A Heat Dome Is Headed Toward New York. What Does That Mean?

Summertime blues.

Summer is here, and with it comes the latest apocalyptic-sounding weather phenomenon. A “heat dome” is building in the central United States right now, and it’s going to be so big and intense that a huge swath of the country could be sweating from 100-degree temperatures or higher.

Daily Intelligencer called up New York Metro Weather meteorologist John Homenuk to find out what we’re in store for this week. Homenuk explains that the heat dome is a ridge (high-pressure system) that traps and concentrates hot air. This being summer, these heat domes tend to pop up — but this massive system is anomalous, he says. “We don’t typically see ridges that are this big in that part of the country,” Homenuk explains. The brunt of the heat dome will blast New York City this weekend, so you’ve got a few days to prepare for 90-degree temperatures that, with the good old humidity, could feel like triple digits.

So is the heat dome basically the summer’s polar vortex?

The difference between the polar vortex and this is that this ridge is not coming from somewhere; it’s not displaced somewhere like the polar vortex.

Are we in the spell of the heat dome right now? 
We’re not in it yet. That ridge is going to build over the central United States on Tuesday and Wednesday. By Thursday and Friday, it’s going to start to extend, and it will really build toward our region by the weekend.

What’s the difference between this “heat dome” and it just being hot?
It is just hot. But what kind of distinguishes this from the others is not necessarily the intensity of the heat but the breadth of the ridge. The center of the ridge is going to be near the Texas panhandle, and it’s so large that the heat from it is going to extend all the way to our area.

What should we expect the heat index to be? 
Even though the dew points aren’t going to be dramatically high early on Thursday and Friday, they’re going to build as the weekend goes on. And the temperature itself is going to go into the upper 90s, anyway, so a heat index near 100 is a good bet.

So we’ll probably, most definitely have a heat wave this weekend?
More than likely. I would be shocked if it didn’t.

Well, I guess it is July, so the weather isn’t that surprising.
[Laughs.] No. This is the hottest time of the year typically in our area. Any time the temperature gets to the upper 90s, near 100, it’s definitely worth noting because it’s a big deal. It’s not something that’s going to last one day.

A Heat Dome Is Coming to NYC. What’s That?