Mesoscale Discussion 1143
NWS Storm Prediction Center Norman OK
0710 PM CDT Wed Jun 19 2019
Areas affected...portions of southeast Missouri...central into
southern Illinois
Concerning...Severe potential...Watch unlikely
Valid 200010Z - 200215Z
Probability of Watch Issuance...5 percent
SUMMARY...Isolated severe may continue across the area through the
remainder of the late afternoon/early evening hours. Given the
sparse nature and short duration of the severe threat, a WW issuance
is not expected.
DISCUSSION...Discrete/semi-discrete storm development has recently
been noted across parts of eastern MO into central IL, where an
increasing trend in lightning production has been noted with the
more intense cells. Limited airmass recovery has occurred behind an
eastward propagating MCS, beneath a region of deep-layer ascent
provided by nearly-stacked surface-700 mb cyclone, where maximized
CVA has been noted. These storms are occurring within an environment
characterized by 1000-1500 J/kg MLCAPE and 30+ knots of bulk
effective shear, conducive to modest storm organization, with
marginally severe hail and perhaps a damaging wind gust or two
possible.
Within the past hour, a tornado was reported in northern Shelby
County, IL, where a relative maximum in both low-level ambient
vertical vorticity and 0-3km CAPE have been noted. Inflow dominant
storms in this regime may ingest the low-level vorticity/CAPE to
induce low-level rotation, perhaps supporting an additional brief
non-supercell or transient low-topped supercell tornado or two
before becoming outflow dominated.
Given the sparse and brief nature of the severe threat, a WW
issuance is not anticipated.
..Squitieri/Edwards.. 06/20/2019
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...PAH...ILX...LSX...
LAT...LON 37418838 37168920 36838993 36799054 36879106 38588997
39619007 40139054 39988873 39538794 38598797 37508833
37418838
Read morefrom SPC Forecast Products http://www.spc.noaa.gov/products/md/md1143.html
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