Tornado outbreak sequence of August 4–8, 2023

An EF2 tornado south of Edinburg, Illinois on August 6

A moist and unstable air mass and very strong winds aloft were present on August 7, with a shortwave trough progressing towards northern portions of Appalachia, and convective available potential energy in the 2500-3500 values yielded for severe thunderstorm development. Thermodynamic and kinematic energy in and east of central portions of the Appalachian Mountains also contributed to thunderstorm development.[9] A level 4/moderate risk for severe weather, along with a 10 percent tornado risk, a significant 45 percent wind risk, and a 15 percent hail risk was issued by the Storm Prediction Center on August 7,[9] including the Washington, D.C. metro area, the first moderate risk in decades for the DC area.[10] Several severe thunderstorms formed ahead of a cold front in eastern Ohio, eastern Kentucky and West Virginia and later congealed into a quasi-linear convective system while approaching Washington D.C., Philadelphia, and Charlotte, North Carolina, bringing widespread damaging winds.[9][11][12]

Over 1,000 preliminary wind reports were recorded as severe weather impacted the East Coast of the United States on August 7.[6] This led to Widespread transit and Amtrak train delays in both the Northeast megalopolis, Great Lakes and Southeastern United States.[22]

A Major League Baseball game between the Washington Nationals and the Philadelphia Phillies was postponed on August 7 due to the inclement weather.[23] The baseball game between the New York Mets and Chicago Cubs saw a 2-hour and 9 minute delay due to the rain.[24] A Carly Rae Jepsen concert at The Rooftop at Pier 17 in New York City was cancelled due to a lightning storm.[25] A 2023 Leagues Cup match between the Philadelphia Union and New York Red Bulls was postponed by a day.[26] Several state governors, including Maryland governor Wes Moore, New York governor Kathy Hochul, and West Virginia governor Jim Justice urged people to stay alert, and to be prepared.[27] Hochul's administration and local officials in New York were on stand-by for clean-up and response efforts, while Justice declared a State of Preparedness for all counties in West Virginia.[27][28] Schools in Tennessee and Georgia were closed.[29][30][31] Tornado watches and warnings were posted across ten states from Tennessee to New York, covering 29.5 million people.[32] U.S. government offices in Washington, D.C. were closed early in anticipation of severe weather.[33] Joe Biden's trip to the western United States was delayed 90 minutes.[32]

A rare flash flood emergency was issued for Cambridge, Maryland, where flood damage and water rescues occurred as 4 inches (100 mm) of rain fell in two hours.[34][35] Power lines fell in Westminster, Maryland, including on MD 140, trapping more than forty people in their cars after live power lines fell behind and in front of vehicles.[36][37] Montgomery Parks closed Sligo Creek Parkway and a road because of the threat for flooding, and damaging winds, causing trees to fall. A U.S. District Court sentencing was postponed due to severe weather, and tolls on I-66 reached nearly thirty dollars.[11] Extra trains were operated by the Washington Metro to assist in people to get to their residences, and the Emergency Operations Center was activated.[11][38] Train stations also operated an extra hour because Beyoncé's tour paid $100,000 to do so for fans to arrive at FedExField in Landover, Maryland, and to help people get home.[39] FedexField was also under a "shelter in place" order due to the imminent severe weather threat, and it was lifted nearly two hours later.[40][41] Despite the severe weather, a Pink concert was allowed to proceed, but inclement weather forced fans at Nationals Park to remain at the concourse.[11] Fallen trees trapped hikers and campers at Fall Creek Falls State Park, and forced the park to close.[42] Damage occurred in eastern Kentucky and western North Carolina.[43] Flooding occurred in numerous towns in Massachusetts, including North Andover, Lowell, and Needham.[44] The Knoxville Utilities Board in Knoxville, Tennessee, stated that the damage across eastern Tennessee was "widespread and extensive".[45]

More than nine airports issued ground stops, including LaGuardia Airport, Ronald Reagan Washington National Airport, Hartsfield–Jackson Atlanta International Airport, and Baltimore/Washington International Airport.[46] More than 1,700 flights were cancelled and nearly 9,000 were delayed across eastern United States airports impacted by severe weather.[47][48] At least one million power outages occurred across the eastern United States, and two people were killed.[49][50]

On August 8, the storms in Colorado produced a 5.25 in (13.3 cm) hailstone in Kirk that became the largest hailstone in state history in terms of diameter.[51]

The American Red Cross were prepared to respond if conditions were necessary.[52]

• Weather of 2023
• List of North American tornadoes and tornado outbreaks
• List of United States tornadoes from July to August 2023