390
ACUS11 KWNS 202026
SWOMCD
SPC MCD 202026
NJZ000-PAZ000-DEZ000-MDZ000-202230-
MESOSCALE DISCUSSION 2054
NWS STORM PREDICTION CENTER NORMAN OK
0326 PM CDT THU AUG 20 2026
AREAS AFFECTED...PARTS OF SOUTHEASTERN PENNSYLVANIA...SOUTHERN NEW
JERSEY...EASTERN MARYLAND AND DELAWARE
CONCERNING...TORNADO WATCH 605...
VALID 202026Z - 202230Z
THE SEVERE WEATHER THREAT FOR TORNADO WATCH 605 CONTINUES.
SUMMARY...AN ORGANIZING CLUSTER OF STORMS WILL POSE INCREASING
POTENTIAL TO PRODUCE DAMAGING WIND GUSTS AND A COUPLE OF TORNADOES
INTO AND ACROSS THE GREATER PHILADELPHIA VICINITY THROUGH THE THE
6-7 PM EDT TIME FRAME.
DISCUSSION...A MORE PROMINENT, BUT STILL COMPACT, CLUSTERING OF
INTENSIFYING THUNDERSTORM DEVELOPMENT IS ONGOING SOUTH/SOUTHEAST OF
HARRISBURG PA. THIS DOES APPEAR FOCUSED NEAR A WEAK DEVELOPING
FRONTAL WAVE, AND IS PERHAPS BEING SUPPORTED BY FORCING FOR ASCENT
DOWNSTREAM OF AN EAST-NORTHEASTWARD PROPAGATING 50+ KT MID-LEVEL JET
STREAK, BASED ON THE LATEST RAPID REFRESH OUTPUT.
STRONGEST RECENT BOUNDARY-LAYER DESTABILIZATION, ASSOCIATED WITH
INSOLATION AND THERMAL/MOISTURE ADVECTION, HAS BECOME FOCUSED TO THE
NORTH OF THE GREATER BALTIMORE AREA THE PAST FEW HOURS. UPDRAFT
INFLOW EMANATING FROM THIS ENVIRONMENT, PROBABLY WILL SUPPORT
FURTHER UPSCALE GROWTH AND INTENSIFICATION OF THE CONVECTIVE SYSTEM
INTO AND ACROSS THE GREATER PHILADELPHIA AREA THROUGH 22-23Z. THIS
MAY INCLUDE EVOLVING SUPERCELL STRUCTURES POSING A RISK FOR
TORNADOES, AND INCREASING RISK FOR STRONG TO SEVERE SURFACE GUSTS.
..KERR.. 08/20/2026
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...PHI...CTP...LWX...
LAT...LON 40137604 40567548 40477448 39757423 39187484 38917557
39187615 39667641 40137604
MOST PROBABLE PEAK TORNADO INTENSITY...100-125 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
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