Weather Terms


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.