Temperatures around 100 degrees are possible in Washington, D.C, Baltimore, Philadelphia, New York City, Boston, Chicago, and St. Louis, AccuWeather said. For a while on Saturday, it will feel about as hot in Washington, D.C., as it is in Death Valley, California, according to AccuWeather.
Dozens of record hot temperatures are likely, the National Weather Service said, as the heat index is forecast to surge past 100 degrees and approach the 110s in many areas. The heat index, also known as the apparent temperature, is what the temperature feels like to the human body when relative humidity is combined with the air temperature.
Heat exhaustion and heat stroke are the primary health issues emergency rooms could see. Both can occur after temperatures hit 80 degrees or the humidity rises above 75 percent, according to Eskenazi Health in Indianapolis.
Heat stroke can lead to permanent brain damage and death if not treated promptly, said Dr. Tyler Stepsis, medical director of the Michael & Susan Smith Emergency Department at Eskenazi Health.
“Spending too much time in high temperatures and elevated humidity conditions, along with dehydration, may create an extremely dangerous situation where the core body temperature exceeds 104 degrees Fahrenheit,” Stepsis said.
Those without air conditioning, elderly, small children, and pets are especially susceptible, the weather service said.
At least one death has been blamed on the heat: Former New York Giants offensive lineman Mitch Petrus, 32, died of heat stroke Thursday night at a North Little Rock hospital after working outside that day at his family’s shop about 25 miles east of Little Rock.
Nights will also provide little relief: According to AccuWeather, temperatures in many of the big cities may struggle to drop below 80 degrees at night, which then allows the heat to build at an even faster pace the next day. Nighttime humidity levels can be significantly higher than the afternoon as a result.
It's not the heat, it's the .... dew point.... pic.twitter.com/rLBU98y0Hq— USA TODAY Weather (@usatodayweather) July 19, 2019
At those levels, nighttime provides little relief for people that may not have additional or adequate cooling resources and the body has to work harder to cool itself, according to University of Georgia meteorologist Marshall Shepherd.
Some good news: The worst of the heat is forecast to ease by early next week, returning temperatures back to more typical July levels in the central and eastern U.S., the weather service said.
According to the Weather Channel, by Monday and into Tuesday, cooler, drier air will spread across much of the Plains, Midwest and East, dropping temperatures near or even below average for late July. This could mean highs in the low- to mid-80s across those regions, with temperatures dropping into the 60s or lower overnight.
Contributing: The Associated Press
This article originally appeared on USA TODAY: Heat index forecast to hit 110 degrees in many parts of the US