ZCZC SPCSWOMCD ALL
ACUS11 KWNS 292138 
SPC MCD 292138 
NEZ000-SDZ000-292315-

Mesoscale Discussion 1303
NWS Storm Prediction Center Norman OK
0438 PM CDT Sat Jun 29 2019

Areas affected...Parts of northwestern Nebraska and southwestern
South Dakota

Concerning...Severe potential...Watch unlikely 

Valid 292138Z - 292315Z

Probability of Watch Issuance...20 percent

SUMMARY...It remains unclear how much longer isolated supercell
development will persist over parts of southwestern South Dakota. 
It still seems unlikely that a severe weather watch will be needed,
but trends will continue to be monitored.

DISCUSSION...The isolated supercell, which initiated around 20Z,
appeared to do so as somewhat cooler air surged southeast of the
Black Hills and locally enhanced convergence within lee surface
troughing to the south of the Badlands.  Along the axis of strongest
surface heating and deep boundary layer mixing, temperatures are
near 100F, with CAPE a relatively modest 1500-2000 J/kg.  The storm
appears embedded within generally light southwesterly deep layer
mean flow, but substantial veering of winds with height is
contributing to at least modest deep layer mean shear.  Still, due
substantial mid-level inhibition associated with a broad plume of
very warm elevated mixed-layer air, and generally lack of
appreciable large-scale forcing for upward vertical motion, it
remains unclear how much longer this cell will persist.

..Kerr/Thompson.. 06/29/2019

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

ATTN...WFO...LBF...UNR...

LAT...LON   43430228 43730198 43860157 43670101 43180119 42840152
            42710208 43080239 43430228 

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