The third heat wave of a generally benign summer is about to run out of steam, but with the late-season hot spell, this month is all but certain to finish among the 15 warmest Augusts in the 145-year period of record in Philadelphia.

And while Wednesday's high, 95, fell short of the record for Aug. 29 — 98, set in the mightily hot summer of 1991 — it felt like 100 and qualified as one of the hottest days of a summer long on warmth but short on intense heat waves.

The temperature was expected to crest around 90 on Thursday, and that should be the end of this one.

PJM Interconnection, which operates the power grid in 13 states, including New Jersey and Pennsylvania, on Tuesday reported its highest electricity usage in two years.

A so-called Bermuda high off the Atlantic Coast was luring steamy air across the Northeastern United States, and once again, heat advisories were posted all the way to the Canadian border on Wednesday, with an "excessive heat warning" up for central Massachusetts.

Heat is on in the Northeast, with advisories and warnings.
National Weather Service
Heat is on in the Northeast, with advisories and warnings.

But despite the general warmth of the last two months, the region has largely avoided killer heat waves. Only one heat-related death has been reported in Philadelphia this season.

And this heat wave won't make it past Thursday, as a cool front approaches. The government's Storm Prediction Center has the region in the "marginal risk" zone for severe storms Thursday  and Friday.

After weeks of rain that had a particular pick on areas west of the city, any rain Thursday would end the region's first seven-day completely dry spell since Thanksgiving week.

Shower chances could linger well into the holiday weekend, forecasters said, as the front stalls nearby.

Meanwhile, after more than a month of absolute quiet, the Atlantic tropical-storm season is showing a sign of revival.

The National Hurricane Center says a disturbance near the West African coast has an even shot at  growing into a tropical depression early next week.

Shaded area off African coast shows potential for tropical development.
National Hurricane Center
Shaded area off African coast shows potential for tropical development.

For now, any rain actually might be welcomed by at least one constituency: Those who suffer from ragweed allergies. The Asthma Center reported Wednesday that counts were "very high."