Flash Floods, Extreme Heat Hit Philadelphia Region
Philadelphia faces a dangerous one-two punch: a flash flood warning from thunderstorms dumping up to 2 inches of rain per hour, followed by a week of heat index values that could hit 110 degrees.
PHILADELPHIA, PENNSYLVANIA — A flash flood warning and a multi-day extreme heat watch are affecting the Philadelphia region, with the National Weather Service in Mount Holly, New Jersey issuing both alerts for Philadelphia County and surrounding areas.
Flash Flood Warning Strikes Region Sunday Evening
The National Weather Service in Mount Holly issued a flash flood warning on June 28 at 7:51 p.m. EDT, effective until 10:45 p.m. EDT that same evening. Doppler radar at the time showed thunderstorms dropping heavy rain across the warned area at a rate of 1.5 to 2 inches per hour.
The warning covered a broad swath of the region, including Philadelphia County in southeastern Pennsylvania, Northeastern Delaware County in southeastern Pennsylvania, and Southeastern Montgomery County in southeastern Pennsylvania. In southern New Jersey, the warning extended to Northwestern Burlington County, Northwestern Camden County, and North Central Gloucester County.
Flash flooding was described as ongoing or expected to begin shortly at the time of the warning’s issuance, according to the National Weather Service. Officials warned of flooding impacts to small creeks and streams, urban streets, highways, underpasses, and other low-lying drainage areas. Specific locations identified as at risk included Philadelphia, Camden, Gloucester City, and Norristown.
Extreme Heat Watch Extends Through July 4 Weekend
Separate from the flooding threat, the National Weather Service in Mount Holly also issued an Extreme Heat Watch on June 28 at 2:11 p.m. EDT, running from Wednesday afternoon through Saturday evening, July 4, at 8:00 p.m. EDT. The watch spans multiple counties across Pennsylvania, New Jersey, and Delaware.
Heat index values could reach as high as 110 degrees in some areas, according to the National Weather Service. That most intense heat is expected across New Castle County in Delaware; Mercer, Camden, Gloucester, and Northwestern Burlington Counties in New Jersey; and Delaware, Eastern Chester, Eastern Montgomery, Lower Bucks, and Philadelphia Counties in Pennsylvania.
A second zone covering Morris, Sussex, Warren, and Hunterdon Counties in New Jersey, along with Berks, Lehigh, Northampton, Upper Bucks, Western Chester, and Western Montgomery Counties in Pennsylvania, faces heat index values up to 108 degrees. Carbon and Monroe Counties in Pennsylvania’s Pocono region could see heat indices up to 105 degrees at lower elevations and up to 100 degrees across the Pocono Plateau.
Overnight Temperatures Offer No Relief
Forecasters warned that nighttime temperatures will provide little to no break from the oppressive heat. In the Philadelphia area and lower-elevation counties, overnight lows are expected to remain in the mid-70s to low 80s, according to the National Weather Service.
The combination of sustained high overnight temperatures and multiple days of near-record daytime heat will compound the health risks, the agency noted. The National Weather Service stated that heat-related illnesses increase significantly during extreme heat and high humidity events of this type.
Residents across the region are urged to monitor updated forecasts from the National Weather Service in Mount Holly as conditions develop through the Independence Day holiday weekend.
