MESOSCALE DISCUSSION 0725
   NWS STORM PREDICTION CENTER NORMAN OK
   1134 AM CDT MON MAY 20 2013
   
   AREAS AFFECTED...LOWER MI
   
   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 
   
   VALID 201634Z - 201730Z
   
   PROBABILITY OF WATCH ISSUANCE...80 PERCENT
   
   SUMMARY...COVERAGE OF TSTMS SHOULD INCREASE THROUGH THE EARLY
   AFTERNOON ACROSS WRN LOWER MI...AND MAY EVENTUALLY CONSOLIDATE AND
   SPREAD EWD OVER THE REMAINDER OF LOWER MI LATER THIS AFTERNOON. AN
   INITIAL THREAT OF DMGG WIND GUSTS...LARGE HAIL...AND PERHAPS A
   BRIEF/WEAK TORNADO WILL EXIST AS ACTIVITY REMAINS
   SEMI-DISCRETE...BUT SHOULD EVOLVE INTO PRIMARILY A DMGG WIND THREAT
   WITH TIME. A WW WILL LIKELY BE NEEDED WITHIN THE NEXT HOUR.
   
   DISCUSSION...STRONG HEATING IS OCCURRING ACROSS LOWER MI WITHIN A
   MOIST BOUNDARY LAYER...CHARACTERIZED BY SFC DEW POINTS IN THE UPPER
   60S F...CONTRIBUTING TO ESTIMATED MLCAPE VALUES OF 1500-2500 J/KG. A
   RIBBON OF MIDLEVEL MOISTURE PRECEDING A LARGE NRN PLAINS TROUGH WAS
   NOTED ON WATER VAPOR MOVING EWD ACROSS LAKE MI. AS THIS INTERSECTS
   WEAK LOW-LEVEL CONVERGENCE ALONG A DEVELOPING SFC TROUGH NEAR THE
   ERN SHORE OF LAKE MI...TSTMS SHOULD RAPIDLY DEVELOP. MODERATELY
   STRONG BUT UNIDIRECTIONAL VERTICAL WIND PROFILES ORIENTED NEARLY
   PARALLEL TO INITIATING LINE SHOULD PROMOTE MULTIPLE CELL
   INTERACTIONS INITIALLY...BEFORE CONSOLIDATION INTO CLUSTERS OR A
   QLCS OCCURS. THIS SHOULD PROPAGATE EWD ACROSS LOWER MI...POSING A
   PRIMARY THREAT OF DMGG WINDS...ALTHOUGH SOME HAIL THREAT WILL ALSO
   EXIST GIVEN THE DEGREE OF INSTABILITY PRESENT.
   
   ..ROGERS/KERR.. 05/20/2013
   
   
   ATTN...WFO...DTX...APX...IWX...GRR...
   
   LAT...LON   42648280 42158325 41898399 41758500 42018579 42928620
               43848603 44748600 45378534 45668491 45698433 45308361
               43938284 42648280