MESOSCALE DISCUSSION 1440
   NWS STORM PREDICTION CENTER NORMAN OK
   0829 PM CDT FRI JUL 19 2013

   AREAS AFFECTED...WRN THROUGH CNTRL AND ECNTRL NY

   CONCERNING...SEVERE THUNDERSTORM WATCH 423...

   VALID 200129Z - 200300Z

   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 423
   CONTINUES.

   SUMMARY...THREAT FOR ISOLATED DAMAGING WIND WILL PERSIST NEXT 2-3
   HOURS OVER MUCH OF THE SRN HALF OF NY. SOME STORMS ARE APPROACHING
   THE SRN END OF WW 424...AND THE WW CAN BE LOCALLY EXTENDED IN AREA
   TO INCLUDE ANOTHER COUPLE ROWS OF COUNTIES. OTHER STORMS MAY POSE A
   DAMAGING WIND THREAT FOR NERN OH INTO NWRN PA NEXT COUPLE
   HOURS...BUT DURATION OF THIS THREAT IS NOT EXPECTED TO BE SUFFICIENT
   FOR A WW.

   DISCUSSION...STORMS HAVE UNDERGONE SOME INCREASE IN INTENSITY FROM
   WRN THROUGH ECNTRL NY...PRIMARILY WITHIN ZONE OF ENHANCED
   CONVERGENCE RESULTING FROM MERGING OF AN EXPANSIVE ESEWD ADVANCING
   OUTFLOW BOUNDARY WITH THE PRE-EXISTING LAKE BREEZE. THE 00Z RAOB
   FROM BUFFALO SHOWS WEAK VERTICAL SHEAR BUT 40-45 KT WLY WINDS
   BETWEEN 1 AND 8 KM. MUCH OF THE CONVECTIVE LINE SEGMENTS ARE
   PARALLEL TO THE DEEP LAYER WINDS WHICH IS A LIMITING FACTOR TO SOME
   DEGREE FOR A MORE ROBUST SEVERE WIND EVENT. NEVERTHELESS...SOME OF
   THE STRONGER STORMS WITHIN THE LINE WILL REMAIN CAPABLE OF ISOLATED
   DAMAGING WIND AS THEY DEVELOP ESEWD. LINE OF STORMS APPROACHING NRN
   LAKE ERIE IS ORIENTED NEARLY PERPENDICULAR TO THE MEAN FLOW AND
   APPEARS TO HAVE A BOWING STRUCTURE ON ITS NRN END. THIS ACTIVITY
   MIGHT POSE A SEVERE THREAT AS IT MOVES INTO WRN NY.
   HOWEVER...OUTFLOW FROM THE E-W BAND OF STORMS DOWNSTREAM IS SETTLING
   SWD AND SHOULD TEND TO UNDERCUT THIS LINE...SUGGESTING IT MIGHT
   WEAKEN AS IT MOVES BEYOND THE ERN SHORE OF LAKE ERIE.

   OTHER STORMS MOVING SEWD THROUGH CNTRL LAKE ERIE MAY POSE A RISK FOR
   ISOLATED DAMAGING WIND FROM NERN OH INTO NWRN PA. HOWEVER...THESE
   STORMS ARE MOVING SOUTH OF THE STRONGER WINDS ALOFT AND SHOULD BEGIN
   A WEAKENING TREND AFTER ANOTHER COUPLE HOURS AS THE BOUNDARY LAYER
   BEGINS TO COOL.

   ..DIAL.. 07/20/2013


   ATTN...WFO...ALY...BGM...BUF...

   LAT...LON   43127755 43317629 43727404 43327341 42597394 42397628
               42457864 42997858 43127755