npub1qn…tsy30 on Nostr: This was in the early evening, just after sunset, so the street would have been warm ...

This was in the early evening, just after sunset, so the street would have been warm while the air would be getting cooler, this would result in a convection current over the street. In other words, a thermal, though this one would have been more like a wall rather than the more circular columns that tend to happen in nature. The buildings on either side of the street probably caused a downdraft at either side too. So look for those conditions and I'm sure you'll see it eventually.