Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 261711
SWOMCD
SPC MCD 261711
WYZ000-261915-

Mesoscale Discussion 0843
NWS Storm Prediction Center Norman OK
1211 PM CDT Fri May 26 2017

Areas affected...Parts of southern Wyoming and adjacent northern
Colorado

Concerning...Severe potential...Watch possible

Valid 261711Z - 261915Z

Probability of Watch Issuance...60 percent

SUMMARY...Scattered thunderstorm activity is expected to continue to
initiate across the region through the 18-21Z time frame.  A few
supercells are expected to eventually evolve, accompanied by at
least some severe weather potential.  A watch is possible, though
most probable east of the Laramie Mountains later this afternoon.

DISCUSSION...Destabilization has already become sufficient to
support the initiation of thunderstorms near Rawlins.  This may be
supported by orographic influences, but low-level warm advection
focused along a west/east oriented baroclinic zone extending across
the region (downstream of the slow moving closed low centered over
southern Idaho) is probably contributing to more prominent forcing.
This seems likely to aid additional discrete storm development
across the Interstate 80 corridor of south central Wyoming into the
Laramie Mountains during the next few hours.

With further boundary layer destabilization, in the presence of
40-50+ kt southwesterly mid-level flow, the environment is expected
to become increasing conducive to the evolution of a few supercells.
 The most appreciable severe weather potential may begin to develop
along the eastern slopes of the Laramies, near/north of Cheyenne,
during the 19-21Z time frame, as moistening easterly near surface
flow and insolation begin to contribute to increasing boundary layer
instability across this region.

..Kerr/Hart.. 05/26/2017

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...CYS...RIW...

LAT...LON   41580881 42640630 41830416 41090461 41130614 41060855
            41580881



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