You can swim through the air on the East Coast this afternoon. It’s a typical hot, muggy summer afternoon, and an approaching cold front is allowing this soupy air to explode skyward and trigger some nasty thunderstorms. It looks like the storms will arrive in the megalopolis just in time for rush hour, of course.

Today will be a pretty interesting weather day across some of the most heavily-populated sections of the East Coast, as there’s a heightened risk for large hail, damaging winds, and tornadoes in major cities like Atlanta, Charlotte, D.C., Baltimore, and Philadelphia. Here’s what you need to know to stay safe.