You're not imagining it: The temperatures have gotten more brutal throughout this week's heat wave in Philadelphia.

Sunday, the first day of the heat wave that has already lasted five days, saw a high of 91 degrees. On Thursday, the temperature soared to 98 degrees and the mercury is expected to hit that mark again today.

The National Weather Service says to expect another hot, humid day in Philadelphia. Like Thursday, today will be mostly sunny, with a slight chance of an afternoon thunderstorm.

An excessive heat warning remains in effect until 8 p.m. Saturday, and heat index values of 102 to 107 are expected today. The hottest temperatures will occur between 1 p.m. and 6 p.m.

The hot temperatures have also proved dangerous: Philadelphia recorded its first heat-related death of the summer Thursday, when a 57-year-old man was found dead in his home with the air conditioning turned off.

The warm weather has led people to seek relief in the water, leading to one drowning and another near-drowning in the region Thursday. A Gloucester County man with cerebral palsy drowned in a family pool, and a 7-year-old boy was hospitalized in critical condition after nearly drowning at a West Philadelphia recreation center.

But relief is on the way.

Saturday will likely extend the heat wave to a full week, with an expected high of 94. But the weather service says there's an 80 percent chance of showers and thunderstorms, with some storms likely to bring heavy rain.

Storms Saturday are most likely after 2 p.m., forecasters say.

And after Saturday, high temperatures in the Philadelphia region shouldn't top 90 degrees again for several days. Forecasted highs for next week are 89 degrees on Sunday, 86 degrees Monday and Tuesday, 87 degrees Wednesday and 89 degrees Thursday.

Contact Emily Babay at 215-854-2153 or Follow @emilybabay on Twitter.
Contact the Breaking News Desk at 215-854-2443; Follow @phillynews on Twitter.