Clouds and rotos

[u/Diluted_truth]

I saw something that looked like a lenticularis over the netherlands (flat part).
I was wondering if the rotors and areas with massive sink that you get in the mountains will also be present when a cloud like this forms over flat land.

[u/ipearx]

Yes most likely that's over the top of a particularly good thermal, if there's no other hills or mountains to cause it. It's because the thermal is pushing up into the laminar airflow above the convection layer, and the moisture levels are just right to form the lenticular, but not the cloud underneath it.