Mesoscale Discussion 0394
   NWS Storm Prediction Center Norman OK
   0555 PM CDT Fri Apr 17 2020

   Areas affected...central Pennsylvania into the Finger Lakes and
   Catskills of New York

   Concerning...Heavy snow 

   Valid 172255Z - 180300Z

   SUMMARY...Heavy snow is possible across portions of central
   Pennsylvania into the Finger Lakes and Catskills this
   evening/tonight. Snowfall rates of 1 inch per hour are likely.

   DISCUSSION...A positively-tilted upper-level shortwave trough is
   tracking east-southeast across the Great Lakes with weak, relative
   vorticity maxima spreading eastward downstream over Pennsylvania and
   the Northeast. A dual surface low structure has developed with one
   low in central Ohio and the other in far eastern Kentucky. An
   attendant warm front is draped east-west from central Ohio through
   central Pennsylvania with an area below freezing across southern New
   York/northern Pennsylania. Low-level warm-air advection and
   frontogenesis within 900-700 mb are resulting in precipitation
   across the region. Model soundings indicate marginal instability
   within the dendritic growth zone with upward motion values mostly
   supporting 0.5 to 1 inch per hour snowfall rates. However, upslope
   enhancement will aid snowfall rates across parts of the area. A
   downstream heavy snow MD may also be needed later this evening for
   portions of New York into central/southern New England.

   ..Nauslar/Goss.. 04/17/2020

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

   ATTN...WFO...ALY...BGM...BUF...CTP...PBZ...

   LAT...LON   42117859 41627899 41227892 40837835 40887756 41167679
               41437583 41537536 41617491 41717457 42077415 42767426
               42937497 42917597 42647767 42117859