MESOSCALE DISCUSSION 0974
   NWS STORM PREDICTION CENTER NORMAN OK
   0352 PM CDT THU JUN 11 2015

   AREAS AFFECTED...NERN ILLINOIS...SRN LOWER MICHIGAN...NRN
   INDIANA...NWRN OHIO

   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

   VALID 112052Z - 112245Z

   PROBABILITY OF WATCH ISSUANCE...40 PERCENT

   SUMMARY...IT IS NOT YET CERTAIN THAT A SEVERE WEATHER WATCH WILL BE
   NEEDED LATE THIS AFTERNOON...BUT CONVECTIVE TRENDS ARE BEING
   MONITORED FOR THE POSSIBILITY OF AN INCREASING SEVERE WEATHER
   THREAT.

   DISCUSSION...A STALLED LOW-LEVEL BAROCLINIC ZONE ACROSS SOUTHERN
   PORTIONS OF THE GREAT LAKES REGION IS BECOMING THE FOCUS FOR
   INCREASING THUNDERSTORM DEVELOPMENT.  AT THE CURRENT TIME...THIS
   APPEARS MAINLY WHERE LAKE BREEZES ARE ENHANCING LOW-LEVEL
   CONVERGENCE...IN THE PRESENCE OF MODERATE BOUNDARY LAYER CAPE ON THE
   ORDER OF 2000 J/KG.  LARGE-SCALE FORCING FOR UPWARD VERTICAL MOTION
   REMAINS WEAK /UNCLEAR...AND IS GENERALLY NOT EXPECTED TO INCREASE
   UNTIL LATER TONIGHT.  HOWEVER...DESPITE THE RATHER WEAK TO MODEST
   STRENGTH OF THE LOW-LEVEL WIND FIELDS...DEEP LAYER SHEAR BENEATH
   30-40 KT WESTERLY MID-LEVEL FLOW IS SUFFICIENT FOR ORGANIZED
   CONVECTIVE DEVELOPMENT...AND COULD ENHANCE ONGOING ACTIVITY IN THE
   PEAK LATE AFTERNOON HEATING.  STRONGER ACTIVITY MAY BECOME CAPABLE
   OF PRODUCING STRONG WIND GUSTS AND SOME HAIL...BUT IT MAY NOT BE OUT
   OF THE QUESTION THAT SURFACE BOUNDARY INTERACTIONS COULD CONTRIBUTE
   TO AN ISOLATED TORNADO OR TWO.

   ..KERR/HART.. 06/11/2015


   ATTN...WFO...CLE...ILN...IWX...GRR...LOT...DVN...

   LAT...LON   41978831 41938774 41868638 42238614 41618449 41198332
               40778379 40848611 40638788 41268922 41778897 41978831