Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 282123 CCA

Area Forecast Discussion...Corrected Long Term
National Weather Service Cheyenne WY
319 PM MDT Fri Apr 28 2017

.SHORT TERM...(This evening through Sunday)
Issued at 319 PM MDT Fri Apr 28 2017

Snow continuing over much of the area this afternoon but a very
narrow dry wedge of air at mid atmospheric levels has held over
far southern parts of the CWA and kept pcpn away in areas such as
Cheyenne to Laramie. Snow has had difficulty sticking as well
due to marginal temperatures and high Sun angle with most roadways
just wet.

The upper low responsible for the pcpn is deepening over eastern
Utah and is expected to drop south then southeast into central New
Mexico through Saturday morning then move east into the southern
plains Saturday night then slowly northeast on Sunday. This track
will pull pcpn southward overnight with pcpn expected to come to
an end across the CWA by Saturday afternoon. A few inches of
snowfall still expected mainly over the southern mtns tonight with
lighter snows elsewhere thus have made some modifications to
highlights through this evening in view of this.

Dry weather expected over the CWA late Saturday through Sunday as
a narrow upper ridge moves over the area on the back side of the
plains upper low.

.LONG TERM...(Sunday night through Friday)
Issued at 319 PM MDT Fri Apr 28 2017

The 12Z medium range models and their ensembles are in reasonable
agreement with the large scale pattern. Upper closed low and the
associated trough over the eastern Great Plains/MS Valley early in
the period lifts northeast across the Great Lakes, OH valley and
Northeast by Wednesday. A progressive northwest flow aloft will
dominate the Rockies and plains through mid-week, with a couple of
Alberta clipper low pressure systems producing scattered rain/snow
showers and gusty northwesterly winds through mid-week. Snowfall
over the higher elevations will be light to moderate with
potentially several inches during this time period. Below normal
temperatures are forecast for Monday through Wednesday with highs in
the 40s and 50s lower elevations and 30s mountains. A high amplitude
upper ridge along the Pacific coast will shift east across the
Intermountain West and Rockies late next week, bringing drier
conditions and warmer than normal temperatures.


.AVIATION...(For the 18Z TAFS through 18Z Saturday morning)
Issued at 1110 AM MDT Fri Apr 28 2017

Cold front was located along a KRWL-KLAR-KCYS-KSNY line at 17Z and
will continue its slow southward motion. Convective banding of
precipitation behind the front, mostly in the form of snow, will
make slow southward progress through the afternoon. Periods of LIFR
or lower visibility will occur with the heavier snow bands, with
prevailing MVFR-IFR conditions through tonight in moist northeasterly
upslope flow.


Issued at 319 PM MDT Fri Apr 28 2017

No fire weather concerns seen into at least early next week with
fuel and weather conditions remaining mostly non-critical.


WY...Winter Storm Warning until midnight MDT tonight for WYZ104-114.

     Winter Weather Advisory until midnight MDT tonight for WYZ103-

     Winter Weather Advisory until 9 PM MDT this evening for WYZ101.




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