ZCZC SPCSWOMCD ALL
ACUS11 KWNS 040606 
SPC MCD 040606 
KYZ000-INZ000-TNZ000-ILZ000-MSZ000-MOZ000-ARZ000-040800-

Mesoscale Discussion 0516
NWS Storm Prediction Center Norman OK
0106 AM CDT Tue May 04 2021

Areas affected...southeastern Missouri...southern
Illinois...southwestern Indiana...eastern Arkansas...western
Tennessee

Concerning...Severe potential...Watch likely 

Valid 040606Z - 040800Z

Probability of Watch Issuance...95 percent

SUMMARY...Severe risk will gradually increase across Mid Mississippi
and lower Ohio Valleys, as convection expands/spreads eastward.  A
WW will be required.

DISCUSSION...Latest radar loop shows a large MCS -- comprised of a
well-organized bowing band of storms moving eastward across northern
and central Arkansas, and several smaller clusters of intense
convection to the southwest.

Ahead of the convection, a very unstable airmass -- characterized by
mixed-layer CAPE in excess of 2500 J/kg -- exists, in advance of the
cold front crossing Missouri/Oklahoma/eastern Texas at this time. 
As this front -- and the associated upper trough crossing
Kansas/Oklahoma/Texas -- progress, risk for damaging winds and hail
will spread across the Mid Mississippi Valley area, with convective
intensity aided by stronger flow spreading across the region ahead
of the upper system.  With the Arkansas bowing segment nearing
northeastern portions of WW 137, a new watch -- across the lower
Ohio Valley area and adjacent portions of the Mid Mississippi Valley
-- will be needed within the next hour.

..Goss/Guyer.. 05/04/2021

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

ATTN...WFO...LMK...OHX...PAH...MEG...LSX...LZK...

LAT...LON   37109069 37639053 38248865 38268724 37498709 35328772
            34898898 34949019 34969162 37109069 

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