Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 240330

Area Forecast Discussion
National Weather Service Cheyenne WY
930 PM MDT Tue May 23 2017

.SHORT TERM...(This evening through Thursday night)
Issued at 208 PM MDT Tue May 23 2017

Isolated light showers dotting mainly the Neb Panhandle this
afternoon on far west side of upper low over Iowa. Expect these to
dissipate by early this evening and skies to subsequently clear
over the CWA with a clear and somewhat cool night.

A short upper ridge will pass across the region Weds boding for
warmer and dry weather with mainly clear skies. Max temps should
rise well into the 70s over the plains and even around 80 in parts
of the North Platte River valley. Warmth short-lived though as an
upper trough will drop into the Pacific northwest Wednesday and
extend into the northern plains by late Thursday. This will push a
cool front across the CWA early Thursday morning and cool max
temps Thursday about 10-15 degrees. Weak impulses coming through
the base of the trough will help to produce sctd showers and a few
daytime storms over mainly the southern parts of the CWA Wednesday
night through Thursday night.

.LONG TERM...(Friday through Tuesday)
Issued at 208 PM MDT Tue May 23 2017

Friday-Friday night:
This timeframe looks rather interesting for strong/svr storm
chances. The main question will be the position of the surface
low/lee side trof. The GFS is bringing in the deeper low level
moisture as far north as I-80 while the ECMWF/GEM and ensembles
are showing the deeper moisture further south. Each of these
models drives a piece of energy through the base of the strong
upper level trof centered in Canada. There is also some
enhancement from the right entrance region of the upper level jet.
If the plays out we could be looking at a decent rainfall event
Friday afternoon into Friday night across southern Wyoming and the
southern Nebraska panhandle. If the GFS verifies, we could see a
higher risk of heavier rainfall and strong to severe storms, due
to plenty of shear in place. However, if the ECMWF/NAEFS/GEM
verifies most of the heaviest precip./stronger storms will be
south of the CO/WY border. Either way it looks like a good shot of
rainfall for these areas.

Behind this strong shortwave, we will be looking at another period
of cyclonic curvature and periodic shortwaves rotating on the
back side of the closed upper level low moving into the northern
Plains. As a result, most of the area will see a chance of
afternoon showers and isolated thunderstorms on Saturday. The
chance of afternoon showers and isolated thunderstorms will
gradually shift east through the remainder of the period, but
conditions will remain cool with a gradual warmup through Tuesday.


.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 928 PM MDT Tue May 23 2017

Wyoming TAFS...VFR. Wind gusts from 30 to 35 knots from 15Z to 01Z

Nebraska TAFS...VFR. Wind gusts from 23 to 26 knots from 15Z to
01Z Wednesday.


Issued at 208 PM MDT Tue May 23 2017

Fire weather concerns will remain low for the rest of the week
with non-critical fuels and weather conditions persisting. Warmer
and dry weather for Wednesday then cooler with chances for rain
for the rest of the week.


Issued at 230 PM MDT Tue May 23 2017

No significant concerns anticipated in the short term. Warm
temperatures Wednesday will increase snow melt and resultant
runoff but much of the snow over lower elevations has already
melted. Cooler temperatures beginning Thursday will slow melt and




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