Nearly 60 million people across the Northeastern US are under a heat watch, warning or advisory from the National Weather Service as the worst heat wave of 2018 scorches the most populated region of the country.
Nearly 100 million people will see temperatures climb above 95 degrees Fahrenheit this week, with a majority of those residing in the eastern third of the nation.
High temperatures and high humidity will combine to create a dangerous situation in which heat illnesses are likely.
Several high-temperature records have been set since the heat wave began over the Rockies and Midwest late last week, with Denver tying its all-time record high of 105˚ F on Thursday.
New York City reached 97˚ F on Sunday, its hottest day of the year so far and tying a record for the day set in 2012. The city could top 90 for up to 7 consecutive days this week -- something the National Weather Service in New York has said happens about once every 33 years.
Though the temperatures over the Northeast will not reach the extreme highs in Denver or over the weekend in the Central Plains, the duration of the heat will be significantly longer.
Overnight low temperatures are only expected to dip into the upper 70s, which does not allow buildings (and their occupants) much of a chance to cool off during the overnight hours.
It is the lack of overnight cooling that has proven deadly in past heat waves.
The Northeast will continue to face above-average temperatures until after the July 4 holiday, with only slight chances for afternoon storms as high pressure remains the dominant weather feature.