Odd thunder from storm

So, today is July 18, 2026. A storm just rolled through Pittsburgh. I got to actually watch it roll in tonight. It was pretty weak sauce as far as storms go. A couple wind gusts, some rain and that was about it.

But, there was an oddity about it. I noticed it maybe ten-minutes before the front hit. A low rumbling roar. Constant. Almost like the sound an airplane. In fact, when I was trying to figure out what I was hearing, I can practically see the airport, so I initially determined it had to be a jet from its persistence, but then there was no doppler effect.

Sometimes, I would see lightning, but it was all cloud to sky. Eventually, I heard a clap that was real close, close enough that I could discern its pitch from the din. Indeed, I was hearing an unending chorus of dozens of small thunderclaps, starting and stopping at their own accord, but layered together. The front passed through fifteen-minutes ago, and the roar is still going on right now.

I like watching storms come in, and I have watched a few a year for many decades, but I've not ever heard that. Kind of weird. Anyone know if there is a name for that?