A heat advisory for the region continues until 7 o’clock Friday night, though meteorologists say it could take a few weeks for the high-pressure system causing the heat to break up.

“What it feels like? Like someone is sitting on you. Really. This is a dangerous hot right here. I mean, you know, it’ll fool you. You don’t need to be out in it.”

Or at least be out in it without the right liquids. Raymond Polk and Robert Turner sit under a walnut tree holding quickly-warming beers as they try to cool off from the heat.

Meteorologists call this kind of weather a warm upper level anticyclone. Bobby Boyd of the National Weather Service in Nashville says the heat’s caused by a pocket of high-pressure air looming over us. It covers about half the country right now, and extends from the ground all the way to the altitude at which commercial airplanes fly. He says it works like a bicycle pump.

“If you’re pumping up a bicycle tire, the bottom of that pump gets warmer by compression; it heats up. It’s the same process in the atmosphere. As the air falls downward, it’s warming by compression,” he said.

The heat and humidity make it harder for the body to cool off, raising the risk of heat stroke and dehydration. In response, Nashville’s Office of Emergency Management has sent out a mini-fleet of trucks to distribute water to anyone who looks thirsty.