(Philadelphia) -- Heat warnings and advisories are in effect across much of eastern Pennsylvania as temperatures are heading back into the 90s. 

Head advisories are in place in Reading and Allentown, and an excessive heat warning is in effect for Philadelphia and surrounding counties through Friday night.

The National Weather Service says temperatures in the mid-90s and dew points around 70 will send heat index values up to about 100 degrees.

In the midstate, the hottest day will likely be Thursday, when the heat index could make it feel like 104 degrees in the afternoon.

Forecasters are expecting the heat to continue through Friday and possibly Saturday.