515  
ACUS11 KWNS 092044  
SWOMCD  
SPC MCD 092043  
NJZ000-PAZ000-MDZ000-DEZ000-VAZ000-092245-  
 
MESOSCALE DISCUSSION 1620  
NWS STORM PREDICTION CENTER NORMAN OK  
0343 PM CDT WED JUL 09 2025  
 
AREAS AFFECTED...PORTIONS OF  
MARYLAND...DELAWARE...PENNSYLVANIA...AND NEW JERSEY  
 
CONCERNING...SEVERE THUNDERSTORM WATCH 497...  
 
VALID 092043Z - 092245Z  
 
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 497  
CONTINUES.  
 
SUMMARY...CONVECTIVE TRENDS ARE BEING MONITORED FOR THE NEED FOR  
DOWNSTREAM WATCH ISSUANCE ACROSS PARTS OF MARYLAND, DELAWARE,  
PENNSYLVANIA, AND NEW JERSEY AS STORMS SPREAD EAST THROUGH EARLY  
EVENING.  
 
DISCUSSION...REGIONAL RADAR MOSAICS CONTINUE TO SHOW A SLOW, BUT  
STEADY, INCREASE IN CONVECTIVE COVERAGE ACROSS SOUTHERN PA AND PARTS  
OF NORTHERN MD AS LIFT ASSOCIATED WITH A MID-LEVEL IMPULSE CONTINUES  
TO MIGRATE EAST AND OVERSPREADS A MODERATELY BUOYANT AIR MASS.  
REGIONAL VWPS CONTINUE TO SAMPLE 30-40 KNOT MID-LEVEL FLOW  
ASSOCIATED WITH THE UPPER FEATURE, BUT THE NEBULOUS FORCING FOR  
ASCENT AND MODEST MID-LEVEL LAPSE RATES APPEAR TO BE MODULATING  
CONVECTIVE INTENSITY AND LONGEVITY OF MORE DISCRETE CELLS ACROSS  
PA/MD. WHILE THE CONVECTIVE PARAMETER SPACE IS SUPPORTIVE OF  
ORGANIZED/SEVERE CONVECTION, IT REMAINS UNCLEAR HOW INTENSE  
CONVECTION WILL BECOME OVER THE NEXT FEW HOURS.  
 
FURTHER SOUTH INTO EASTERN MD AND DE, CONFIDENCE IS HIGHER IN A  
SEVERE WIND THREAT LATER THIS EVENING. A SQUALL LINE IS SLOWLY  
ORGANIZING ACROSS CENTRAL VA AND IS EXPECTED TO CONTINUE  
INTENSIFYING OVER THE NEXT FEW HOURS (SEE RECENTLY ISSUED MCD #1619  
FOR ADDITIONAL DETAILS). RECENT SURFACE OBSERVATIONS AND MLCAPE  
ANALYSES SHOW A PLUME OF RICH LOW-LEVEL MOISTURE/BUOYANCY EXTENDING  
INTO SOUTHERN DE/SOUTHEAST MD, WHICH SHOULD MAINTAIN THE CONVECTIVE  
LINE AS IT SPREADS EAST INTO THE EVENING HOURS. SLOW STORM MOTIONS  
CAST SOME UNCERTAINTY ON EXACTLY WHEN A DOWNSTREAM WATCH WILL BE  
NEEDED, BUT RECENT HIGH-RES GUIDANCE SUGGEST A DAMAGING WIND THREAT  
WILL BEGIN TO MATERIALIZE BETWEEN 23-01 UTC.  
 
..MOORE.. 07/09/2025  
   
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT  
 
ATTN...WFO...PHI...AKQ...CTP...LWX...  
 
LAT...LON 39057445 38737476 38387493 38137505 37887521 37787541  
37867579 38117608 38547620 39057635 39297654 39487691  
39717717 39927727 40127722 40397661 40527587 40457514  
40247461 40057432 39787409 39477417 39057445  
 
MOST PROBABLE PEAK WIND GUST...55-70 MPH  
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN  
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