Meanwhile, in the South, there's an elevated flash flood risk in Alabama, Georgia and Tennessee, where scattered showers and thunderstorms are forecast for Saturday afternoon. Strong, slow-moving thunderstorms could drop rain at 1 to 2 inches per hour.

Canada is battling more than 700 active wildfires across the country, roughly two-thirds of which are burning out of control, according to the Canadian Interagency Forest Fire Center (CIFFC). Smoke billowing from the blazes has blanketed central Canada and the northern U.S., prompting widespread air quality alerts.

Smoke from Canadian wildfires hovered over several Midwestern states Saturday, bringing warnings of unhealthy air for at least the third day.