If you’ve been sweltering through the oppressive temperatures that arrived over the eastern half of the U.S. with the summer heat dome, chances are you weren’t thinking about making a grilled cheese sandwich on the stove.
Your thoughts were more likely centered on a cold drink or a dish of ice cream.
But go back to that cheesy delight, because it’s a good example of what’s happening outside.
A heat dome occurs when high pressure parks over an area and traps warm air near the surface, while also suppressing clouds and precipitation. It’s almost like a lid on a pot.
If you make a grilled cheese sandwich in a pan and put a lid over it, the cheesemelts faster because the lid traps the heat. Yep, you’ve created a heat dome.
A heat dome is generally linked to the jet stream. While that heat dome was parked over the eastern U.S., the jet stream was moving sharply to the Northeast —from around Baja California to near Lake Michigan—holding the heat dome in place.
When a heat dome sits over a large land area, it creates a kind of feedback loop. High pressure usually means dry weather, and because there isn’t much rain or wind, the heat keeps building. It never cools down very much at night. Short bursts of rain, if they do occur, only add to the humidity.
“The extent of this early summer heat dome over the United States is remarkable. Thanks to scientific advances, we can now show a clear climate change fingerprint in real time using the Climate Shift Index,” said Zachary Labe, Ph.D., a climate scientist at Climate Central, an independent group of scientists and journalists reporting on climate change issues.
The index shows that extreme heat was four to five times more likely to occur due to climate change.
The North Carolina Climate Science Report, prepared independently by North Carolina-based climate experts, suggests this type of heat wave is likely to become more common.
“The likelihood of extreme heat events is projected to increase in the state, making extreme heat a hazard for North Carolinians to be prepared for now and into the future,” the study says.
The heat dome is just one consequence of the “stuck” weather patterns that are increasing as the planet warms, according to a new study that warns of the dangers of long-lasting weather patterns. Ironically, the research suggests the origin of the patterns lies in the rapid warming of the icy Arctic.
Researchers looked at natural atmospheric patterns called planetary waves. These air currents circle the globe and can lead to heat domes or strong storms staying in place for days at a time when they intensify. Those stalled weather systems have tripled over the past 70 years.
The research suggests that the rapid warming in the Arctic, which is heating up four times faster than the rest of the planet, is changing the atmosphere in ways that shift the jet stream and affect those planetary waves.
All the evidence shows that multiple factors, both natural and human-caused, played a role in our collective roasting in the heat dome. But it’s clear that climate change is a definite influence, and summer weather will keep getting more extreme as global temperatures rise.
Both 2023 and 2024 were designated as the hottest years ever recorded.
To learn how summer heat is even more intense in cities, and what can be done to lower the temperature, watch this Sci NC story about urban heat islands.
Cities are hot and only getting hotter. Find out what that heat feels like on the ground.