An announcement issued by the National Hurricane Center for specific areas that a tropical storm or a forecast of tropical storm conditions poses a possible threat to coastal areas generally within 36 hours. A tropical storm watch normally should not be issued if the system is forecast to attain hurricane strength.

Another name for an easterly wave, it is an area of relatively low pressure (trough) moving westward through the trade wind easterlies. Generally, it is associated with extensive cloudiness and showers, and may be associated with possible tropical cyclone development.

The region of the earth located between the Tropic of Cancer, at 23.5 degrees North latitude, and the Tropic of Capricorn, at 23.5 degrees South latitude. It encompasses the equatorial region, an area of high temperatures and considerable precipitation during part of the year.

A hurricane that occurs in the Pacific Region of the Philippines or the China Sea.

One of several names for the twenty-four hour time that is used throughout the scientific and military communities. Other names for this time measurement are Greenwich Mean Time (GMT) or Zulu Time (Z).

Any circular or rotary flow in the atmosphere that possesses vorticity.

The location of the surface and/or flight level center of a tropical or subtropical cyclone obtained by reconnaissance aircraft penetration.

An announcement that is issued when severe weather: 1) has developed; 2) is already occurring and reported; or 3) is detected on radar. Warnings state a particular hazard or imminent danger, such as tornadoes, severe thunderstorms, flash and river floods, hurricanes, etc