In the seamen's speech the zone is referred to as the doldrums because of its erratic weather patterns with stagnant calms and violent thunderstorms. The ITCZ appears as a band of clouds, usually thunderstorms, that circle the globe near the equator.In the Northern Hemisphere, the trade winds move in a southwestern direction from the northeast, while in the Southern Hemisphere, they move northwestward from the southeast.s the ITCZ migrates more than 500 kilometres (300 mi) from the equator during the respective hemisphere's summer season, increasing Coriolis force makes the formation of tropical cyclones within this zone more possible.