Eye: The center portion of the storm around which winds and rain rotate. Winds are calm and skies are clear or partly cloudy when the eye of a storm passes.

Hurricane: A tropical cyclone with winds of 74 mph or more.

Hurricane warning: Hurricane conditions are expected in the warning area, usually within 24 hours. Complete all storm preparations and evacuate if desired by local officials.

Hurricane watch: Hurricane conditions are possible in the area of the watch, usually within 36 hours. Prepare to take immediate action to protect your family and property in case a hurricane warning is issued.

National Hurricane Center: The National Weather Service offices in Dade County, Fla. It is responsible for forecasting tropical storms and hurricanes in the Atlantic Ocean, Caribbean Sea, Gulf of Mexico and the Pacific Ocean east of the International Date Line.

Small-craft advisory: When a hurricane moves within a few hundred miles of the coast, small-craft owners should not venture out into the open ocean.

Storm surge: A large dome of water, often 50 to 100 miles wide, that sweeps across the coastline near where a hurricane makes landfall. The stronger the hurricane and the shallower the offshore water, the higher the surge will be. Along the coast, storm surge is the greatest threat to life and property.

Storm tide: The combination of the storm surge and the normal astronomical tide.

Tropical storm: A tropical cyclone with 39- to 73-mph winds. These storms are assigned names.

Tropical storm warning: Tropical storm conditions are expected in the warning area, usually within 24 hours.

Tropical storm watch: Tropical storm conditions are possible in the watch area, usually within 36 hours.

Tropical depression: A tropical cyclone with maximum sustained winds near the surface of less than 39 mph. These systems are not given names unless their winds reach tropical-storm strength.

Tropical cyclone: The general term for all circulating weather systems (counterclockwise in the Northern Hemisphere) over tropical waters. Tropical cyclones are classified as tropical depressions, tropical storms and hurricanes.

Tropical disturbance: A moving area of thunderstorms in the tropics.