Formation of stratocumulus radiatus in a relatively stable atmosphere but with a sheared environment as indicated by the weather sounding on the second thumbnail. The wind shear was mainly speed shear though as wind increased rapidly with height. The cloud formation was triggered by a large low pressure system covering most of Europe which in itself was caused by a split polar vortex as indicated in the very last thumbnail. This is caused when high pressure over the North Pole splits the polar vortex in two hence generating low pressure systems underneath it. The difference between this and undulatus is very subtle and not so clear but both clouds have a parallel shape and form over large bodies of water in Winter. In this case, it seemed that the cloud was dissipating. The first thumbnail shows the original photo without contrast. Contrast in this cloud photo had to be used in order to bring out the cloud characteristics clearly.