Mesoscale Discussion 1254
NWS Storm Prediction Center Norman OK
0104 AM CDT Tue Aug 07 2018
Areas affected...Portions of the mid Mississippi valley
Concerning...Severe potential...Watch unlikely
Valid 070604Z - 070700Z
Probability of Watch Issuance...5 percent
SUMMARY...A few damaging gusts remain possible early this morning.
However, the threat is forecast to diminish over the next couple of
hours, and watch issuance is not expected.
DISCUSSION...A small, but robust convective cluster has produced
occasional wind damage over eastern Missouri this morning as it
moves east around 40-45 kt. Enhanced convergence and focused
propagation along outflow to its east are likely maintaining the
severe threat more than would be expected otherwise, considering the
presence of non-negligible surface-based inhibition. Still, the ILX
00Z sounding sampled relatively steep lapse rates, such that some
residual mixed layer (atop a thin, nocturnally cooled surface layer)
is aiding updraft accelerations for parcels forced to their LFC by
the cold pool. With that said, this cluster and a small linear
segment to the north in Illinois should become increasingly
displaced behind surging outflows this morning, with the the
damaging-wind threat diminishing accordingly.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 39209186 40898978 40718835 40098805 38888876 38588965
38789147 38999187 39209186