A “heat dome” is expected to increase temperatures and humidity levels throughout the South and parts of the Midwest this week and will eventually move over the Northeast by the weekend. A heat dome is a high-pressure bubble in the upper levels of the atmosphere that traps hot air and sun radiation underneath it.

True to form for July, another round of searing heat and stifling humidity is on the way. Here's how hot it may get, who will sweat the most and how long it will last.