Scattered severe storms will move across the region Monday afternoon and evening. An ongoing heat wave will continue on Monday with the risk of late-day scattered storms that could turn severe. Scattered storms will move across the Philadelphia area on Monday afternoon and evening, impacting the city around 4 p.m. The National Weather Service has issued a severe thunderstorm watch for the entire Philadelphia area until 9 p.m. What's next:A similar weather day is ahead on Tuesday as the Philadelphia area reaches the sixth day of the ongoing heat wave.