MESOSCALE DISCUSSION 0407
   NWS STORM PREDICTION CENTER NORMAN OK
   0237 AM CDT MON APR 06 2009
   
   AREAS AFFECTED...SC...SRN NC
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 060737Z - 060900Z
   
   THE SEVERE THREAT SHOULD INCREASE ACROSS SC INTO SRN NC LATE
   TONIGHT. LARGE HAIL AND ISOLATED DAMAGING WIND GUSTS WILL BECOME
   INCREASINGLY LIKELY AS STORMS EXPAND IN COVERAGE OVER THE NEXT 2 TO
   4 HOURS. ALTHOUGH THE THREAT WILL INITIALLY BE MARGINAL...A MORE
   SUBSTANTIAL SEVERE THREAT SHOULD DEVELOP BY DAYBREAK. A WW MAY BE
   NEEDED ACROSS THE REGION WITH THE MOST LIKELY TIMEFRAME OF ISSUANCE
   FROM 09Z TO 11Z.
   
   07Z SFC ANALYSIS SHOWS A SFC LOW IN ERN OH WITH A COLD FRONT
   EXTENDING SSWWD INTO ERN TN AND ERN AL. AHEAD OF THE FRONT...A
   PRE-FRONTAL TROUGH IS LOCATED IN THE SRN APPALACHIAN MTNS. A CLUSTER
   OF STORMS IS DEVELOPING AHEAD OF THE SFC TROUGH AND NEAR A VORTICITY
   MAXIMUM ACCORDING TO THE RUC. THIS ACTIVITY IS ALONG AN EAST TO WEST
   MOISTURE GRADIENT WITH LOWER TO MID 60S F DEWPOINTS FEEDING THE
   CONVECTION FROM THE SOUTH. ALTHOUGH INSTABILITY IS RELATIVELY
   WEAK...MLCAPE VALUES SHOULD INCREASE TO AROUND 1000 J/KG ACROSS THE
   MCD AREA AS MOISTURE ADVECTION CONTINUES LATE TONIGHT. CONCERNING
   THE SHEAR ENVIRONMENT...THE CHARLESTON SC WSR-88 VWP SHOWS ABOUT 70
   KT OF 0-6 KM SHEAR WITH 0-3 KM SRH VALUES AROUND 350 M2/S2. THIS
   SHOULD BE SUPPORTIVE OF SUPERCELLS WITH FORECAST SOUNDINGS
   SUGGESTING THE STORMS WILL REMAIN ELEVATED FOR A FEW MORE HOURS WITH
   HAIL THE MAIN THREAT. AS MOISTURE INCREASES...THE MODELS SUGGEST
   SFC-BASED STORMS WILL BECOME MORE LIKELY WITH TIME. THIS SHOULD
   RESULT IN A WIND DAMAGE THREAT. AN ISOLATED TORNADO THREAT MAY ALSO
   DEVELOP IF ANY SUPERCELLS CAN ORGANIZE AND BECOME PERSISTENT.
   
   ..BROYLES.. 04/06/2009
   
   
   ATTN...WFO...MHX...RAH...ILM...CHS...CAE...GSP...
   
   LAT...LON   33317928 33368016 33458122 33858185 34198198 34598153
               35397971 35557886 35547768 35057718 34397759 34017799
               33737878 33317928