Lingering widespread heat is expected to trigger another round of severe weather and possible flash flooding in parts of the mid-Atlantic and South on Sunday.

July 4 heatwave: A severe heatwave is gripping millions across the US, threatening July 4th celebrations with record-breaking temperatures and dangerous humidity. Outdoor events…

Much of the nation was stewing under 90 to 100-degree heat, which is expected to move south and west by the beginning of next week.