Prolonged heat wave baking much of central, eastern Lower 48

A significant heat dome has been crowding weather maps over the Lower 48 states for the past week, bringing blistering temperatures that have toppled records. Highs have spiked 10 to 20˚F (11˚C) above average in spots, and some places have endured their hottest and most humid weather ever observed during June.

Now the heat dome is languishing over the Tennessee Valley and bringing highs of 95 to 100˚F (35 to 38˚C) from the Corn Belt to the Carolinas, with exceptional humidity in the Midwest exacerbating just how sultry it feels. High humidity levels are contributing to heat index values pushing 115˚F (46˚C) in spots.

Because of the punishing combination of heat and humidity, more than 95 million Americans are under excessive heat warnings or heat advisories from the Florida Panhandle to northern Michigan.

A new pulse of heat, meanwhile, is on the horizon and looks to become established into early next week. There are signs that the anomalously toasty temperatures could linger 7 to 10 days or more, taking a toll on heat-stressed residents.