* WHAT...Heat index values up to 93 degrees expected. * WHERE...In New Jersey, Morris, Somerset, Warren, and Hunterdon Counties. In Pennsylvania, Berks, Lehigh, Northampton, Upper Bucks, Western Chester, and Western Montgomery Counties. * WHEN...Until 8 PM EDT this evening. * IMPACTS...Hot temperatures and high humidity may cause heat illnesses. * ADDITIONAL DETAILS...Maximum heat indices near 95 degrees during peak heating this afternoon. 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 this 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.
AI Weather Forecast · Wednesday, May 20, 2026
7 AM – 6 PM
A chance of showers and thunderstorms between 1pm and 5pm, then showers and thunderstorms likely. Mostly sunny. High near 94, with temperatures falling to around 84 in the afternoon. West wind 6 to 13 mph, with gusts as high as 23 mph. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch possible.
6 PM – 6 AM
Showers and thunderstorms likely before 7pm, then a chance of showers and thunderstorms between 7pm and 8pm, then showers and thunderstorms likely. Mostly cloudy. Low around 57, with temperatures rising to around 59 overnight. North wind 7 to 12 mph. Chance of precipitation is 70%. New rainfall amounts between a tenth and quarter of an inch possible.