated, expect snow to spread slowly southward over our
northern counties during the day.

Monday...The holiday looks like a cold and snowy day with a cold
airmass in place, and moist southwest flow overrunning the cold
dome, producing widespread snow, which may be moderate to heavy at
times if the GFS verifies.

Tuesday...Snow chances decrease from west to east during the day as
the upper trough moves overhead and low level upslope decreases.
Quite cold with 700 mb temperatures progged near -20 degrees Celsius.

Wednesday...Strong zonal flow aloft produces a warming trend,
although warming will likely be limited by widespread snowpack
leftover from the Monday and Tuesday snows. Could again be quite
windy based on progged low and mid level gradients.

&&

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

Strong winds will gradually subside this evening from KRWL eastward
to KCYS, with gusts below 30 knots by 03Z. Severe mountain wave
turbulence may continue along and east of the Laramie Range through
midnight. Otherwise, VFR conditions expected with CIGS above 5000
feet AGL.

&&

.FIRE WEATHER...
Issued at 135 PM MST Wed Feb 14 2018

Minimal concerns based on projected winds and humidities.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...

WY...Winter Storm Warning until 6 PM MST Thursday for WYZ112-114.

     High Wind Warning until 6 PM MST this evening for WYZ101-104>107-
     109-110-115>118.

NE...None.
&&

$$

SHORT TERM...RUBIN
LONG TERM...RUBIN
AVIATION...TJT
FIRE WEATHER...RUBIN



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