Storm Prediction Center Mesoscale Discussion 97

   Mesoscale Discussion 0097
   NWS Storm Prediction Center Norman OK
   1150 AM CST Sat Feb 15 2025

   Areas affected...parts of southern Pennsylvania and northwest
   Maryland

   Concerning...Freezing rain 

   Valid 151750Z - 152145Z

   SUMMARY...Freezing rain is expected with ice accretion of 0.05" to
   0.1" is possible this afternoon across parts of south-central
   Pennsylvania and adjacent areas of Maryland.

   DISCUSSION...A broad area of low-level warm advection across the
   mid-Atlantic states is providing the lift for widespread
   precipitation occurring across the region. The transition zone from
   snow across the northern parts of the region to rain across the
   southern parts is currently across southwestern Pennsylvania into
   northeastern West Virginia, which should generally lift
   northeastward with time. The advance of the warmer mid-level air is
   apparent on KCCX radar with lowered correlation coefficient
   indicating melting of hydrometeors. However, the surface cold air
   has been slow to erode, with parts of south-central Pennsylvania and
   adjacent areas of Maryland remaining below freezing at the surface.
   A couple surface sites across south-central Pennsylvania and
   adjacent areas of West Virginia and Maryland are reporting unknown
   precip with temperatures below freezing, likely indicating a
   transition to freezing rain has begin. 

   NAM forecast profiles this afternoon across parts of the region show
   classic freezing rain conditions, with a shallow layer of
   below-freezing air with a large warm nose aloft. One potential
   mitigating factor for ice accretion is that surface wet-bulb
   temperatures generally hover in the 30-32 F range, which is marginal
   for significant ice accretion. With time, expect the low-level cold
   air to erode and transition to all rain later this afternoon as the
   precipitation ends from west to east.

   ..Supinie.. 02/15/2025

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

   ATTN...WFO...CTP...LWX...PBZ...

   LAT...LON   39907979 40427946 40617901 40827861 40917805 40837758
               40607696 40177676 39837700 39677752 39617790 39597834
               39587885 39607951 39727974 39907979