MESOSCALE DISCUSSION 1873
   NWS STORM PREDICTION CENTER NORMAN OK
   0147 PM CDT WED SEP 11 2013

   AREAS AFFECTED...ERN OH...WRN/NRN PA...WRN NY

   CONCERNING...SEVERE THUNDERSTORM WATCH 520...

   VALID 111847Z - 111945Z

   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 520
   CONTINUES.

   SUMMARY...SEVERE THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA.

   DISCUSSION...NUMEROUS THUNDERSTORMS HAVE DEVELOPED ACROSS PORTIONS
   OF THE UPPER OH VALLEY INTO SRN NY.  MANY STORMS HAVE TAKEN ON
   CHARACTERISTICS THAT APPEAR FAVORABLE FOR WET MICROBURSTS AND LARGE
   HAIL...PER LATEST WDSSII ALGORITHM. THIS ACTIVITY HAS EVOLVED WITHIN
   A MODERATELY UNSTABLE AIRMASS THAT REMAINS SUPPORTIVE OF ROBUST
   MULTICELL UPDRAFTS AND A GRADUAL NEWD EXPANSION IS EXPECTED ACROSS
   NY TOWARD THE HUDSON VALLEY OVER THE NEXT FEW HOURS.  UNTIL
   SIGNIFICANT CONVECTIVE OVERTURNING HAS OCCURRED SEVERE STORMS ARE
   EXPECTED ACROSS WW520.

   ..DARROW.. 09/11/2013


   ATTN...WFO...ALY...BGM...BUF...CTP...PBZ...RLX...CLE...

   LAT...LON   41718189 43837512 41517512 39398189 41718189