Gulf Stream
Strong extratropical cyclones have been shown to deepen significantly along a shallow frontal zone, forced by the Gulf Stream, during the cold season. Subtropical cyclones also tend to generate near the Gulf Stream. 75 percent of such systems documented between 1951 and 2000 formed near this warm water current, with two annual peaks of activity occurring during the months of May and October. Cyclones within the ocean form under the Gulf Stream, extending as deep as beneath the ocean's surface.