Mesoscale Discussion 0597
   NWS Storm Prediction Center Norman OK
   1252 PM CDT Fri May 15 2020

   Areas affected...Parts of central Ohio into western New York and
   northwest Pennsylvania

   Concerning...Severe potential...Watch possible 

   Valid 151752Z - 151915Z

   Probability of Watch Issuance...60 percent

   SUMMARY...An increase in convective coverage and intensity are
   expected over the next few hours. Damaging gusts and occasional
   large hail will be the primary hazards with the strongest storms. A
   Severe Thunderstorm Watch issuance is possible in the next hour or
   so.

   DISCUSSION...A surface low and associated mid-level vort max,
   currently located over southern Ontario, are progressing eastward,
   resulting in recent convective initiation across far northeast OH
   into northwest PA. As a cold front exiting the Great Lakes area
   approaches, with upper-level support for ascent glancing the
   northeast through early afternoon, storm coverage will continue to
   increase. While buoyancy is currently quite modest, additional
   surface heating will help boost MLCAPE up to 1000 J/kg amidst 30-35
   knots of effective bulk shear, suggesting that organized convective
   structures will likely materialize through the afternoon hours.

   Modest mid-level lapse rates (6.4 C/km), and deep-layer shear
   vectors oriented roughly parallel to the cold front suggest that
   damaging gusts from water-loaded downdrafts embedded within linear
   segments will be the main severe threat. Occasional severe hail will
   also by possible with the strongest storm cores. The greatest threat
   will likely occur during the afternoon hours, until the cold front
   sweeps through by early evening. A Severe Thunderstorm Watch
   issuance may be needed in the next hour or two.

   ..Squitieri/Dial.. 05/15/2020

   ...Please see www.spc.noaa.gov for graphic product...

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

   LAT...LON   43137762 43097720 42727707 41947721 41397750 41047863
               40748008 40628178 40648276 40768314 41318203 42437942
               42867859 43137762