It was rough around the studio last night- the sidewalks were a river and we could not see outside of the studio windows- it looked as if the studio were going through a powerful car-wash!

Severe thunderstorms on Sunday evening knocked out power to thousands across southeast Wisconsin, caused flash flooding and even disrupted the Big Gig.

The storms left roughly 40,000 We Energies customers without power, a company spokesman said.

The power failures were scattered throughout the city and attributed to downed power lines and lightning strikes, said Barry McNulty, a We Energies spokesman.

The storms temporarily delayed performances at Summerfest, but the show went on with all headliner acts scheduled to perform, a Summerfest news release said.

National Weather Service Doppler radar estimated that more than 4 inches of rain fell Sunday over parts of Milwaukee County, especially along the east-west portion of I-94.

The intense storms prompted a flash flood warning in Milwaukee County that was to last through 11 p.m.

Flooding forced the closure of several city streets and caused several cars to stall, according to the agency Web site and police.

The Menomonee River in Wauwatosa, which has a flood stage of 11 feet, was at 10.8 feet at 9:15 p.m. and flooding appeared "imminent," according to the National Weather Service.

There were no immediate reports of injuries as a result of the storms.

Extra crews from Milwaukee's Department of Public Works were called in late Sunday to clear downed trees and handle dozens of reports of flooded streets, spokeswoman Cecilia Gilbert said.

Most of the flooding occurred on the city's south side.

High winds downed power lines and toppled trees. Some areas had hail more than an inch in diameter, the weather service said.

The forecast for Tuesday and Tuesday night calls for more thunderstorms.