A dangerous, long-lasting heat wave that has brought triple-digit temperatures across much of the central and eastern United States was expected to continue Friday and through the weekend. Typical warm summer weather is not likely to return to much of the Northeast and Mid-Atlantic until Monday.<\/p>\n
Around 180 million people were under extreme heat warnings or heat advisories on Friday, and many had already faced several days of severe warnings to avoid going outdoors in the hottest part of the day. Forecasters expect some of the highest temperatures around Philadelphia, which could hit 104. New York was poised to reach 101 and Washington 103.<\/p>\n
But the sweat-inducing forecasts tell only part of the story.<\/p>\n
On Friday, a Salute to Independence Semiquincentennial Parade in Philadelphia for the 250th birthday of the United States was canceled, with the event\u2019s organizers citing \u201cextreme heat\u201d in social media posts<\/a>. In the nation\u2019s capital, organizers of the Great American State Fair postponed all daytime activities until 5 p.m. Eastern, citing the heat in a social media post<\/a>.<\/p>\n That followed conditions on Thursday when the heat snarled rail travel<\/a> along the Northeast Corridor. Even the New England coast<\/a>, a prime vacation destination known as much for its relatively temperate summers as its seafood, slowed under the weight of the humidity as patrons retreated indoors to the comfort of air conditioning.<\/p>\n The heat also put stress on power grids, contributing to scattered outages in New Jersey, New York and Ohio for tens of thousands of utility customers on Thursday, according to the tracking website PowerOutage.us<\/a>.<\/p>\n More records are expected in coming days. By Sunday, the National Weather Service expects that over 100 daily high records will have been shattered.<\/p>\n Key things to know about the heat wave<\/p>\n On Thursday, Central Park hit 100 degrees for the first time since 2012, while Philadelphia hit 103, tying its 1901 record.<\/p>\n Conditions are being made worse by high humidity, leading to oppressive heat index<\/a> readings. This index is a measure of how hot it really feels outside.<\/p>\n Temperatures dipping down only to the low 80s or high 70s are allowing for little relief and forecasters warned of heat-related illnesses. Heat is the leading cause of weather-related deaths in the United States. Here\u2019s what it does to your body<\/a>, and here are tips to stay cool<\/a>.<\/p>\n