592 

ACUS11 KWNS 201623

SWOMCD

SPC MCD 201623 

PAZ000-DEZ000-MDZ000-DCZ000-VAZ000-WVZ000-201800-



Mesoscale Discussion 0801

NWS Storm Prediction Center Norman OK

1123 AM CDT Wed May 20 2026



Areas affected...portions of the Mid-Atlantic



Concerning...Severe potential...Severe Thunderstorm Watch likely 



Valid 201623Z - 201800Z



Probability of Watch Issuance...80 percent



SUMMARY...Widely scattered thunderstorms will pose a risk for

damaging wind gusts and isolated large hail this afternoon and

evening. A Severe Thunderstorm Watch will be needed soon.



DISCUSSION...Latest surface observations depict a cold front

extending from central New York southwestward through north-central

and western Pennsylvania into southeast Ohio. Ahead of this cold

front, temperatures are warming into the 90s across portions of the

Mid-Atlantic, with surface dewpoints in the low/mid 60s F. Continued

heating of this air mass is supporting 1000-1500 J/kg MLCAPE, with

further destabilization anticipated through the afternoon hours.



Recent satellite/radar imagery has shown increasing convective

coverage ahead of the aforementioned cold front as remaining

inhibition is eroded. With stronger mid/upper-level flow remaining

displaced to the northwest, only modest effective shear is analyzed

across the region (generally 20-30+ kts per latest mesoanalysis).

This will be sufficient to support updraft organization with

multicells, and perhaps marginal supercells, likely. Steep low-level

lapse rates, well-mixed boundary layer profiles, and surface

dewpoint depressions exceeding 20-25 F will promote the potential

for damaging wind gusts, particularly with any more organized

clusters that develop. Isolated instances of large hail may also

accompany any more robust updrafts despite weak mid-level lapse

rates (as sampled by the 12z PIT/IAD observed soundings). A Severe

Thunderstorm Watch will be needed soon.



..Chalmers/Hart.. 05/20/2026



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



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



LAT...LON   40687798 40987676 40987614 40907587 40747568 40397553

            39967560 39437589 39147621 38927665 38687793 38597862

            38587907 38767959 39117993 39388003 39737992 40107959

            40247926 40687798 



MOST PROBABLE PEAK WIND GUST...55-70 MPH

MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN