(CNN) — A nasty combination of heat and humidity will hug much of the eastern U.S. in a giant, sweaty embrace this week.
Temperatures in the Northeast, Mid-Atlantic and Midwest will reach the 90s for the next few days, but that's not the bad part. Heat indices are expected to soar well past 100 degrees, the National Weather Service said.
Heat indices represent how hot the weather feels, based on the actual temperatures and humidity.
A heat advisory was in effect Tuesday for parts of Massachusetts, Connecticut and Rhode Island, as well as much of Michigan. Yes, Michigan.
The sauna-like conditions could shift westward mid-week, covering a large swath of the central and eastern U.S., forecasters said.
"Meanwhile, monsoonal moisture will increase across the southern High Plains, with flash flooding possible," the weather agency said.