Tropical Disturbance An area of thunderstorms in motion in the tropics maintaining its identity for at least 24 hours. A tropical disturbance can develop into a tropical depression. Tropical Depression A closed circulation of low pressure, originating over tropical waters. Winds blow counter-clockwise around a center at speeds less than 39 mph. A tropical depression can develop into a tropical storm. Tropical Storm A closed circulation of low pressure, originating over tropical waters , which blow counter-clockwise around a center at speeds ranging from 39 to 73 mph. A tropical storm is given a name, and can develop into a hurricane. Hurricane A severe tropical storm with winds exceeding 74 mph, originating in the tropical regions of the Atlantic Ocean or Caribbean Sea. Hurricances are categorized using the Saffir-Simpson Scale Tropical Storm Watch Tropical storm conditions pose a possible threat to coastal areas within 36 hours. Tropical Storm Warning A warning that tropical storm winds ranging from 39 to 73 mph and heavy rain are expected in the coastal areas within 24 hours Hurricane Watch Issued by the National Hurricane Center 24 to 36 hours in advance of landfall. Indicates that a hurricane is near enough to everybody in the area covered by the "Watch" that they should listen for advisories and take precautionary measures in case a hurricane warning is issued. This is the time to evacuate if you are in a low lying area. Hurricane Warning Issued by the National Hurricane Center 24 hours or less in advance of the hurricane making landfall. Will indicate the specific areas that winds of 74 mph or higher that are associated with a huuricane are expected. All precautions should be taken immediately.
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