Active AlertsLongwood, PA

What: Heat index values up to 99 degrees expected.
Where: In Delaware, New Castle County. In New Jersey, Mercer, Camden, Gloucester, and Northwestern Burlington Counties. In Pennsylvania, Delaware, Eastern Chester, Eastern Montgomery, Lower Bucks, and Philadelphia Counties.
When: Until 8 PM EDT Wednesday.
Impacts: Hot temperatures and high humidity may cause heat illnesses.
Additional Details: Maximum heat indices near 100 degrees during peak heating this afternoon and then again on Wednesday. Given the intensity of this early season stretch of heat and humidity, we are not fully acclimated to it and therefore impacts could be greater if precautions are not taken. Showers and some thunderstorms arrive later Wednesday afternoon and evening which will end this early season heat.

Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors.