Heat Dome Blankets New York—But It’s Different Than The Ones Plaguing The West

Damn, it’s hot outside. Thermometers at LaGuardia Airport reported a second consecutive day of temperatures in the 90s, and another is forecast for Friday. For New Yorkers wondering why, there are only five words: heat dome and climate change.

A heat dome has migrated westward from the Atlantic Ocean over the past day or two, trapping scorching air over the coastal Northeast and pushing away any cooler respite that the area might typically receive from ocean breezes. People are likely familiar with the meteorological term, given a similar event propelled massive wildfires out West earlier this summer.

“Those ones in the Northwest at the end of June were way worse, far worse than what we're seeing in the Northeast today and tomorrow,” said Sean Sublette, a meteorologist with Climate Central, a science and news organization based in Princeton, New Jersey.

Despite the mainstream fervor over heat domes in recent months, these phenomena are actually a regular occurrence during the summertime. As the Capital Weather Gang explains, blazing hot days can cook the air near the surface of the Earth. That hot pocket of gas tries to expand vertically but then gets pushed down by the higher pressure coming from the upper atmosphere.

“This is a big rod, a mountain of air,” Sublette said. “It’s spiraling clockwise, very slowly through the depth of the atmosphere...I mean, 18,000 to 20,000 feet or so.”

As that extra pressure squats on the Northeast area, it heats the air further and diverts other, cooler weather systems away from us. (Fun fact: In 1960, engineer Buckminster Fuller proposed a two-mile “geodesic dome spanning Midtown Manhattan that would regulate weather and reduce air pollution.” We need you here and now, Bucky!)

Climate change comes into play because, in general, it is increasing the frequency of high heat in the tri-state area. Our days are hotter more often. When a heat dome swaggers into town, it layers on top of our human-caused climate change—making what would normally be bad, worse.

Sublette and his colleagues at Climate Central are tracking the global warming contribution in real-time. Heat and humidity extremes like the ones experienced Thursday are far more likely now relative to the 1970s.

“The same type of heat dome that might've produced 90 or 92 degrees [Fahrenheit], 40 or 50 years ago is going to start producing 96, 97 degrees, today,” Sublette said.

It’s so hot that Mayor Bill de Blasio is advising all New Yorkers to stay inside and near air conditioning on Thursday. He also asked residents to take care of each other.

“Keep an eye on your kids if they're out playing. Don't let 'em be outside too long, obviously. Checking in on neighbors, loved ones, our senior citizens” de Blasio said at a Thursday briefing. The city issued an extended heat warning until 8 p.m. tonight. Pools will stay open until then, too. (Here’s a map of the city’s cooling centers in case you need it Friday).

The five boroughs are on course for an average or slightly above average summer when it comes to heat waves. In an average year, there are about 17 days above 90 degrees Fahrenheit, Sublette said. Assuming the region breaks 90 on Friday, that would bring this year's tally to 14. He adds that the last time there were 30-plus days in Central Park at or above 90 was 2010.

But luckily, the main difference between our East Coast heat dome and the ones that hit the West in June and this week is the duration. The western heat waves are lasting up to a week or longer, while New York’s dome is expected to dissipate by this weekend.

Katherine Fung and Jen Carlson contributed to reporting.