India, May 21 -- A dangerous weather warning across the mid-Atlantic and Northeast is active, with millions of residents under caution as meteorologists warned of a potent round of severe thunderstorms. The National Weather Service (NWS) has issued a Severe Thunderstorm Watch for a broad swath of the region, stretching from the District of Columbia through Maryland, Virginia, and into parts of Southern Pennsylvania, as atmospheric conditions align to produce potentially destructive weather.

The alert, which remains in effect through the evening hours, has prompted local officials to urge residents to remain vigilant. The primary concern for forecasters is a line of thunderstorms expected to push eastward, interacting with a hot, unstable...