Severe Thunderstorms Loom As Heat Waves Continues In Eastern PA

Another day of severe heat will slam the greater Philadelphia region on Wednesday, but some relief could be coming in the form of a few rounds of thunderstorms later Wednesday and again on Thursday, forecasters said.

The heat index will return to more than 100 degrees in much of the region again on Wednesday. A "code orange" air quality alert has also been issued for the second consecutive day, as Canadian wildfire smoke mixes with the hot air to produce ozone, the Pennsylvania Department of Environmental Protection said.

A heat advisory remains in effect for the entire region until 8 p.m. Wednesday.

Isolated severe thunderstorms could move through the area later in the afternoon and evening, anywhere from 2 p.m. to. 9 p.m., the National Weather Service said, though they're most likely to hit northwest of the I-95 corridor.

Forecasters gave a 20 to 30 percent chance of storms hitting Wednesday, with damaging winds seen as the most likely severe impact.

That initial front will cool things off slightly, as the high Thursday will be "only" 89.

The storm front on Thursday will be more widespread and severe, with thunderstorms "capable of producing locally heavy rainfall" of up to one to two inches per hour, the National Weather Service said. Localized amounts of up to three inches per hour are possible in the most severe cares.

Scattered flash flooding is possible, and urbanized areas and small streams especially are at risk, forecasters said.

Here's the full forecast for the week and weekend ahead, according to the National Weather Service:

Wednesday
Sunny and hot, with a high near 98. Heat index values as high as 102. Southwest wind around 5 mph.

Tonight
Mostly clear, with a low around 77. Southwest wind around 5 mph.

Thursday
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 2 p.m. Some of the storms could produce heavy rainfall. Increasing clouds, with a high near 89. East wind 5 to 10 mph. Chance of precipitation is 70 percent. New rainfall amounts between a half and three quarters of an inch possible.

Thursday Night
Showers and possibly a thunderstorm. Some of the storms could produce heavy rainfall. Low around 67. Northeast wind around 10 mph. Chance of precipitation is 80 percent. New rainfall amounts between three quarters and one inch possible.

Friday
Showers and possibly a thunderstorm. High near 72. Northeast wind around 10 mph, with gusts as high as 20 mph. Chance of precipitation is 80 percent. New rainfall amounts between a quarter and half of an inch possible.

Friday Night
A chance of showers before 2am. Mostly cloudy, with a low around 61. Chance of precipitation is 30 percent. New precipitation amounts between a tenth and quarter of an inch possible.

Saturday
Sunny, with a high near 80.

Saturday Night
Mostly clear, with a low around 61.

Sunday
Sunny, with a high near 83.

Sunday Night
Partly cloudy, with a low around 63.