Had a great flight yesterday, mostly over land, but the last leg was over water and an island (south of Sweden and over to Bornholm). Had a nice smooth flight while over land, unusually, but hit some pretty bumpy air as I hit the coast, and over the island itself.
Sun had just set by the time I hit the coast, which may explain it somehow? I’m used to the flight smoothing out when I fly over water and was a bit surprised by how bumpy it was. I was at 7500ft. It smoothed out near the ground, and I had a nice, smooth final few miles.
Was it the cooling landmass as the sun went down? It was a summer day, but not overly warm, surface temps were in the 22C range, I was sitting at right around freezing at 7500ft.
Temperature inversion. When cool air and hot air mix they create turbulent air and up/down drafts. Common around mountains and when the land temperature shifts when the sun comes up and goes down. Sort of like the tide of the ocean. Land cools down and the air rushes in and then heats up and pushes it all out. You can see this effect well within the Bay Area around San Francisco. Mornings and evenings always have clouds with more clearer weather midday/early afternoon. Flying from water to land and back will create that as they almost always are different in general temperature.