A dangerous heat dome is set to envelop over 230 million Americans as temperatures soar across the Midwest and East Coast. By midweek, it will feel like 100 to 110 degrees for tens of millions as the heat dome expands eastward ahead of America's 250th birthday.

According to the FOX Forecast Center, temperatures in the 90s are spreading across the Midwest and will reach the East Coast, impacting cities like St. Louis, Detroit, Washington D.C., Baltimore, Philadelphia, and New York City.

See the Heat Dome map here

The National Weather Service warns that the heat will be exacerbated by high humidity, leading to heat index values of 105 degrees or higher in the Midwest, Ohio Valley, and Tennessee Valley through Wednesday (July 1) and Thursday (July 2). Forecasters predict that the heat wave will persist into the weekend, with temperatures potentially setting records in several regions.

The AccuWeather HeatWave Counter and Severity Index™ indicates that New York City, Philadelphia, and Chicago will face significant heat waves around the Fourth of July holiday. The heat dome, characterized by a high-pressure system that traps hot air, will limit rainfall and create dry conditions, increasing the risk of wildfires in the West.

Authorities advise residents to stay hydrated, wear lightweight clothing, and seek air-conditioned spaces to mitigate the heat's effects. As the heat dome persists, relief is expected with a shift in the jet stream, potentially bringing cooler air and thunderstorms to the East by Independence Day.