Advisories are numbered consecutively for each storm. Present location and intensity is described and expected movement is given. Tropical cyclones advisories are issued at six-hour intervals – at midnight, 6:00am, 12:00pm (noon) and 6:00pm Eastern Daylight Time.
Each message gives the name, center (eye) position, intensity and forecast movement of the tropical cyclone. Hurricane center positions are given by latitude (for example 13.5 degrees north) and longitude (for example 55.0 degrees west).
When the storm moves within range of radars, center position may also be given as statute miles and compass direction from a specified point. Tropical cyclones are not given names until they reach the storm stage – that is, rotary circulation, and constant winds over 38 mph (33 knots).
When you receive a tropical cyclone advisory, note the advisory number, center position, intensity and forecast direction of movement. Mark the center position on the tracking chart. Because hurricanes change direction very quickly, you should listen more carefully to where the storm will go than where it has been.