Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 141745

Area Forecast Discussion
National Weather Service Cheyenne WY
1045 AM MST Sat Jan 14 2017

.SHORT TERM...(Today - Monday)
Issued at 245 AM MST Sat Jan 14 2017

A strong surface high remains intact across southeast Wyoming, and
the western Nebraska Panhandle early this morning. We expect areas
of fog to develop in the next few hours w/ abundant boundary layer
moisture and light winds along and west of the Laramie Range. HRRR
guidance suggests potential for dense fog, so continued to mention
that in the grids through 18z. Morning water vapor satellite shows
a strong upper low spinning near the northern Baja coast-line. The
models bring this feature east-northeast just south of the Mexico-
Arizona border through 12z Sunday. Meanwhile, a persistent surface
high will likely contribute to another round of fog for areas west
of the Laramie Range on early Sun morning. The aforementioned area
of low pressure will lift northeast along the Texas and New Mexico
border on Sunday, and is progged to be over the northern Panhandle
of Texas by 06z Monday. The ECMWF remains the northernmost soln of
the model spectrum, and would support deformation zone snow across
our southeastern zones as early as Sunday late afternoon. The GFS/
ECMWF are in decent agreement with the track of the surface low in
eastern Kansas during the Sunday night - Monday time frame. A wave
tracking across the Dakotas is expected to favor the eastern track
of the low, so at this time do not expect significant winter storm
impacts in our CWA. At the worst, this storm looks to graze a part
of the southern NE Panhandle if the ECMWF verifies. Otherwise, the
GFS and NAM both have little (if any) QPF. Continued w/ a 1-2 inch
forecast over mainly Cheyenne county, otherwise up to about a half
inch along and southeast of a CYS-AIA line. This lines up with WPC
and neighboring WFOs nicely.

.LONG TERM...(Monday Night through Friday)
Issued at 245 AM MST Sat Jan 14 2017

Dry and milder weather will set up across the CWA Tuesday into
Thursday as an upper ridge moves over the region and gradually
flattens. Some shortwave energy riding to north of the area wl
help to enhance lee troughing at times thus some breezy to windy
areas are likely especially around the mountains Weds and Thurs.
Meanwhile the next upper trough will move onshore over the western
CONUS Thursday then some energy will eject east across the Rockys
Friday bringing a Pacific cool front across the CWA as well as
some snow showers...mainly around the mtns. Models in pretty good
agreement with this scenario through Friday then diverge after


.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1045 AM MST Sat Jan 14 2017

Main impacts to aviation operations will be at KRWL and KLAR
terminals, where low clouds and fog linger and/or develop. KRWL is
expected to lift to VFR this afternoon, before droppiing back into
IFR after 07Z. KLAR has already lifted this morning and will
remain VFR this afternoon, before returning to IFR 08-15Z. VFR
conditions will prevail elsewhere with just some increasing clouds
today and tonight. KSNY and KBFF may begin to see lowering CIGS
back to MVFR after 14Z as the next storm system approaches from
the southwest.


Issued at 245 AM MST Sat Jan 14 2017

Minimal fire weather concerns this weekend with the combination of
high humidity values and light winds.





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