#3 CYCLONE FORMATION
How do cyclones form? The above figure shows how cyclones form. The green arrows show where warm air is rising. The red arrows indicate where cool air is sinking. • Tropical cyclones form only over warm ocean waters near the equator. • To form a cyclone, warm, moist air over the ocean rises upward from near the surface. As this air moves up and away from the ocean surface, it leaves is less air near the surface. So basically as the warm air rises, it causes an area of lower air pressure below. • Air from surrounding areas with higher air pressure pushes in to the low pressure area. Then this new “cool” air becomes warm and moist and rises, too. And the cycle continues… • As the warmed, moist air rises and cools the water in the air forms clouds. The whole system of clouds and wind spins and grows, fed by the ocean’s heat and water evaporating from the ocean surface. • As the storm system rotates faster and faster, an e