MESOSCALE DISCUSSION 0264
   NWS STORM PREDICTION CENTER NORMAN OK
   0713 PM CDT WED MAR 23 2011
   
   AREAS AFFECTED...SRN PA...NE WV...NRN VA
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 57...
   
   VALID 240013Z - 240145Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 57
   CONTINUES.
   
   SEVERE THREAT CONTINUES ACROSS MAINLY SE THIRD OF SEVERE
   THUNDERSTORM WATCH 57. DOWNSTREAM OF WATCH...THREAT BECOMES MORE
   MARGINAL AND AN ADDITIONAL WW IS NOT ANTICIPATED. 
   
   INITIAL TSTM ACTIVITY HAS MOVED OUT OF THE WATCH AREA...WHILE A
   BROKEN LINE OF TSTMS HAS MOVED IN FROM THE WEST AND HAS CLEARED THE
   NW HALF OF THE WATCH. 23Z OBJECTIVE ANALYSIS INDICATES ONLY MARGINAL
   INSTABILITY /MU CAPE AOB 500 J/KG/ AHEAD OF THIS ACTIVITY.
   HOWEVER...30-40 KTS OF EFFECTIVE SHEAR BE SUFFICIENT TO SUPPORT SOME
   STORM ORGANIZATION...WITH STEEP MID-LEVEL LAPSE RATES CONTINUING TO
   SUPPORT A THREAT OF MARGINALLY SEVERE HAIL. A LACK OF SFC-BASED
   INSTABILITY WILL LIMIT THE OVERALL SEVERE WIND THREAT...WITH THE
   GREATEST THREAT ACROSS THE SERN THIRD OF THE WATCH WHERE SFC TEMPS
   ARE STILL CURRENTLY IN THE UPPER 50S/LOWER 60S. 
   
   DOWNSTREAM OF THE WATCH ACROSS SE PA...CNTRL MD...AND FAR NE
   VA...STEEP LAPSE RATES WILL SUPPORT A MARGINAL THREAT OF SEVERE
   HAIL...BUT THE OVERALL THREAT APPEARS TOO LOW FOR ANOTHER WW
   ISSUANCE.
   
   ..DEAN.. 03/24/2011
   
   
   ATTN...WFO...AKQ...LWX...
   
   LAT...LON   38437850 38667825 38897810 39107786 39297762 39427728
               39487697 39487687 39487674 39467646 39267635 39047640
               38627653 38287669 38127698 38067737 38057793 38007862
               38037892 38117908 38147902 38297883 38437850