Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 281000

Area Forecast Discussion
National Weather Service Cheyenne WY
400 AM MDT Tue Mar 28 2017

.SHORT TERM...(Today thru Wednesday)
Issued at 400 AM MDT Tue Mar 28 2017

Issued a dense fog advisory for the Arlington area and southern
Laramie Range through 14Z as many WYDOT obs in these zones show vis
below one quarter mile.  We are currently seeing a break in the
precip across southeast WY, with light rain over the western
Nebraska Panhandle.  Models continue to show the upper trough
amplifying into the Four Corners region through the day, with a
midlvl closed low developing over northern New Mexico by this
evening.  Weak QG lift and upper level divergence will result in an
increasing coverage of precip across the CWA by late morning and
continuing through the evening.  The 00Z guidance does show less QPF
in general across the region compared to yesterdays runs, as the low
center is further south.  This is is a somewhat concerning trend for
snowfall amounts, as sfc temps are already marginal.

The main challenge with this event will be the snow level and
resulting impacts across southeast WY.  Models have been rather
consistent at showing wet bulb zero heights of 7000-7500 feet
through the day, that drop to around 6000 feet by later this
evening.  Not confident we will see snow accumulating on the road
surfaces through the afternoon outside of the mtns and southern
Laramie Range, especially considering the higher sun angle of late
March and not overly heavy snow rates.  This may change by the
evening as colder sfc temps and lack of solar radiation allow the
road sfc temps to cool to near freezing.  Overall, this looks like
an advisory level snow event for elevations above 7500 feet. Did
issue a Winter Storm Warning for the Snowy Range where accumulations
are highest.  Uncertainty over precip type was too great in the
elevation range of 6500-7500 feet (Shirley Basin, Laramie, South
Laramie Range foothills) to issue a Winter Weather Advisory.  Will
let the day shift monitor trends in these areas.  Precip will taper
off across the southern areas after around midnight.

.LONG TERM...(Wednesday night through Monday)
Issued at 400 AM MDT Tue Mar 28 2017

Stay in an unsettled pattern with low pressures systems tracking
to our south every 2-3 days. Looks like a pretty wet system Friday
into early Saturday. This one should be rain for most locations with
maybe snow above 7500 feet. Then another system for Sunday night
into Monday. The Sunday system looks colder and could be a
widespread snow event. Will continue to monitor.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1104 PM MDT Mon Mar 27 2017

Low pressure over New Mexico will give the area lower ceilings
through the next 24 hours. Colder temperatures will change rain
over to snow later this morning.


Issued at 400 AM MDT Tue Mar 28 2017

No fire weather concerns through this week with widespread
precipitation expected across the district along with cooler
temperatures. Looking at systems every 2-3 days that will drop
wetting rains and mountain snows through the middle of next week.


WY...Winter Storm Warning until 6 AM MDT Wednesday for WYZ114.

     Winter Weather Advisory until 6 AM MDT Wednesday for WYZ103-104-

     Dense Fog Advisory until 8 AM MDT this morning for WYZ110-116.



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