MESOSCALE DISCUSSION 0437
   NWS STORM PREDICTION CENTER NORMAN OK
   1011 PM CDT WED APR 10 2013
   
   AREAS AFFECTED...PORTIONS SRN PA...NRN MD...NRN DE...ERN PANHANDLE
   OF WV.
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 91...
   
   VALID 110311Z - 110445Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 91
   CONTINUES.
   
   SUMMARY...REMAINDER WW MAY BE CLEARED BEHIND BAND OF TSTMS NOW
   MOVING ESEWD ACROSS MTNS OF S-CENTRAL PA.  PRIND ACTIVITY WILL
   CONTINUE WEAKENING TREND...AND NO FURTHER WWS WILL BE REQUIRED FOR
   THIS AREA TONIGHT.
   
   DISCUSSION...MCS THAT EARLIER PRODUCED SVR WIND MEASUREMENTS AND
   SOME WIND-DAMAGE REPORTS OVER PORTIONS S-CENTRAL/SERN PA HAS
   WEAKENED CONSIDERABLY WHILE MOVING INTO NJ...UPON ENCOUNTERING
   COMBINATION OF RELATIVELY COLD/STABLE MARINE LAYER AND OUTFLOW FROM
   EARLIER TSTMS.  THAT ACTIVITY...IN TURN...HAS LEFT OUTFLOW BOUNDARY
   ACROSS NRN PORTIONS DE/MD...WNWWD BETWEEN HGR-MRB...INTERSECTING
   OUTFLOW FROM ONGOING SRN PA TSTM BAND INVOF CBE.  LATTER ACTIVITY
   WILL REMAIN N OF OUTFLOW BOUNDARY...WHILE MOVING INTO RELATIVELY
   STABLE/LOW-THETAE AIR MASS CHARACTERIZING S-CENTRAL/SERN PA.  WHILE
   A FEW STG TO MRGLLY DAMAGING GUSTS STILL ARE POSSIBLE...PRIND
   LOW-LEVEL INSTABILITY WILL CONTINUE TO DIMINISH ACROSS MOST OF
   DISCUSSION AREA FROM COMBINATION OF DIABATIC SFC COOLING AND OUTFLOW
   AIR.  NEARLY SFC-BASED CONVECTION STILL IS POSSIBLE VERY NEAR
   OUTFLOW BOUNDARY ACROSS PORTIONS NRN MD AND DE...HOWEVER SVR THREAT
   APPEARS TOO DISORGANIZED/MRGL FOR ADDITIONAL WW...GIVEN LIKELIHOOD
   OF INCREASING MLCINH...AND MLCAPE ALREADY LESS THAN 500 J/KG AND
   DECREASING.
   
   ..EDWARDS.. 04/11/2013
   
   
   ATTN...WFO...PHI...CTP...LWX...
   
   LAT...LON   39747869 40227823 40677794 40497670 39907562 39657552
               39297575 39447796 39747869