Storms hid Mid-Atlantic, tornado in Maryland

(CNN) -- A line of storms threatened the Mid-Atlantic states Thursday afternoon, knocking out power for thousands and bringing at least one tornado to suburban Washington.

The National Weather Service said a tornado had been spotted near Colesville, Maryland. The funnel cloud was moving east at 50 mph, the weather service said.

Officials in Maryland and Virginia said more than 134,000 customers had lost power.

In Pennsylvania, the prestigious U.S. Open golf tournament resumed around noon ET after it was postponed because of severe weather moving into the area.

And the weather situation appeared to be looking up for Philadelphia, near the site of the tournament.

Earlier Thursday, with the words, "Turn around ... don't drown," the National Weather Service warned motorists in and around Lansing and Hastings, Michigan, not to drive through flooded streets.

By 2 p.m ET, streets in Lansing were flooded and some were closed because of high water, according to CNN affiliate WILX.

The storm system had already wracked the Upper Midwest on Wednesday with hail, strong winds and at least one confirmed tornado.

The weather service warns that "only a few inches of rapidly flowing water can quickly carry away your vehicle."

Residents of Fort Wayne, Indiana, received a similar warning. "Flooding is occurring or is imminent," the service said.

CNN affiliate WANE reported Thursday that severe storms damaged northeast Indiana and northwest Ohio.

Damaging winds

A system of straight-line winds that slammed Chicago with 50-mph gusts and golf ball-size hail reportedly bowled over trees and buildings in Auglaize, Ohio, early Thursday, said CNN meteorologist Ivan Cabrera.

Local media in the state reported hundreds of households had lost electricity.

The "derecho," as the windy system is called, usually builds in the Midwest then heads east, he said. "Derecho" is a Spanish word that means straight.

The system resembles a squall line, but instead of potentially producing tornadoes, it sends out a slicing wind.

Derechos usually dissipate quickly, but "this one is holding together pretty good," Cabrera said. It could make it to the East Coast.

Behind it is a band of thunderstorms throwing down lots of lightning and heavy rain.

A broad swath of flood warnings and watches extends from Illinois to the Atlantic.

Federal Emergency Management Agency officials said Thursday that officials have been in touch with its state and local emergency management counterparts and with the National Weather Service as it monitors the system.