PHILADELPHIA - A heat wave is well underway in Philadelphia with the past three days reaching the 90s, but we haven't seen the worst of it yet.Following a high of 91 degrees Monday, 93 degrees Tuesday and 95 degrees Wednesday, it's possible that Thursday and Friday could peak in the upper 90s, according to the FOX 29 Weather Authority.The hottest day of the year so far in Philadelphia was June 30, when a 97-degree high was recorded at Philadelphia International Airport.
This temperature will be challenged both Thursday and Friday.The National Weather Service has issued an excessive heat warning for much of the Delaware Valley through 8 p.m.