National Weather Service Definitions

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Tropical Disturbance: A moving area of thunderstorms in the tropics.
Tropical Depression: An area of low pressure, counter-clockwise rotation of clouds, and winds to 38 mph.
Tropical Storm: A low pressure area with wind speeds increasing to 39-73 mph. A storm is given a name at his point.
Hurricane: When a tropical storm reaches winds of 74 mph or greater, it is classified as a hurricane.
Advisory: A dissemination of hurricane and storm data issued every 6 hours.
Special Advisory: A notice given anytime there is a significant change in weather conditions or warnings.
Intermediate Advisory: A report updating a regular advisory information every 2 to 3 hours, as necessary.
Gale Warning: Wind speeds of 39-54 mph expected
Storm Warning: Wind speeds of 55-73 mph expected.
Hurricane Watch: A hurricane may threaten your area within 36 hours.
Hurricane Warning: A hurricane expected do strike your area within 24 hours or less.
Tornado Watch: Tornadoes and severe thunderstorms are possible for your area.
Tornado Warning: Tornadoes and severe thunderstorms are possible for your area.
Storm Surge: The low pressures and strong winds associated with hurricanes and tropical storms cause the sea level to rise above normal tidal heights, giant waves, and unpredictable currents over a 50 mile area.