Philadelphia August 25, 2018 11:28 pm NBC10 First Alert Weather: Tracking a Heat Wave Here comes the heat. The third heat wave of the season is set to begin Monday. NBC10 First Alert Weather meteorologist Steve Sosna has the details as well as Sunday’s forecast. US & World Videos 2:55 One more warm day before temps drop and rain returns 3:08 One more warm day before temperatures drop over the weekend 2:40 How long will this summer-like warmth last? 2:14 The summer preview continues 2:16 Clearing out, warming into the 80s