Kelvin-Helmholtz Instability manifested in clouds.
It happens when two mediums (wind and cloud) meet at different velocities and produce waves. Sort of like blowing across a glass of water.
Anyone want to skydive and ‘surf’ the clouds? It might just be a bumpy ride… On the topic of turbulence, these Kelvin-Helmholtz clouds indicate an area of just that. If no moisture or clouds were present, clear air turbulence (CAT) would very likely be occurring. This is due to an inversion being present at the base of the clouds. An inversion is a warming with height, thus creating a stable layer in the atmosphere below. The inversion in the picture above would extend from the surface to the base of the clouds (planetary boundary layer ‘PBL’). Above the inversion (free atmosphere) is where there will be an increase in wind speed with height at a significant rate. This speed shear above the inversion in causing the clouds to break over resembling waves. The increase in wind speed above the inversion is enabled by density differences experienced between the PBL and free atmosphere and less friction.
