Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 100656

Area Forecast Discussion
National Weather Service Cheyenne WY
1256 AM MDT Thu Aug 10 2017

.SHORT TERM...(This evening through Friday night)
Issued at 143 PM MDT Wed Aug 9 2017

Tonight...A passing shortwave trough aloft will help generate
scattered showers and isolated thunderstorms this evening, mainly
over our Wyoming counties, then spreading eastward later tonight.
Fortunately, CAPE is only around 500 J/kg, so storms should not be
as strong as yesterday`s storms. Perhaps some late night fog along
and west of Interstate 25 where the boundary layer shows near

Thursday...Copious amounts of low and mid level moisture remain
overhead and with daytime heating and a possible shortwave trough
aloft nearby, will again see scattered showers and isolated
thunderstorms in the afternoon. Compromised between the NAM and GFS
MOS maximums for high temperatures.

Thursday night...Showers and thunderstorms will come to an end in
the evening with the loss of daytime heating and absence of lifting

Friday...Similar scenario to Thursday with plenty of low and mid
level moisture and enough heating and low level upslope to generate
scattered showers and isolated thunderstorms in the afternoon.

Friday night...Showers and thunderstorms will gradually decrease in
areal coverage with loss of daytime heating and the absence of other
lifting mechanisms.

.LONG TERM...(Saturday through Wednesday)
Issued at 143 PM MDT Wed Aug 9 2017

Northwest flow and unsettled weather continues in the long term.
Clipper system moves through eastern Wyoming and western South
Dakota Saturday for fairly good precip chances over the Nebraska
Panhandle early Saturday that eventually spread to the Laramie
Range Saturday afternoon.

Upper ridge axis slowly moves east into western Wyoming Sunday
afternoon for mainly a dry day. Pretty warm temperatures as this
happens as 700mb temperatures climb to +12C. Should see highs in
the low 80s for low lying areas and mid to upper 70s elsewhere.

Ridge axis passes east of Wyoming into the Dakotas by Monday
evening with a shortwave trough approaching western Wyoming.
Surface front looks to move through southeast Wyoming Tuesday
afternoon with increased shower activity across the area.


.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1251 AM MDT Thu Aug 10 2017

Light to occasionally moderate shower activity will persist
through the early morning hours primarily east of KRWL. With the
low level flow becoming more northerly and northeasterly, expect
some stratus to develop through the early morning as well but with
ceilings remaining VFR. Some brief MVFR ceilings possible near
KCYS and KLAR but not confident enough to mention in the TAF at
this time. Current indications are that convection may take longer
to develop Thursday in the more stable air left over by this
mornings showers.


Issued at 143 PM MDT Wed Aug 9 2017

Minimal concerns due to expected rainfall as well as




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