Three tropical cyclones of the 2006 Pacific typhoon season at different stages of development. The weakest (left), a tropical depression, demonstrates only the most basic circular shape. A stronger storm (top right) demonstrates spiral banding and increased centralization, while the strongest (lower right), a typhoon, has developed an eye.
A cyclone within the tropics, typically having its thunderclouds organized in a spiral shape with wind speeds on the surface between about 30 and 75 miles (60–120 km) per hour.
