Tropical cyclones are given designations once they develop to help forecasters and the public differentiate between systems when several are active. Often, once a tropical cyclone reaches winds of 34kts or greater, then it will be given a name of some form. Each basin has a predetermined list of names for each year assigned by the World Meteorological Organization. Some basins, such as the Atlantic Basin, recycle the naming lists every 6 years. Other basins, like the Western Pacific, uses one big naming list, beginning where the previous season left off and then starting over once all names have been used.
The practice of tropical cyclone naming can be traced back to the 1880s, where Meteorologist Clement Wragge of Australia started informally naming systems to set them all apart. This fell out of favor until after World War II, when observations became better. Names were used to provide ease of communication for the U.S. Navy during and after the war in the Pacific. Before naming became formal, tropical cyclones were named after the places, objects, or saints’ feast days on which they affected or occurred.
Naming criteria vary from basin to basin. For the NHC and CPHC Areas of Responsibility, TCs are named once gale force winds are believed to be present or have been observed. Western Pacific and North Indian storms may be named by the JMA when they are deemed as tropical depressions through the ATCF. The Southern Hemisphere requires more of a TC for it to be named, in that gales have to extend a full radian (halfway) around the center of circulation.
Not all tropical cyclones attain gale force winds or names, however, so instead, they are given a special type of designation. The ATCF gives all TCs a designation that begins with a number that indicates the order in which it developed and ends with a letter for the basin it formed in. Below is a list of letters that are assigned to certain basins.
For example, the 13th tropical depression of a West Pacific season would be designated as “13W”. It would then attain a formal name if it gained gale force winds.
Names can be a variety of things. For most basins, they consist of actual human names submitted by different countries. So, for example, Atlantic naming lists include English, Spanish, and French names. Other basins, such as the West Pacific basin, name storms based off native words submitted by a variety of countries within the basin.
On occasion, a name is retired or withdrawn from a naming list. This occurs if a consensus or majority of members of the WMO agree that the system was so devastating, deadly, or notable that a future use of the name would be deemed insensitive to those impacts. Members then vote on replacement names submitted by the countries after each season, and then the name is replaced and will never be used again. Sometimes names are retired not because their associated storm was worthy of retirement, but because the name may have been difficult to pronounce, too similar to a previously retired storm name, or even politically or culturally insensitive.
Very rarely, naming lists can be exhausted, meaning that every name on the list has been used and storms are still forming. This, however, only happens for basins where the naming lists are preset and different for each year, such as the Atlantic and Eastern Pacific Basins. When this happens in these basins, greek letters are used for any storm that develops after every name on the WMO list has been used. The only time that this has occurred was in the Atlantic during 2005, when activity was so high that 6 additional storms developed after the last available name on the list was used. If a greek name warrants retirement, then it will continue to be used despite any potential insensitivities that may surround the name, but this has never happened.
Below is a list of all 6 Atlantic naming lists that will be used in the next 6 seasons. Bolded and italicized names are those that were replacement names for storms retired during the most recent use of the naming list.