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Mesoscale Discussion 1330
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MD 1330 graphic

   Mesoscale Discussion 1330
   NWS Storm Prediction Center Norman OK
   0237 PM CDT Mon Jul 17 2017

   Areas affected...Far northeastern Pennsylvania...central/eastern New
   York...and much of Vermont

   Concerning...Severe Thunderstorm Watch 417...

   Valid 171937Z - 172030Z

   The severe weather threat for Severe Thunderstorm Watch 417

   SUMMARY...The severe threat continues across much of WW 417.

   DISCUSSION...Storms have increased as anticipated - and congealed
   into several forward-propagating linear segments with a history of
   isolated hail and a few wind gusts.  The airmass ahead of storms is
   characterized by weak to moderate instability (around 1000 J/kg
   MUCAPE in Vermont increasing to 3000 J/kg in eastern Pennsylvania)
   along with marginal, but sufficient, deep shear for organized
   convection. Storms will generally migrate east/northeastward for the
   remainder of the afternoon and continue to pose at least an isolated
   damaging wind/hail threat.  Storms should weaken after dark with the
   onset of nocturnal boundary-layer cooling.

   Areas on the northern and western peripheries of WW 417 have
   experienced substantial overturning from ongoing convection.  Weaker
   storms are present in these areas that may pose a threat for small
   hail, although the bulk of the severe threat should reside with more
   unstable low-level conditions downstream.

   ..Cook.. 07/17/2017

   ...Please see for graphic product...


   LAT...LON   43087652 43487591 44047495 44557356 44977264 45037177
               44797151 44137211 43307238 42767289 42227391 41687477
               41217548 41027591 41097655 41437706 41807735 42487699

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