Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 180938

Area Forecast Discussion
National Weather Service Cheyenne WY
338 AM MDT Sun Mar 18 2018

.SHORT TERM...(Today through Monday)
Issued at 338 AM MDT Sun Mar 18 2018

Concerns will continue to be with expected snowfall across the CWA
this afternoon through early Monday, especially around the mtns of
southeast Wyoming. Currently quiet across the CWA ahead of an upper
trough with two circulation centers, one over western Montana and
the other over the southern Nevada area.  Expect the southern one
to provide the main impact on our weather later today into Monday
as it moves east, emerging over the southern Great Plains tonight
while strengthening. Lee cyclone will deepen over southeastern
Colorado today allowing for cooler air to push south across the
CWA. Should see increasing rain/snow over western parts of the CWA
later this morning into the afternoon, spreading out over the
plains this evening. Temps will be mild initially but as the
rain/snow move over temps should fall and allow a changeover to
all snow. Still appears the heaviest snow will be over the Snowy
Range through tonight with shadowing resulting in a little less
snow over the Sierra Madres. Decent snow still expected over the
Laramie Valley eastward across the summit area later today
through tonight with a general 3-6 inches expected. Current
warning/advys look good and will not change. Have opted to go with
an advy for the summit area as winds not looking quite as strong
thus blowing snow threat not as great. Main impacts will be on
travel, especially if a band of heavier snow progresses across
that area. Instabilities not as great with this system as the last
one. Snow will decrease later tonight as the system pulls away
with more isolated snow showers expected mainly around the mtns on

.LONG TERM...(Monday night through Saturday)
Issued at 338 AM MDT Sun Mar 18 2018

With the exception of some lingering snow showers in the Sierra
Madre and Snowy Ranges Tuesday, the midweek timeframe looks fairly
quiet before our next chance of snow comes in Thursday across the
higher elevations of our western areas. We see an increased
chance of precipitation by the weekend as a series of shortwaves
moves through the fast weset to southwesterly flow aloft.


.AVIATION...(For the 06Z TAFS through 06Z tonight)
Issued at 338 AM MDT Sun Mar 18 2018

Latest radar and satellite observations support current forecast
trends of Rawlins starting to drop to MVFR category after 15Z and
Laramie following by 18Z as a band of snow enhances on the
northwest side of the deepening low pressure over northern
Colorado. Snow this morning and afternoon along and west of the
Laramie Range will gradually shift east to affect Cheyenne by late
afternoon and the western Nebraska Panhandle this evining where we
advertise MVFR to IFR category tonight.


Issued at 338 AM MDT Sun Mar 18 2018

Fire weather concerns will be quite low for at least the next few
days with cool temperatures and additional snowfall over much of
the area. Drier and warmer conditions are expected by the middle
of the week.


WY...Winter Storm Warning from 9 AM this morning to 6 AM MDT Monday
     for WYZ114.

     Winter Weather Advisory from 9 AM this morning to 6 AM MDT
     Monday for WYZ112.

     Winter Weather Advisory from noon today to 6 AM MDT Monday for



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