A tornado watch issued Wednesday night for Western Pennsylvania has faded into flood watches and warnings, and cleanup after winds, rain and lightning raked the region.
As a torrent of storms tears through the Midwest, the Pittsburgh area continues to face the possibility of severe thunderstorms with damaging winds and heavy rain today, National Weather Service meteorologist Lee Hendricks said.
"There is going to be a great deal of instability in the atmosphere when this system pushes through," he said.
In Pennsylvania, the severe thunderstorm watch impacting Allegheny, Beaver, Fayette, Greene, Washington and Westmoreland counties was set to expire at 6 a.m.
The heaviest rain could affect this morning's rush hour, according to the weather service.
A flood warning was in effect until Allegheny, Washington and Westmoreland counties until 8:15 a.m.
High winds and heavy rain could continue to be an issue later in the morning, meteorologist John Darnley said.
One to 2 inches of rain is likely in much of the area, with the possibility of up to 3 inches, especially north of the Golden Triangle.
A flash flood watch remains in effect through 6 p.m. today.
The principal risk is for flooding of streams and creeks and poor drainage areas, particularly urban areas, Mr. Hendricks said. River flooding is not expected.
Tonight, the entire state is under a flood watch, which extends through Thursday, said weather service meteorologist Kevin Fitzgerald in State College. The greatest risk of flooding is in the state's northern tier, while the worst thunderstorms are expected in southern areas, he said.
Mr. Fitzgerald described the weather system as "very strong relative to the season," but said that such a storm "wouldn't be that big a deal" if it occurred in winter.
Pennsylvania Emergency Management Agency spokesman Cory Angell said officials had ensured two National Guard helicopters were ready if needed for water rescues.
More than one in five Americans from Iowa to Maryland could be impacted before the weather system subsides.
One-and-a-half inch hail and 51 mile per hour winds were reported in Ohio, Mr. Darnley said.
Pittsburgh Mayor Luke Ravenstahl and public safety director Michael Huss encouraged residents to pay attention to how the storm develops and to check on elderly or ill neighbors.
The city called in additional public safety and public works personnel to work Wednesday evening and repositioned some equipment in case it was needed for flooding or downed trees and wires.
The city and the Pittsburgh Downtown Partnership made separate announcements about weather-related cancellations. The weekly farmers' market in Downtown's Market Square is closed Thursday; Citiparks canceled all Wednesday night events.
Also, due to the projected weather as well as earlier rains, the U.S. Golf Association announced Wednesday that it will close the Rose Tree Park in Media for the remainder of the 113th U.S. Open Championship at Merion Golf Club in suburban Philadelphia. Spectators driving to the event will be directed to alternative parking at Granite Run Mall about 3 miles away, a spokesman said.
Associated Press contributed. Lexi Belculfine: email@example.com, 412-263-1878 and on Twitter @LexiBelc. Jon Schmitz: firstname.lastname@example.org, 412-263-1868 and on Twitter @pgtraffic. First Published June 12, 2013 11:15 AM