The severe thunderstorms that blasted the region midday Wednesday killed at least three people and knocked out power to tens of thousands, officials said.

And threatening weather reappeared Wednesday night, as the National Weather Service announced a tornado warning for parts of Philadelphia, Burlington, Camden, Delaware, Gloucester, and Montgomery Counties.

As of 8:30 p.m., the weather service had not received any confirmed reports that a tornado touched down in the Philadelphia region, but the skies over the city appeared ominous.

Wind gusts of 60 mph were measured at Philadelphia International Airport, the weather service said.

The storm earlier Wednesday — classified as a derecho, based on the speed of the wind and swath of damage — caused two deaths in Lower Merion Township, and one in Lower Moreland Township, according to Montgomery County officials.