What is the difference between a tropical disturbance, tropical depression, tropical storm, and a hurricane?
• A tropical disturbance is a discrete system of organized showers and thunderstorms that originates in the tropics and maintains its identity for 24 hours or more. • A tropical depression is an organized system of clouds and thunderstorms with a defined counter-clockwise circulation with maximum sustained winds of 38 mph (33 knots) or less. • A tropical storm is an organized system of strong thunderstorms with a defined circulation and maximum sustained winds of 39 to 73 mph (34-63 knots). • A hurricane is an intense tropical weather system with a well defined circulation and maximum sustained winds of 74 mph (64 knots) or higher.
