The science behind the heat dome — ‘a mosh pit’ of molecules
From Texas clear to Georgia, from the Gulf Coast on up to the Canadian border, a mass of dangerous heat has started spreading like an atmospheric plague. In the days and perhaps even weeks ahead, a high-pressure system, known as a heat dome, will drive temperatures over 100 degrees Fahrenheit in some places, impacting some 160 million Americans. Extra-high humidity will make that weather even more perilous — while the thermometer may read 100, it might actually feel more like 110.
So what exactly is a heat dome, and why does it last so long? And what gives with all the extra moisture?
A heat dome is a self-reinforcing machine of misery. It’s a system of high-pressure air, which sinks from a few thousand feet up and compresses as it gets closer to the ground. When molecules in the …