MESOSCALE DISCUSSION 1598
   NWS STORM PREDICTION CENTER NORMAN OK
   0218 PM CDT MON AUG 03 2015

   AREAS AFFECTED...PORTIONS OF SERN IND...CNTRL/SRN OH...FAR NRN KY

   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

   VALID 031918Z - 032115Z

   PROBABILITY OF WATCH ISSUANCE...40 PERCENT

   SUMMARY...THUNDERSTORMS SHOULD GRADUALLY EXPAND IN COVERAGE ACROSS
   THE REGION THIS AFTERNOON...WITH SOME POTENTIAL FOR DAMAGING WIND
   GUSTS AND A FEW LARGE HAIL REPORTS. CONVECTIVE TRENDS WILL BE
   MONITORED FOR POTENTIAL WATCH ISSUANCE ACROSS PARTS OF THE AREA.

   DISCUSSION...19Z SFC OBSERVATIONS ILLUSTRATE A CORRIDOR OF ENHANCED
   CONVERGENCE ACROSS E-CNTRL IND...WHERE OUTFLOW FROM AN OVERNIGHT MCS
   INTERSECTS AN EWD-PROGRESSING COLD FRONT. IN RESPONSE...A BROKEN
   LINE OF CONVECTION HAS DEVELOPED THIS AFTERNOON...AIDED BY SOME
   FORCING FOR ASCENT FROM A SUBTLE IMPULSE ALOFT PROGRESSING E/SEWD
   ACROSS IL. ADDITIONALLY...MODEST SFC CONVERGENCE EXTENDING TO THE
   EAST MAY FAVOR FURTHER INITIATION ACROSS PORTIONS OF CNTRL OH OVER
   THE NEXT FEW HOURS. HOWEVER...HI-RES GUIDANCE OFFERS CONSIDERABLE
   DIFFERENCES REGARDING CONVECTIVE EVOLUTION...LENDING SOME
   UNCERTAINTY REGARDING THE SPATIAL EXTENT OF THE SEVERE THREAT THIS
   AFTERNOON.

   MORNING RAOBS SUGGEST MID-LEVEL LAPSE RATES ON THE ORDER OF 7 C/KM
   EXIST OVER PORTIONS OF THE REGION...WHICH IN COMBINATION WITH AMPLE
   DIURNAL HEATING AND SFC DEW POINTS IN THE MID/UPPER 60S TO NEAR
   70...HAS YIELDED MLCAPE VALUES AROUND 1500-2000 J/KG. REGIONAL VWP
   DATA EXHIBIT ENHANCED LOW/MID-LEVEL FLOW /E.G. 40 KTS AT 3 KM FROM
   KILN/. THUS...ANY STRONGER CONVECTION WILL BE CAPABLE OF DAMAGING
   WIND GUSTS...CONSIDERING THE WELL-MIXED BL. MOREOVER...EFFECTIVE
   SHEAR OF 35-40 KTS SHOULD AID UPDRAFT ORGANIZATION SUFFICIENTLY FOR
   AT LEAST MARGINALLY SEVERE HAIL IN CELLS THAT REMAIN DISCRETE.
   TRENDS WILL BE MONITORED FOR POSSIBLE WATCH ISSUANCE ACROSS PARTS OF
   THE AREA THIS AFTERNOON.

   ..PICCA/HART.. 08/03/2015


   ATTN...WFO...PBZ...RLX...CLE...ILN...LMK...IWX...IND...

   LAT...LON   40188567 40558527 40818347 40748124 40688091 39598113
               38728222 38488284 38598405 38748495 39368587 40188567