NEW YORK (AP) — A record-smashing heat wave broiled the U.S. East for another day Wednesday, even as thermometers were forecast to soon plunge by as many as 30 degrees in the same areas.

The day’s heat wasn’t expected to be as intense as Tuesday, when at least 50 heat records were matched or broken and 21 places hit triple-digit temperatures. About 127 million Americans remained under National Weather Service heat advisories, down from the previous day. Sizzling temperatures sent utilities scrambling to keep the air conditioning and lights on amid massive demand for power.

“It’s still going to be, I think, pretty bad across the East,” meteorologist Bob Oravec of the Weather Prediction Center said Wednesday morning. “I think today is probably the last day of widespread record potential. It might not be quite as hot as yesterday by a few degrees. But still, high temperatures are expected in the upper 90s across a good section of the East.”

The weather service warned of “extreme heat” for a stretch of the country from North Carolina to New York and west to West Virginia. Highs could approach triple digits from New York to Richmond, Oravec said. Temperatures again broke 100 on Wednesday at New York’s John F. Kennedy Airport and in Newark and Baltimore.

Temperatures Wednesday morning were “a little bit warmer than expected” because of northwesterly winds bringing “warm leftovers from yesterday,” said former NOAA chief scientist Ryan Maue, a private meteorologist. Nantucket, Massachusetts, was above 90 degrees Fahrenheit when its forecast high was 82.

The high pressure heat dome that has baked the East was forecast to break. A cold front began moving south from New England, bringing with it clouds and cooler temperatures — not only cooler than 100 degrees Fahrenheit, but cooler than normal.

That air mass drawing on cool ocean waters will send temperatures plummeting by the end of the week in Philadelphia, which hit a record high of 101 degrees Fahrenheit on Tuesday, said Ray Martin, meteorologist at the National Weather Service in Mount Holly, New Jersey. Air temperatures will be in the low 70s Fahrenheit.

“It’s going to feel like a shock to the system, but it’s not anything particularly unusual,” said Martin.