The National Weather Service in Pittsburgh issued a flash flood warning Tuesday evening for much of Allegheny County and surrounding areas after sweltering temperatures gave way to heavy rainstorms.

The weather service extended the warning to 10:15 p.m. — three hours past its original expiration time of 7:15 p.m. — but flooding has already been reported in White Oak, North Versailles, Duquesne and West Mifflin.

Although the heaviest rains have ended, forecasters said light rain is expected to continue through the evening, prompting the closure of a number of flood-prone roads, including the Pennsylvania Turnpike between mile markers 56 and 58.

Duquesne Light said as many as 12,000 of its customers lost power in the storm, many in West Mifflin, McKeesport and Liberty. About half of those customers had power restored by 10 p.m., the utility said.

The majority of customers still experiencing outages should have power restored by 4 p.m. Wednesday, according to the company.

A fire at a substation in Liberty possibly caused by a lightning strike left about 1,000 customers in the borough without power, Duquesne Light said. The company asked residents to report outages or dangerous situations — such as downed wires — by calling Duquesne Light at 1-888-393-7000.

Kennywood Park closed at 5:30 p.m. — five hours early — due to the inclement weather, according to a statement on its website.

Allegheny County listed numerous situations caused by the storms on its official Twitter account:

A house and cars were underwater in the 2400 block of Latrobe Avenue in Liberty, but there was no reported entrapment; 

A tree was blocking the roadway on the Duquesne side of the McKeesport-Duquesne Bridge on Route 837;

A landslide occurred in the 2600 block of West Run Road in Munhall; 

A truck was on a flooded roadway in the 700 block of West Fifth Avenue in McKeesport. Its occupant escaped safely;

Vehicles were also caught in water at the intersection of Duquesne Boulevard and Grant Avenue in Duquesne and at 300 Eden Park Blvd. in McKeesport.

Before storms rolled through the region and cooled temperatures, Pittsburgh had reached 91 degrees with a dew point of 70 percent, according to Rihaan Gangat, a meteorologist with the weather service.

Storms cooled the temperature more than 10 degrees, he said.

Downtown Pittsburgh received slightly more than a half-inch of rain, but areas to the south, including Munhall and White Oak, received nearly 1½ inches, Mr. Gangat said.

Mr. Gangat said most of the severe weather should have ended when the storms passed to the southeast around 6 p.m.

First Published: June 13, 2017, 10:46 p.m.