By Daniel Lovering
PITTSBURGH (Reuters) - Severe storms hit the Midwest on Saturday and are expected later in the Northeast, where flash flooding killed at least four people in Pittsburgh on Friday.
Heavy rains submerged cars in flood water that was nine feet deep in places in Pittsburgh, authorities said.
A mother and her two daughters died when water engulfed their vehicle in a low-lying section of the city's Washington Boulevard near the Allegheny River.
Kimberly Griffith, 45, and her daughters Brenna, 12, and Mikaela, 8, were pronounced dead at the scene, a spokeswoman for the Allegheny County medical examiner's office said.
The water pinned their vehicle to a tree and they were unable to escape, authorities said.
Also recovered after the flood was the body of Mary Saflin, 72, who had been reported missing earlier, according to the Allegheny County medical examiner's office.
The Philadelphia area was also soaked by heavy thunder showers Friday, bringing a record rainfall of 12.95 inches for August, close to the record for any month, according to NWS meteorologist Lee Robertson.
The previous record is from September 1999, set when a hurricane pushed rainfall to 13.07 inches.
As more storms were forecast for the region Sunday, the NWS warned in a flood advisory that nearly half of all flood fatalities are vehicle-related.
"As little as six inches of water will cause you to lose control of your vehicle," the NWS stated.
The Weather Channel forecast more storms from the Great Lakes to the Central Plains into Saturday night.
One man died as storms and a tornado roared across northern Wisconsin Friday night, cutting an 8-mile-wide swath 65 miles north of Green Bay and taking out power to around 2,000 homes, officials said.
Douglas Brem, 43, was staying in a rented trailer at a recycling center in the path of the storm, which caused extensive damage to homes, Marinette County Coroner George Smith said.
A fierce thunderstorm in the Chicago area Saturday suspended the Chicago Air & Water Show until about 2 p.m., leaving time for a condensed show. The two-day free annual event was expected to attract around 2 million spectators.
Saturday's thunderstorm threat will shift to the Northeast Sunday.
The Southeastern Virginia Hampton Roads region was spared from severe storm activity, but smoke from a 6,000-acre fire in the Great Dismal Swamp continues to plague the region down into North Carolina.
Virginia's Environmental Quality Department downgraded Friday's air quality red alert in some areas to orange, advising of possible health problems for sensitive individuals.
(Additional reporting by John Rondy in Milwaukee, Cynthia Johnston in Las Vegas, Matthew A. Ward in Chesapeake, Va., David Warner in Philadelphia; Writing by Molly O'Toole and Mary Wisniewski; Editing by Jerry Norton)