Mesoscale Discussion 0493
NWS Storm Prediction Center Norman OK
0943 PM CDT Sat Apr 19 2025
Areas affected...portions of southeast Pennsylvania and northeast
Maryland
Concerning...Severe potential...Watch unlikely
Valid 200243Z - 200415Z
Probability of Watch Issuance...20 percent
SUMMARY...Strong to severe gusts will accompany an eastward moving
MCS over the next few hours.
DISCUSSION...A rapidly eastward propagating, likely cold-pool-driven
MCS, with a history of measured severe/damaging gusts (some
exceeding 65 kts), persists along the PA/MD border. The 00Z observed
IAD sounding depicts a relatively dry boundary layer in the general
area, suggesting that deep-layer evaporative cooling is contributing
to a deep/strong cold pool, which is likely supporting both MCS
longevity, and severity of the corresponding severe wind swath.
However, decreasing lightning trends raises questions as to how long
this MCS will persist given weak to modest synoptic forcing, with
longevity dependent on cold pool maintenance. Nonetheless, as long
as the MCS persists, strong to potentially severe gusts remain
possible.
..Squitieri.. 04/20/2025
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...PHI...CTP...LWX...
LAT...LON 39447672 39537694 39727698 39947678 39947665 39987619
39837556 39587542 39377562 39337612 39447672
MOST PROBABLE PEAK WIND GUST...65-80 MPH
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