Mesoscale Discussion 1744
   NWS Storm Prediction Center Norman OK
   1215 PM CDT Thu Aug 15 2019

   Areas affected...Portions of eastern OH...western/central PA...far
   southern NY...western MD...northern/eastern WV...and
   northern/central VA

   Concerning...Severe potential...Watch possible 

   Valid 151715Z - 151915Z

   Probability of Watch Issuance...40 percent

   SUMMARY...The threat for large hail and damaging winds with
   scattered storms should continue to increase this afternoon. Watch
   issuance is possible, with a relatively greater chance from eastern
   Ohio into Pennsylvania.

   DISCUSSION...Convection will likely continue to increase in coverage
   and intensity this afternoon across eastern OH into parts of the
   Mid-Atlantic as a weak shortwave trough moves eastward across the
   Great Lakes and OH Valley through this evening. Low-level flow over
   these regions remains generally weak, but west-southwesterly winds
   do strengthen through mid levels. Resultant 35-45 kt of effective
   bulk shear will likely promote discrete storm modes, with some
   supercell structures possible. A moist low-level airmass is also
   present across these areas per 12Z soundings and latest surface
   observations. Additional diurnal heating through the remainder of
   the afternoon will contribute to moderate instability, with MLCAPE
   of 1500-2000 J/kg expected.

   Somewhat greater storm coverage may be realized across eastern OH
   into western/central PA and vicinity, which will be closer to the
   modest large-scale ascent associated with the approaching shortwave
   trough. Farther south into western MD and northern/central VA, weak
   low-level easterly upslope flow has encouraged isolated storms
   along/east of the Blue Ridge Mountains. A similar instability/shear
   parameter space will exist across both regions, with isolated large
   hail and damaging wind gusts possible. Additional storms may form
   along a lake breeze in northeastern OH/northwestern PA, and along a
   weak surface trough in eastern OH. Observational trends will
   continue to be closely monitored for possible watch issuance this
   afternoon. Severe Thunderstorm Watch potential seems relatively
   greater across parts of eastern OH into PA and vicinity based on
   latest short-term model trends.

   ..Gleason/Grams.. 08/15/2019

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

   ATTN...WFO...BGM...AKQ...BUF...CTP...LWX...RNK...PBZ...CLE...

   LAT...LON   41687628 41397619 41007628 38967718 37997749 37377785
               37257844 37447893 37937909 38877903 39467940 39848020
               40548141 41058213 41258209 41508131 42068004 42297882
               42287759 42027675 41687628