Heatwave Relief? Storms To Roll Through Southeastern PA On Friday

SOUTHEASTERN PA — Severe weather is once again expected to hit the greater Philadelphia area this weekend, with scattered thunderstorms, rain, and extreme heat forecasted for Friday and beyond.

A flash flood watch is in effect from 2 p.m. Friday through 2 a.m. Sunday. A heat advisory issued by the National Weather Service is in effect for the five-county area and more through Friday at 8 p.m., as the heat index pushes the 100-degree mark.

A slow-moving storm system is expected to bring scattered thunderstorms, torrential downpours, and damaging winds on Friday after 2 p.m. into the evening, with additional storms forecasted through Saturday, officials said.

Showers & thunderstorms will develop this afternoon & tonight. Although damaging winds are possible, our main concern is for heavy rain which could lead to flash flooding. A Flash Flood Watch is in effect through Saturday. Be aware for Flash Flood Warnings! pic.twitter.com/PqetR7gcfG
— NWS Mount Holly (@NWS_MountHolly) August 27, 2021

With weak storm motion and heavy rain, the National Weather service said there is also a possibility for localized flash flooding, particularly in more vulnerable urban areas and in locations that received substantial rainfall in recent weeks.

"With hot and humid conditions in advance of this system, storms will likely produce torrential downpours. As storms are also expected to be slow-moving, there is elevated potential for localized flash flooding," the agency said.

The National Weather Service also issued a hazardous weather outlook for most of the region Friday morning, in effect through Thursday of next week. A hazardous weather outlook is issued when there is a potential for severe weather events.

The extreme heat is expected to let up on Saturday, with temperatures dropping to the low 70s and a chance of scattered showers, according to AccuWeather. Sunday is predicted to be humid and see intervals of clouds and sun.

Here's the latest forecast:

Friday: A chance of showers and thunderstorms, mainly after 2pm. Some of the storms could produce heavy rain. Increasing clouds, with a high near 92. Heat index values as high as 101. Calm wind becoming southwest around 5 mph in the afternoon. Chance of precipitation is 40%. New rainfall amounts between a quarter and half of an inch possible

Friday Night: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 2am. Some of the storms could produce heavy rain. Patchy fog after midnight. Otherwise, mostly cloudy, with a low around 74. Northeast wind around 5 mph. Chance of precipitation is 60%. New rainfall amounts between a half and three quarters of an inch possible.

Saturday: Showers likely and possibly a thunderstorm before 8 am, then a chance of showers and thunderstorms between 8am and 2pm, then showers likely and possibly a thunderstorm after 2pm. Some of the storms could produce heavy rainfall. Patchy fog before 2pm. Otherwise, mostly cloudy, with a high near 82. Northeast wind 5 to 10 mph. Chance of precipitation is 70%. New rainfall amounts between a half and three quarters of an inch possible.

Saturday Night: Showers likely and possibly a thunderstorm before 8pm, then a chance of showers and thunderstorms between 8pm and 2am. Some of the storms could produce heavy rainfall. Patchy fog after 2am. Otherwise, mostly cloudy, with a low around 70. East wind 5 to 10 mph. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.