Mesoscale Discussion 0149
   NWS Storm Prediction Center Norman OK
   0933 PM CST Fri Feb 16 2024

   Areas affected...Northeast West Virginia to western New Jersey

   Concerning...Heavy snow 

   Valid 170333Z - 170730Z

   SUMMARY...A swath of moderate to heavy snowfall will continue to
   spread east across parts of the Mid-Atlantic over the next several
   hours.

   DISCUSSION...A swath of moderate snowfall continues to spread east
   from the upper OH River Valley region into the Mid-Atlantic based on
   recent regional reflectivity composites. Transient organized snow
   bands continue to be observed within this broader zone, resulting in
   visibility reductions from 1/2 to 1/4 mile and steady snowfall
   accumulations based on recent snow reports from the region.
   Favorable phasing of synoptic ascent ahead of the approaching
   shortwave trough and strong isentropic and frontogenetic lift within
   the 925-700 mb layer, which has been driving this activity so far,
   is expected to persist as the system pushes towards the East Coast
   over the next several hours. Latest forecast guidance depicts
   reasonably high probability in snowfall rates between 1-2 inch/hour
   across portions of the Mid-Atlantic region (and possibly as far east
   as the NJ coast) through 08 UTC. Based on observed trends, this
   depiction seems fairly reasonable. One caveat is a lingering
   warm/dry layer below 850 mb sampled by regional 00 UTC soundings and
   noted in surface observations across northern MD, southeast PA, and
   into western NJ, which may limit snowfall rates in the near term.
   However, a combination of evaporative cooling and persistent
   mesoscale ascent along the warm frontal zone should support adequate
   low-level saturation/cooling to allow for moderate to heavy snowfall
   in the coming hours.

   ..Moore.. 02/17/2024

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

   ATTN...WFO...PHI...BGM...CTP...LWX...PBZ...RLX...

   LAT...LON   39027964 39317946 40797816 40987781 41047727 41097559
               41007515 40867482 40557450 40117448 39847474 39707510
               39607581 39587636 39537690 39397762 39217805 38927844
               38757868 38677897 38687925 38787956 39027964