Saturday's 93-degree scorcher wasn't record-breaking, but if it felt like one for the books, blame the humidity.

The heat index -- or "how hot it feels," explained National Weather Service meteorologist John Darnley -- hit a high of 97 degrees at 3:47 p.m. That's when the relative humidity was at 44 percent and the mercury officially rose to 93 degrees. That's just one degree short of the record for July 24, set in 1934 when temperatures reached 98 degrees, Mr. Darnley said.

Pittsburgh and cities along the East Coast were under assault by a high-pressure system called the Bermuda High, which pressed from the Caribbean island inland, reaching as far as Western Pennsylvania to create scorching conditions. Cities in a broad swath of eastern states sizzled and rewrote record books Saturday, with temperatures in the high 90s and 100s.

With the heat and humidity combining for a possible heat index of over 110 degrees, the weather service issued an "excessive heat warning" for the first time this year for an area stretching from south of Washington, D.C. to north of Baltimore, along the Interstate 95 corridor. By midday Saturday, a wide band from lower New England to the Deep South was under a heat advisory.

The thermometer hit 100 degrees in Washington and Baltimore by mid-afternoon, where the heat index was 109. In Norfolk, Va., it was 104 degrees and 108 degrees with the heat index. Elsewhere, record highs for July 24 of 97 degrees in New York and Philadelphia and 99 degrees in Newark, N.J., were reported.

Philadelphia's high of 97 shattered two previous records of 95 set in 1987 and 1968.

Also, Morgantown eked out a record with a high of 94, breaking its previous record for July 24 set in 1987 by just a degree.

UPMC saw eight heat-related cases -- dehydration and heat exhaustion -- Saturday in the Pittsburgh area, UPMC spokeswoman Stacey Simon said.

"Nothing too serious," Ms. Simon said.

About 40 people, mostly senior citizens, visited the city's two cooling centers in Homewood and the South Side.

Elsewhere, uncomfortable Pittsburghers cooled off at Sandcastle Waterpark in West Homestead, which saw about the same number of customers as it normally does on most warm July weekends.

"One thing that is not popular today is our hot tub," said Melissa Kelly, director of groups sales and guest service.

Dave and Andy's Homemade Ice Cream shop in Oakland saw larger crowds, said Manager Wes Shonk. By late afternoon, they'd sold about 30 gallons of ice cream to sweltering customers.

"Things have been pretty busy for us all day," he said.

When hot temperatures are forecast, the shop starts selling lemon sorbet. By late afternoon Saturday, they'd sold 21/2 gallons of it, Mr. Shonk said.

Lucky for Pittsburghers, the National Weather Service was forecasting relief. Thunderstorms tonight should bring temperatures down to the mid- to lower 80s tomorrow and for the rest of the week.

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