Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 160958

Area Forecast Discussion
National Weather Service Cheyenne WY
258 AM MST Mon Jan 16 2017

.SHORT TERM...(Today through Wednesday)
Issued at 131 AM MST Mon Jan 16 2017

An area of light snow and/or freezing rain continues to pivot from
the southern Nebraska Panhandle into far southeastern Wyoming this
morning. Snow is having a hard time pushing west into the southern
Laramie Range, likely due in part to dry north-northwest flow near
the surface. Any lingering threat of freezing rain along I-80 from
Sidney to Kimball should end soon as forecast soundings still show
cooling profiles through the night, but any snow on top of the ice
that has already accumulated will yield hazardous travel. The GFS/
NAM/ECMWF/GEM all show light precipitation backing further into WY
from 09z to 12z, then decreasing from NW-SE through 15z and ending
for all areas by 18z. HRRR composite reflectivity suggests this as
well. Additional snow accumulations should generally be an inch or
less, mainly over the southern Nebraska Panhandle. The Winter Adzy
for Snow/Freezing rain still looks good but expect we will be able
to cancel it early. Dry after today as the models show the central
Rockies in the middle of a split flow pattern w/ all of the energy
being pushed to the north or south on Tuesday. Low-level gradients
are progged to increase on Wednesday with lee side troughing under
divergent flow aloft. Breezy/windy conditions can be expected over
the Laramie Range and perhaps the adjacent plains as well, but the
winds aloft appear a bit too weak to support a warning-level event
for the BRX/VDW areas. Excellent downslope warming is expected for
Wednesday with all models showing 700 mb temperatures ranging from
+2 to +5 deg C, so opted to go several degrees above consensus MOS

.LONG TERM...(Wednesday night through Sunday)
Issued at 330 AM MST Mon Jan 16 2017

Pretty tranquil in the extended with dry weather, light winds and
seasonal temperatures. Next system to impact the area looks to be
Friday when a low pressure system tracks across Colorado. Pretty
faster mover, so not a lot of snow expected with this system.


.AVIATION...(For the 06Z TAFS through Monday Evening)

Main aviation concern is freezing rains across the southern Nebraska
panhandle and some light snow pushing towards KBFF...KAIA...and KCYS
tonight. Expect MVFR CIGS and VIS over the next few hours. Believe
there will be a period of IFR as the more intense bands of precip
move northward across the area after midnight. Freezing rain should
change over to all snow after midnight near KSNY as colder air aloft
begins moving into the area. There will be icing concerns through at
least 08z tonight before the colder air moves into the area.
Otherwise...LIFR conditions and fog will persist around Rawlins
through midnight...but there are some indications that fog may
dissipate between midnight and 09z resulting in slowly improving
conditions. Do not expect fog to develop over KLAR
removed from the TAF but kept an MVFR CIGS around 1500 to 2500 feet


Issued at 131 AM MST Mon Jan 16 2017

No fire weather concerns over the next several days with afternoon
RH values well above critical thresholds.



NE...Winter Weather Advisory until noon MST today for NEZ054-055.



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