Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 300556 AAA

Area Forecast Discussion...UPDATED
National Weather Service Cheyenne WY
1156 PM MDT FRI JUL 29 2016

Issued at 823 PM MDT Fri Jul 29 2016

Both Severe Thunderstorm Watches covering areas along and east of
I-25 have been cancelled over the past hour. Airmass stabilizing
quickly and convection weakening rapidly. Could still see a few
stray showers over SE Wyoming with a few remnant rumbles of
thunder across the northern NE Panhandle back west through
Niobraraand Converse counties through midnight...but chances for
severe storms and stronger convection diminishing rapidly. Update
forecast package has been issued.


.SHORT TERM...(Saturday through Sunday)
Issued at 1146 PM MDT Fri Jul 29 2016

Saturday...With less low and mid level moisture availability and
warmer temperatures at mid levels of the atmosphere, expect less
coverage of afternoon and evening thunderstorms along with warmer
temperatures at NAM and GFS guidance temperatures suggest.

Saturday night...A quieter night with minimal chance of showers and
thunderstorms due to lack of forcing mechanisms and lift. Boundary
layer progs suggest late night fog possible from Chadron to Sidney.

Sunday...A weak shortwave progged to move across northern Colorado
will combine with adequate mid level moisture to produce isolated
afternoon and evening thunderstorms, with limited coverage due to
relatively warm temperatures aloft near 16 Celsius. Warming trend
continues per thicknesses and warming temperatures aloft and have
compromised between the NAM and GFS MOS maximum temperatures.

.LONG TERM...(Sunday night through Friday)
Issued at 1146 PM MDT Fri Jul 29 2016

The subtropical upper high center to shift east from the Four
Corners to the south central Great Plains by midweek. The flow
aloft will become southwest, opening the door for some monsoonal
moisture. However, diurnal convective coverage will be isolated to
widely scattered at best and confined to the higher terrain and
portions of the plains. The ECMWF continues its wetter trend
compared to the GFS, and compromised. Monday and Tuesday will be
warmer than average with highs in the 80s to mid 90s. A rather
potent upper trough will track east along the northern tier CONUS
Wednesday which will push a cool front through the CWA. The flow
aloft will be more westerly which will cut off the monsoonal
moisture. Temperatures will moderate back to normal values for
early August with highs in the 80s.


.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1155 PM MDT Fri Jul 29 2016

Isolated showers will gradually dissipate later tonight. Otherwise,
VFR condiitons will prevail. There is the possibility for patchy
MVFR visibility fog invof Cheyenne between 10Z and 14Z. A weak
boundary will remain parked near the east slopes of the Laramie
Range through Saturday. Prevailing winds will be west-northwest
at Laramie and Rawlins, with south-southeast winds elsewhere.
Afternoon convection east of the Laramie Range will be more isolated
than Friday, and left out mention of VCTS for this TAF package.


Issued at 300 PM MDT Fri Jul 29 2016

No fire weather concerns through Saturday. However, daytime relative
humidities will lower through the weekend and wind gusts gradually
increase each day. By Sunday, we will be looking at elevated fire
weather concerns mainly along and west of Interstate 25.


.CYS Watches/Warnings/Advisories...


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