870
ACUS11 KWNS 201752
SWOMCD
SPC MCD 201752
RIZ000-CTZ000-NYZ000-NJZ000-PAZ000-DEZ000-201845-
MESOSCALE DISCUSSION 0804
NWS STORM PREDICTION CENTER NORMAN OK
1252 PM CDT WED MAY 20 2026
AREAS AFFECTED...PORTIONS OF THE MID-ATLANTIC INTO SOUTHERN NEW
ENGLAND
CONCERNING...SEVERE POTENTIAL...SEVERE THUNDERSTORM WATCH LIKELY
VALID 201752Z - 201845Z
PROBABILITY OF WATCH ISSUANCE...80 PERCENT
SUMMARY...WIDELY SCATTERED THUNDERSTORMS WILL BRING A RISK FOR
DAMAGING WIND GUSTS AND ISOLATED LARGE HAIL THROUGH THIS EVENING. A
SEVERE THUNDERSTORM WATCH WILL BE NEEDED SOON.
DISCUSSION...LATEST SURFACE OBSERVATIONS INDICATE THAT SURFACE
TEMPERATURES HAVE WARMED INTO THE LOW 90S F ACROSS PORTION OF THE
MID-ATLANTIC. COUPLED WITH MID-60S F DEWPOINTS, THIS IS SUPPORTING
500-1000+ J/KG MLCAPE ACROSS THE AREA, WITH FURTHER DESTABILIZATION
EXPECTED THROUGH PEAK HEATING THIS AFTERNOON. EXPECTATION IS FOR
ONGOING THUNDERSTORM ACTIVITY ACROSS SEVERE THUNDERSTORM WATCH 234
TO EXPAND EASTWARD, WITH ADDITIONAL DEVELOPMENT ALSO POSSIBLE ALONG
AN APPROACHING COLD FRONT. 20-30 KTS OF EFFECTIVE SHEAR WILL SUPPORT
MULTICELLS, AND PERHAPS MARGINAL SUPERCELLS. STEEP LOW-LEVEL LAPSE
RATES (8+ C/KM PER LATEST OBJECTIVE ANALYSIS) AND DEWPOINT
DEPRESSIONS OF 20-25+ F WILL PROMOTE THE POTENTIAL FOR DAMAGING WIND
GUSTS, ESPECIALLY WITH ANY MORE WELL-ORGANIZED CLUSTERS THAT
DEVELOP. ISOLATED LARGE HAIL MAY ALSO ACCOMPANY THE MOST ROBUST
UPDRAFTS. A NEW SEVERE THUNDERSTORM WATCH WILL BE NEEDED SOON.
..CHALMERS/HART.. 05/20/2026
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...BOX...OKX...ALY...PHI...BGM...
LAT...LON 40567574 40837554 41157502 41447382 41547334 41607289
41607231 41517205 41297181 41077177 40877191 40667263
40517332 40347368 39997393 39627403 39217449 39127488
39147530 39327557 39787578 40567574
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN
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