(CNN) -- A heat wave is expected to form over the mid-Atlantic region this week as forecasters warn heat indices could reach the triple digits.
Eight states are under heat advisories beginning Wednesday, according to the National Weather Service.
Delaware, Maryland, Virginia, southeast Pennsylvania and southern New Jersey are expecting the heat index to reach from 100 to 105 degrees on Wednesday and Thursday, said National Weather Service meteorologist Rick Watling. Heat indices combine humidity and temperature to estimate how hot the weather feels to the body.
New York, Vermont and Massachusetts might also see near record-breaking temperatures in the triple digits. According to the National Weather Service, the current record high temperature for June in Manhattan's Central Park is 101 degrees, which was reached on June 27, 1966, and June 29, 1934.
The National Weather Service expects the heat wave to begin Wednesday and continue into Friday morning. A cold front expected late Friday, however, will leave the mid-Atlantic region with cooler weather into the weekend, Watling said.
"Heat, of course, is a cumulative effect," Watling said. "One hot day people can tolerate, but a couple, that's when you start seeing people getting sick because they can't cool off, they can't get a break."
The National Weather Service advises residents to take extra precautions in the excessive heat. They're urged to drink plenty of water, reschedule strenuous activities, stay in air-conditioned rooms, stay out of the sun and check in on relatives and neighbors.
Cities across the mid-Atlantic have prepared for the anticipated heat wave by designating cooling centers and advising residents on how to remain safe.
Residents in Boston can cool off in parks with water spray features or in air-conditioned community centers across the city.
In New York, there will be 450 designated cooling centers open across the five boroughs for residents looking to cool off, said Office of Emergency Management spokeswoman Judith Kane.
New York residents are also advised to call 311 or to go to their city's website online to find cooling centers and get information on how to mitigate the heat.