The risk of severe storms has increased in southeastern Pennsylvania Friday as destructive winds, torrential rainfall, and flash flooding are all possible, according forecasters.
The entire region is in the level 2 "slight risk" zone for severe impacts, according to the National Weather Service.
Storms will arrive at around 4 p.m. and serious impacts could linger until around 11 p.m. That would impact everything from the evening commute to First Friday celebrations around the region and other outdoor events like the Phillies vs. Blue Jays game.
The area along and northwest of the I-95 corridor is at greatest risk.
Thunder and lightning strikes are also possible.
Residents are urged to monitor changing weather conditions as the day progresses, as timing and the likelihood of impacts could shift.
"The steamy air sticking around will help provide fuel for the storms," Accuweather Chief On-Air Meteorologist Bernie Rayno said in a statement. "Weak fronts and the edges of high pressure will help focus the storms, allowing some to become severe or produce torrential downpours."
While rain may be light outside of those thunderstorms, localized fronts could be severe enough to cause flash flooding.
Before the storms arrive, however, the day will be extremely hot. Temperatures will rise to 92, but humidity will send the heat index up to 102, forecasters said.
Very humid conditions at night, even after the storms, will not provide significant relief to the heat. Heat illness is possible.
A heat advisory is in place for the whole region until 8 p.m. Saturday night.
Here's the full forecast for the coming week, according to the National Weather Service:
Friday
A chance of showers and thunderstorms, mainly after 5 p.m. Some of the storms could produce heavy rainfall. Increasing clouds, with a high near 92. Heat index values as high as 102. Southwest wind 5 to 10 mph. Chance of precipitation is 30 percent. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Friday Night
Showers and thunderstorms likely, mainly before 1 a.m. Some of the storms could produce heavy rainfall. Patchy fog after 1 a.m. Otherwise, cloudy, then gradually becoming partly cloudy, with a low around 75. Southwest wind around 5 mph. Chance of precipitation is 60 percent. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Saturday
A chance of showers and thunderstorms, mainly after 3 p.m. Patchy fog before 9 a.m. Otherwise, mostly sunny, with a high near 91. Heat index values as high as 101. Southwest wind 5 to 10 mph. Chance of precipitation is 30 percent. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Saturday Night
A chance of showers and thunderstorms before 2 a.m. Mostly cloudy, with a low around 75. Southwest wind 5 to 10 mph. Chance of precipitation is 40 percent. New rainfall amounts between a quarter and half of an inch possible.
Sunday
Sunny, with a high near 92. West wind around 5 mph.
Sunday Night
Mostly clear, with a low around 75.
Monday
Sunny, with a high near 93.
Monday Night
Partly cloudy, with a low around 76.
Tuesday
A chance of showers and thunderstorms after 2 p.m. Mostly sunny, with a high near 93. Chance of precipitation is 30 percent.
Tuesday Night
A chance of showers and thunderstorms before 2 a.m. Mostly cloudy, with a low around 74. Chance of precipitation is 40 percent.
Wednesday
A chance of showers. Partly sunny, with a high near 89. Chance of precipitation is 40 percent.
Wednesday Night
A chance of showers. Mostly cloudy, with a low around 72. Chance of precipitation is 40 percent.
Thursday
A chance of showers. Partly sunny, with a high near 89. Chance of precipitation is 30 percent.
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