SPC MD 1621

MD 1621 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR SOUTHERN LOWER MICHIGAN

Mesoscale Discussion 1621
NWS Storm Prediction Center Norman OK
0815 PM CDT Fri Aug 28 2020

Areas affected...Southern Lower Michigan

Concerning...Severe potential...Watch possible 

Valid 290115Z - 290345Z

Probability of Watch Issuance...40 percent

SUMMARY...Thunderstorms have increased in coverage and intensity
over Lake Michigan and are expected to pose a severe weather threat
as they move into southern Lower Michigan.  Convective trends will
be monitored for the possibility of a watch.

DISCUSSION...An upper-level impulse moving across southern Wisconsin
has aided the initiation of storms across Lake Michigan (including a
long-lived supercell).  These storms have increased in coverage and
intensity with time and are expected to persist as they move
eastward across Lower Michigan tonight.  Given a relatively
favorable kinematic and thermodynamic environment downstream, these
storms should remain organized (including transient supercell
structures), posing a severe weather threat.  Some surface-based CIN
is present (per current mesoanalysis) over southern Lower Michigan
given the stabilizing nocturnal boundary layer, but RAP forecast
soundings suggest effective layer inflow parcels are likely to
originate from the surface.  Thus, damaging winds are possible along
with hail, and a tornado cannot be ruled out.  Convective trends
will be monitored for the possibility of a watch.

..Jirak/Guyer.. 08/29/2020

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

ATTN...WFO...DTX...IWX...GRR...

LAT...LON   43198630 43588628 43698546 43628475 43298384 42728317
            42358295 42068326 41878390 41818474 41958594 42158616
            42228628 42608619 42998619 43198630 

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from SPC Forecast Products http://www.spc.noaa.gov/products/md/md1621.html