MESOSCALE DISCUSSION 1187
   NWS STORM PREDICTION CENTER NORMAN OK
   0831 PM CDT WED JUN 17 2009
   
   AREAS AFFECTED...PARTS OF FAR ERN OH / NRN WV / SWRN PA / MD
   PANHANDLE
   
   CONCERNING...TORNADO WATCH 442...
   
   VALID 180131Z - 180230Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 442 CONTINUES.
   
   SEVERE POTENTIAL WILL LIKELY PERSIST BEYOND WW 442 EXPIRATION AT 02Z
   ACROSS FAR ERN OH / NRN WV / SWRN PA / MD PANHANDLE.  A REPLACEMENT
   WW WILL PROBABLY BE ISSUED SOON.
   
   01Z SURFACE ANALYSIS SHOWS RESIDUAL BAROCLINIC ZONE /REINFORCED BY
   CLOUDS-PRECIP/ ACROSS SWRN PA BEFORE BECOMING MORE DIFFUSE SWD INTO
   ERN WV.  A COLD FRONT IS BEGINNING TO SLIDE ESEWD INTO E-CNTRL OH IN
   RESPONSE TO EWD DEPARTING SHORTWAVE TROUGH INTO PARTS OF WRN NY. 
   LATEST RADAR MOSAIC SHOWS SEVERAL SEVERE CLUSTERS...INCLUDING
   SUPERCELLS/ ACROSS THE UPPER OH RIVER VALLEY.  
   
   DESPITE LOSS OF DAYTIME HEATING...MORE THAN ADEQUATE SHEAR/POTENTIAL
   INSTABILITY IN ADDITION TO FORCING FOR ASCENT...WILL LIKELY MAINTAIN
   SEVERE POTENTIAL FOR THE NEXT FEW HOURS.  WHILE AN ISOLD TORNADO IS
   STILL POSSIBLE IN THE NEXT HOUR OR TWO...IT APPEARS THIS THREAT MAY
   BE WANING DUE TO 1)GRADUAL CONSOLIDATION OF DISCRETE ELEMENTS INTO
   BROKEN CLUSTERS/LINES 2)INCREASING SBCIN DUE IN PART TO MODEST
   DIURNAL STABILIZATION.  NONETHELESS...STORMS WILL LIKELY POSE A
   CONTINUED LARGE HAIL/DMGG WIND THREAT...PERHAPS EVOLVING MORE INTO A
   DMGG WIND THREAT WITH TIME.
   
   ..SMITH.. 06/18/2009
   
   
   ATTN...WFO...CTP...LWX...PBZ...RLX...CLE...
   
   LAT...LON   38927985 39698137 40068193 40258192 40448166 40458090
               40448081 40297932 39917846 39507842 39117909 38927985