650  
ACUS11 KWNS 211753  
SWOMCD  
SPC MCD 211753  
MDZ000-DEZ000-VAZ000-DCZ000-WVZ000-211930-  
 
MESOSCALE DISCUSSION 1691  
NWS STORM PREDICTION CENTER NORMAN OK  
1253 PM CDT TUE JUL 21 2026  
 
AREAS AFFECTED...PORTIONS OF THE MID-ATLANTIC  
 
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY  
 
VALID 211753Z - 211930Z  
 
PROBABILITY OF WATCH ISSUANCE...80 PERCENT  
 
SUMMARY...MULTIPLE ROUNDS OF NUMEROUS, STRONG TO SEVERE  
THUNDERSTORMS WILL BRING A RISK FOR PRIMARILY DAMAGING WIND GUSTS TO  
PORTIONS OF THE MID-ATLANTIC THROUGH THIS EVENING, WITH A COUPLE OF  
BRIEF TORNADOES AND ISOLATED LARGE HAIL ALSO POSSIBLE.  
 
DISCUSSION...SCATTERED THUNDERSTORMS HAVE DEVELOPED ALONG THE BLUE  
RIDGE AS OF 1750 UTC AHEAD OF A MID-LEVEL SHORTWAVE TROUGH THAT IS  
PROGRESSING EASTWARD ACROSS THE UPPER OHIO VALLEY. EXPECTATION IS  
FOR THIS ACTIVITY TO SPREAD EASTWARD THIS AFTERNOON WITH ADDITIONAL  
THUNDERSTORMS LIKELY TO PROGRESS INTO THE REGION FROM THE NORTHWEST  
THIS EVENING. FILTERED HEATING OF THE DOWNSTREAM ENVIRONMENT HAS  
RESULTED IN TEMPERATURES WARMING INTO THE UPPER 80S/NEAR 90 F. WITH  
DEWPOINTS IN THE LOW/MID 70S, THIS IS SUPPORTING MODERATELY STRONG  
BUOYANCY ACROSS THE REGION. WHILE EFFECTIVE SHEAR OF 35-45+ KTS WILL  
FAVOR STORM ORGANIZATION, WIDESPREAD THUNDERSTORM DEVELOPMENT AND  
COLD POOL CONSOLIDATION ARE ANTICIPATED TO YIELD A  
MULTICELLULAR/OUTFLOW-DOMINANT STORM MODE, WITH DAMAGING TO SEVERE  
WIND GUSTS THE PRIMARY RISK. A COUPLE OF BRIEF TORNADOES AND  
ISOLATED LARGE HAIL WILL ALSO BE POSSIBLE.  
 
ADDITIONALLY, GUIDANCE SUGGESTS THAT AIR MASS RECOVERY WILL OCCUR IN  
THE WAKE OF THESE INITIAL STORMS, WHICH MAY ALLOW THE SEVERE THREAT  
TO PERSIST INTO THIS EVENING AS ADDITIONAL CONVECTION PROGRESSES  
SOUTHEASTWARD INTO THE REGION. GIVEN THIS SEVERE POTENTIAL, WATCH  
ISSUANCE WILL LIKELY BE NEEDED IN THE NEXT HOUR OR TWO.  
 
..CHALMERS/MOSIER.. 07/21/2026  
   
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT  
 
ATTN...WFO...PHI...AKQ...LWX...RNK...  
 
LAT...LON 37348031 38057950 39047840 39467763 39467704 39397660  
39147596 38857550 38557536 38147544 37417580 37067629  
36927689 36917711 36747834 36737931 36818019 37078049  
37218043 37348031  
 
MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH  
MOST PROBABLE PEAK WIND GUST...55-70 MPH  
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN  
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