A dangerous and likely record-setting heat wave is set to engulf the U.S. as millions prepare for the July 4th holiday. Over 230 million people are expected to feel the effects of a heat dome, leading to extreme temperatures and high humidity levels across various regions, including the Midwest and East Coast. Health experts are warning of life-threatening conditions, with heat index values soaring to triple digits. Many states, including Connecticut and Minnesota, have activated emergency heat protocols in response to the extreme weather. As thunderstorms may also emerge, the impending heat spells challenges for communities, urging residents to stay informed and prepared.