It is going to heat up again. The National Weather Service has issued an Excessive Heat Watch for Friday afternoon (6/29) through Sunday evening.
The Heat Index is expected to reach 100 degrees during the afternoon hours. It will be the worst for those in the urban area, where it’s going to be nasty.
High pressure sliding eastward from the plains toward the Ohio Valley late this week and over the weekend is expected to push a hot and humid air mass into the Philly area. This hot and increasingly humid air mass is anticipated to move into our area Friday and lasting through the weekend. A frontal boundary may stall in our vicinity over the weekend that could result in some isolated but brief cooling thunderstorms.