Marine stratocumulus is a type of stratocumulus cloud that form in the stable air off the west coast of major land masses.

The Earth spins on its axis, which results in the Coriolis force pushing the ocean surface water away from the coast in the mid-latitudes.

This results in upwelling of cold water from below that creates a pool of cool water at the surface, which in turn cools the air directly above it.

The surface cooling results in a large temperature inversion at the top of the marine layer.

The stability of the marine layer prevents deep convection, and thus stratiform clouds are formed.