MESOSCALE DISCUSSION 0635
   NWS STORM PREDICTION CENTER NORMAN OK
   1047 AM CDT FRI APR 11 2008
   
   AREAS AFFECTED...NRN IND...SRN/CNTRL LOWER MI...NWRN OH
   
   CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY 
   
   VALID 111547Z - 111715Z
   
   THE THREAT FOR DISCRETE SURFACE-BASED SUPERCELLS WILL LIKELY
   INCREASE AS THE AIR MASS DESTABILIZES AHEAD OF A COLD FRONT...WITHIN
   A VERY STRONGLY SHEARED ENVIRONMENT. A TORNADO WATCH ISSUANCE
   APPEARS PROBABLE AROUND 17-18Z.
   
   15Z SUBJECTIVE SURFACE ANALYSIS PLACES A NWD-MOVING W TO E ORIENTED
   WARM FRONT ACROSS SRN LOWER MI TO A TRIPLE POINT IN FAR SERN
   WI...WITH AN EWD-MOVING COLD FRONT ARCING SWD ALONG THE IL/IND
   BORDER. RECENT VIS IMAGERY DEPICTS LITTLE CLOUDINESS TO HINDER
   INSOLATION WITHIN THE OPEN WARM SECTOR. THIS COUPLED WITH A ZONE OF
   STEEP MID-LEVEL LAPSE RATES ROTATING E OF UPPER MS RIVER VALLEY
   UPPER LOW /AS SAMPLED BY 12Z ILX RAOB/...WILL RESULT IN AT LEAST A
   MARGINALLY UNSTABLE AIR MASS WITH MLCAPES APPROACHING 1000 J/KG.
   KINEMATIC FIELDS ARE INTENSE...110 KT SWLY 500 MB JET SHIFTING NEWD
   FROM SERN MO/SRN IL INTO SRN IND/SWRN OH BY THIS AFTERNOON...AND A
   40-45 KT SLY LLJ SAMPLED BY WOLCOTT IND PROFILER. WITH DEEP-LAYER
   SHEAR ORIENTED NEARLY PERPENDICULAR TO THE FORCING BOUNDARY /I.E.
   COLD FRONT/...DISCRETE SUPERCELLS APPEAR MORE PROBABLE VERSUS A
   MULTICELLULAR LINEAR BAND. GIVEN THIS AND THE STRENGTH OF THE
   LOW-LEVEL WIND PROFILE...LARGE HAIL AND A FEW TORNADOES WILL BE
   POSSIBLE...AND A 10 PERCENT TORNADO PROBABILITY WILL BE REINTRODUCED
   INTO THE 1630Z DAY 1 OUTLOOK.
   
   ..GRAMS.. 04/11/2008
   
   
   ATTN...WFO...CLE...ILN...DTX...IWX...GRR...IND...LOT...
   
   41428323 40888409 40398558 40378661 40748704 41388687
   42308643 43398619 43608501 43788401 43828299 43348245
   42438267