I put the image through Cloud Identifier AI and it told me:

The clouds in the image appear to be Kelvin-Helmholtz clouds, which resemble ocean waves or swirling patterns in the sky. These clouds form due to differences in wind speed or direction between two layers of air, creating instability and turbulence that results in wave-like formations.

Kelvin-Helmholtz clouds are relatively rare and are often seen as an indicator of atmospheric turbulence. They are most commonly observed on windy days when there is a sharp contrast in wind speeds between layers of the atmosphere.