How do you make a hurricane? The recipe calls for two key ingredients: heat and moist air. Hurricanes are caused when intensely low pressure areas form over warm ocean waters, usually in the summer and early fall.
Warm sea surface temperatures of at least 80 degrees fuel hurricanes. Water evaporates off the ocean's surface and then condenses to form clouds and rain. This warms the cool air higher up, causing it to rise even further. The rising air is replaced by more warm humid air from the ocean below, and the cycle continues to draw more and more warm moist air into the developing storm from the ocean surface to the atmosphere.
In tropical thunderstorms, winds carry the heat away, but the heat can build up if there is no wind. This causes low pressure areas to form. Because of the low pressure, winds begin to spiral inward towards the center of the low pressure point, much like water going down a drain. Converging winds are those moving in different directions that run into each other. They help form hurricanes by pushing even more moist, warm air upwards. At the same time, high-pressure air in the upper atmosphere begins to be sucked into the low-pressure center ("eye") of the storm. Wind speeds increase, and a hurricane is born.
All hurricanes have three main parts. Rain bands are the thunderstorms moving outward from the center. An "eyewall" encircles the center of a storm. That's where the strongest winds occur. The center is called the eye of the hurricane. It contains the warmest air, and very little wind.