Areas from the Ohio Valley to the mid-Atlantic coastline pummeled by torrential downpours and damaging winds on Saturday should prepare for an encore severe weather event on Sunday.
Storms will threaten to bring damaging wind gusts and blinding downpours to the Interstate-95 corridor from Philadelphia to Washington, D.C., snarling traffic and potentially causing extensive power outages and airline delays.
“The strongest storms will first set up from central and western Pennsylvania to southern Ohio, southern Indiana, much of Kentucky, West Virginia and western Virginia through Sunday afternoon,” AccuWeather Meteorologist Brett Rathbun said.
Similar to Saturday’s storms, the main threats on Sunday will be strong winds capable of knocking down trees and power lines and localized flash flooding.
Any storm that lingers over an area for an extended period of time can quickly turn streets into rivers and small streams into raging torrents of water. Residents living along streams and creeks should remain abreast of flash flood advisories.
Storms will target cities such as Pittsburgh and State College, Pennsylvania, to Elkins and Charleston, West Virginia, and Louisville and Lexington, Kentucky, mainly during daylight hours on Sunday.
By early Sunday evening, storms should begin to rumble eastward off the Appalachian Mountains, slowing traffic on I-81 from Harrisburg, Pennsylvania, to Roanoke, Virginia.
“The daytime hours will be mainly dry from New York City to Philadelphia before wet and stormy weather approaches during the early to late-evening hours,” Rathbun said.
Though residents living in Baltimore and Washington, D.C., may face multiple rounds of storms on Sunday afternoon and evening, the greatest risk for severe weather from the eastern slopes of the Appalachians to the Delmarva Peninsula and Tidewater of Virginia will occur during the evening hours.
A large network of major U.S. interstates, including I-95, 81, 64, and 70, will be impacted by dangerous conditions into Sunday night.
The risk for vehicles hydroplaning and multi-vehicle collisions increases greatly at highway speeds when torrential downpours quickly reduce roadway visibility to near-zero and gusty winds make it difficult for motorists to remain in a single lane.
Across the northern mid-Atlantic and New England, a wedge of cool, more stable air will thwart the risk for severe weather.
By late Sunday night, the storm system causing the violent weather will push off the Eastern Seaboard, allowing a surge of cooler and less humid air to rush into the eastern United States early next week.
“Monday may set up to feel more like fall from northeastern Pennsylvania to New York City and New England as clouds and areas of rain and drizzle make for a damp start to the week,” Rathbun said.
High temperatures will be stuck in the 60s and 70s F for a few days across the northern mid-Atlantic and New England, which is 10 to 20 degrees Fahrenheit below normal for late July.
The October-like chill will be a stark contrast to the extreme heat and humidity scorching the eastern U.S. during recent weeks.
The change in temperatures will be less dramatic in areas farther south in the mid-Atlantic.
While temperatures in the lower to middle 70s replace highs in the 90s in New York City, residents from Philadelphia to Washington, D.C., may notice a bigger drop in humidity than air temperatures.
Temperatures in the southern mid-Atlantic may only fall back 5-10 degrees compared to last week, but a crash in humidity levels may slash AccuWeather RealFeel Temperatures by as much as 20 to 25 degrees.
By the end of the week, heat, humidity and the threat for disruptive thunderstorms may chase away the early preview of autumn across the eastern U.S.