MESOSCALE DISCUSSION 1087
   NWS STORM PREDICTION CENTER NORMAN OK
   0451 PM CDT SAT JUN 04 2011
   
   AREAS AFFECTED...ERN/CNTRL OH...FAR WRN PA...NWRN WV
   
   CONCERNING...SEVERE POTENTIAL...SEVERE THUNDERSTORM WATCH LIKELY 
   
   VALID 042151Z - 042215Z
   
   THE POTENTIAL FOR SVR STORMS IS INCREASING...AND THE ISSUANCE OF A
   SVR TSTM WATCH IS LIKELY SE OF WW426.
   
   DEEP CONVECTION CONTINUES TO INITIATE ALONG A LAKE BREEZE BOUNDARY
   EXTENDING FROM WEST OF THE YOUNGSTOWN AREA TOWARD MANSFIELD AND
   FARTHER WEST TOWARD LIMA AND INTO NRN IND. THE MOST VIGOROUS
   DEVELOPMENT HAS BEEN NOTED INVOF THE INTERSECTION OF THE LAKE BREEZE
   AND A WARM FRONT /AIDED BY CROSS-FRONTAL DIFFERENTIAL
   HEATING/...NEAR AND NORTHWEST OF CANTON OH. THE WARM FRONT WILL
   PROPAGATE EWD WITH TIME TOWARD THE OHIO RIVER...IN RESPONSE TO
   DIABATIC HEATING ASSOCIATED WITH INSOLATION EAST OF THE BOUNDARY
   WHERE 2-HR PRESSURE FALLS IN EXCESS OF 1.5 MB HAVE BEEN NOTED IN SFC
   OBS. THIS WILL ALLOW THE WARM SECTOR TO EXPAND EWD WITH TIME...IN
   WHICH A MODERATELY UNSTABLE AIR MASS EXISTS -- I.E. MLCAPE VALUES
   FROM 1500 TO 2500 J PER KG. DESPITE THE LACK OF STRONGER
   MID/UPPER-LEVEL FORCING...SUFFICIENT LOW-LEVEL CONVERGENCE EXISTS
   FOR SCATTERED TO NUMEROUS CONVECTIVE DEVELOPMENT. MERGING COLD POOLS
   COULD YIELD UPSCALE GROWTH INTO ONE OR MORE LINEAR CONVECTIVE
   SYSTEMS DIVING SSEWD...WITH SOME SWD PROPAGATION COMPONENT ALONG THE
   WARM FRONT. THIS WILL BE AIDED BY NWLY EFFECTIVE BULK SHEAR VECTORS
   WITH MAGNITUDES OF 35 TO 45 KT. DMGG WIND GUSTS WILL THE PRIMARY
   CONCERN WITH THIS ACTIVITY...ESPECIALLY WITH WELL-DEFINED BOWING
   LINE SEGMENTS...THOUGH A FEW INSTANCE OF LARGE HAIL WILL ALSO BE
   POSSIBLE WITH THE MORE VIGOROUS UPDRAFTS.
   
   ..COHEN.. 06/04/2011
   
   
   ATTN...WFO...PBZ...RLX...CLE...ILN...
   
   LAT...LON   40008318 40978300 41408244 41528118 41108035 39808038
               38718095 38378174 38558258 38948304 39338316 40008318