ZCZC SPCSWOMCD ALL
ACUS11 KWNS 071607 
SPC MCD 071607 
OHZ000-MIZ000-INZ000-071730-

Mesoscale Discussion 1178
NWS Storm Prediction Center Norman OK
1107 AM CDT Wed Jul 07 2021

Areas affected...Southern Lower MI...northern OH...northeast IN

Concerning...Severe potential...Watch likely 

Valid 071607Z - 071730Z

Probability of Watch Issuance...80 percent

SUMMARY...Thunderstorms are expected to increase in coverage this
afternoon, with clusters of strong/severe storms posing a risk for
primarily damaging winds.  A few instances of hail will also be
possible.  A Severe Thunderstorm watch will likely be needed by 18z.

DISCUSSION...Strong daytime heating continues south of an east-west
stationary front, a segment of which extends from southern Ontario
Province to southern lower MI and southeast IA.  With minimal MLCIN
and moderate/pockets of strong instability developing by early-mid
afternoon, thunderstorms are expected to develop over the next few
hours and move generally east.  Effective shear values across the
area will average 20 and 30 kts, supporting primarily a
multicellular/cluster storm mode.  Steep low-level lapse rates and a
very moist environment will result in a risk for damaging downburst
winds with storms and clusters this afternoon.  Although weak
mid-level lapse rates and modest effective shear will limit large
hail potential, isolated stronger updrafts may produce instances of
severe hail.

Observational trends will be monitored and a Severe Thunderstorm
Watch will likely be needed by 18z.

..Bunting/Guyer.. 07/07/2021

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

ATTN...WFO...PBZ...CLE...ILN...DTX...IWX...GRR...

LAT...LON   42388535 42768387 42538281 42228317 41878315 41648260
            42018176 42188137 42108066 41238058 40558073 40238149
            40308281 40448411 40578514 41018575 41658589 42388535 

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