Love today's image from @DundeeSat !
It shows some gorgeous stripy wave clouds over Scotland 👇
These stripy clouds show that the air is relatively stable at the moment. It's coming from the west, and is being forced to rise as it crossed the Scottish mountains.
As it was 'stable', it was happy at the height it was. Therefore after crossing the mountains, it sinks again, but overshoots and goes too low. So it rises again, and again overshoots, so sinks and continues oscillating.
At the top of its oscillation, the air forms clouds, and the bottom it's cloud free. And this gives the distinctive stripy pattern.