ZCZC SPCSWOMCD ALL
ACUS11 KWNS 272328 
SPC MCD 272328 
IAZ000-NEZ000-280100-

Mesoscale Discussion 1621
NWS Storm Prediction Center Norman OK
0628 PM CDT Fri Aug 27 2021

Areas affected...far eastern NE...west-central IA

Concerning...Severe potential...Watch possible 

Valid 272328Z - 280100Z

Probability of Watch Issuance...40 percent

SUMMARY...Isolated large hail and severe gusts are possible with the
more intense thunderstorms this evening.  Overall storm coverage is
still uncertain (i.e., isolated) and the lower storm coverage may
preclude a severe thunderstorm watch being issued, although the
stronger storms will potentially be capable of severe weather given
the favorable environment.

DISCUSSION...Visible-satellite imagery shows developing convection
over far eastern NE into west-central IA on the trailing portion of
a mid-level shortwave trough migrating east-northeastward over the
Upper Midwest.  Surface conditions are hot and humid with
temperatures in the lower 90s with lower 70s dewpoints.  The RAP
forecast sounding for Omaha, NE shows a good depiction of the
surface conditions and it indicates around 3300 J/kg MLCAPE. 
Although flow is relatively modest in the lowest 9 km per KOAX 88D
VAD data (sub 30 kt), 25-30 kt effective shear is indicated and
would in turn support organized storm structures this evening.  The
main threats with the stronger storms would be a hail/wind threat.

..Smith/Bunting.. 08/27/2021

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

ATTN...WFO...DMX...FSD...OAX...

LAT...LON   41319663 42129588 42589525 42659446 42359396 41819414
            41149559 40929619 41319663 

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