MESOSCALE DISCUSSION 1160
   NWS STORM PREDICTION CENTER NORMAN OK
   0517 PM CDT THU JUN 09 2011
   
   AREAS AFFECTED...S-CNTRL PA...CNTRL/ERN WV...NRN VA...WASHINGTON
   DC...MD
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 451...
   
   VALID 092217Z - 092315Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 451
   CONTINUES.
   
   THE POTENTIAL FOR SVR THUNDERSTORMS WILL CONTINUE ACROSS PRIMARILY
   NRN AND ERN PORTIONS OF THE WW AREA. ISOLATED THUNDERSTORMS HAVE
   DEVELOPED OVER NWRN VA...AND MAY APPROACH THE WASHINGTON DC METRO
   AREA AFTER 23Z WITH THE POTENTIAL FOR DMGG WIND GUSTS AND LARGE
   HAIL. 
   
   LATEST SFC ANALYSIS PLACES A COLD FRONT FROM IPT TO 15 NNE MGW TO 25
   SSW ZZV....WITH A PREFRONTAL CONFLUENCE ZONE /NOTED BY WLY WIND
   SHIFT IN ITS WAKE/ POSITIONED OVER NWRN VA. ISOLATED THUNDERSTORMS
   HAVE FORMED ALONG THIS CONFLUENCE ZONE...WHICH IS LOCATED WITHIN A
   VERY HOT BOUNDARY LAYER /CHARACTERIZED BY SFC TEMPERATURES IN THE
   MID-UPPER 90S/. THE STRONGEST MIDLEVEL FLOW REMAINS POSITIONED
   ACROSS NRN PORTIONS OF THE WW /PRIMARILY SRN PA/ AND WILL YIELD
   EFFECTIVE SHEAR SUPPORTIVE OF MARGINALLY ORGANIZED STORM STRUCTURES.
   FARTHER S...MIDLEVEL FLOW DECREASES RAPIDLY AND SHOULD TEND TO LIMIT
   STORM ORGANIZATION...THOUGH MODEST LOW-LEVEL FORCING ALONG THE
   CONFLUENCE ZONE AND A VERY UNSTABLE ENVIRONMENT WILL SUPPORT SMALL
   MULTICELL CLUSTERS. REGARDLESS...THE POTENTIAL FOR DMGG WIND GUSTS
   /OWING TO STEEP LOW-LEVEL LAPSE RATES/ AND LARGE HAIL /WITH MLCAPE
   VALUES RANGING FROM 2000-3000 J/KG/ WILL CONTINUE FROM SRN PA INTO
   NRN VA.
   
   ..ROGERS.. 06/09/2011
   
   
   ATTN...WFO...AKQ...CTP...LWX...RNK...PBZ...RLX...
   
   LAT...LON   37548163 38368212 39208045 39938011 40797858 40837728
               39997659 39187644 38777679 38247735 38117838 37857915
               37548163