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Mesoscale Discussion 1139
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MD 1139 graphic

   Mesoscale Discussion 1139
   NWS Storm Prediction Center Norman OK
   0353 PM CDT Fri Jun 23 2017

   Areas affected...Northern KY...Southern OH...Northern WV...Western
   MD...Southern PA

   Concerning...Severe Thunderstorm Watch 366...

   Valid 232053Z - 232300Z

   The severe weather threat for Severe Thunderstorm Watch 366

   SUMMARY...The threat for damaging winds and perhaps a brief tornado

   DISCUSSION...Several clusters of thunderstorms are ongoing across
   the valid portion of WW 366, with a tendency for convection to
   evolve into short line segments. This mode is generally expected to
   continue, given unidirectional southwesterly wind profiles across
   the region. Periodic damaging wind gusts will be possible with these
   line segments, while a brief tornado also cannot be ruled out, given
   relatively strong 0-1 km shear of 20-30 kts noted in VWPs from CCX
   and PBZ. A somewhat greater conditional threat of a tornado or two
   would exist with any discrete cells that can be maintained, though
   thus far convection has rather quickly evolved into line segments as
   storms intensify.

   A cluster of storms moving into southeast PA will begin to move out
   of WW 366 within the hour, posing some severe threat into at least 
   southeast PA. Please refer to MCD 1135 for additional details
   regarding the severe threat downstream of WW 366.

   ..Dean.. 06/23/2017

   ...Please see for graphic product...


   LAT...LON   38768446 39388245 39967991 40477789 40597644 40287580
               39687638 39607762 39317904 38938129 38478294 38328439
               38378442 38768446 

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