Mesoscale Discussion 0757
   NWS Storm Prediction Center Norman OK
   0947 AM CDT Fri May 29 2020

   Areas affected...Parts of the lower Great Lakes and Allegheny
   Plateau region

   Concerning...Severe potential...Watch possible 

   Valid 291447Z - 291645Z

   Probability of Watch Issuance...60 percent

   SUMMARY...Thunderstorms may begin to increase in coverage and
   intensity as early as Noon to 2 PM EDT, and will gradually pose
   increasing risk for small hail and strong surface gusts through the
   afternoon.  Trends are being monitored for the possibility of one or
   more severe weather watches this afternoon.

   DISCUSSION...Scattered areas of mostly weak convective development
   are underway.  This is occurring in the presence of moderate to
   strong deep-layer shear, beneath a belt of 40-50 kt southwesterly
   500 mb flow.  However, boundary-layer instability is still rather
   modest with CAPE on only the order of 500 J/kg, and mid-level flow
   remains broadly anticyclonic across much of the region.

   With the approach of one short wave trough turning eastward across
   the Great Lakes, and another accelerating north-northeastward out of
   the middle Ohio Valley ahead of it, mid-level flow appears likely to
   trend increasingly cyclonic through 16-18Z. Coupled with further
   boundary-layer destabilization in association with continuing
   insolation, the environment may become increasingly conducive to
   organized vigorous thunderstorm development.  

   Thunderstorm intensification probably will be gradual, but strongest
   storms may become capable of producing small to marginally severe
   hail and potentially damaging wind gusts through the afternoon.

   ..Kerr/Grams.. 05/29/2020

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

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

   LAT...LON   43757523 42417479 41697736 40337961 39618212 40628294
               43117840 43757523