Tropical cyclone naming

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Formation and naming

Tropical cyclones
Development - Structure Naming - Seasonal lists - Full list
Effects
Effects Watches and warnings - Storm surge Notable storms - Retired hurricanes
Climatology and tracking
Basins - RSMCs - TCWCs - Scales Observation - Rainfall forecasting - Rainfall climatology

Presently, most tropical cyclones are given a name using one of several lists of tropical cyclone names. Storms reaching tropical storm strength were initially given names to eliminate confusion when there are multiple systems in any individual basin at the same time which assists in warning people of the coming storm.^[1] In most cases, a tropical cyclone retains its name throughout its life; however, under special circumstances, tropical cyclones may be renamed while active. These names are taken from lists which vary from region to region and are drafted a few years ahead of time. The lists are decided upon, depending on the regions, either by committees of the World Meteorological Organization (called primarily to discuss many other issues), or by national weather offices involved in the forecasting of the storms. Each year, the names of particularly destructive storms (if there are any) are "retired" and new names are chosen to take their place.

1 Naming schemes
2 History of tropical cyclone naming
3 Renaming of tropical cyclones
4 See also
5 References

[edit] Naming schemes

In the North Atlantic and Northeastern Pacific worlds, feminine and masculine names are alternated in alphabetic order during a given season. The gender of the season's first storm also alternates year to year. Six lists of names are prepared in advance, and each list is used once every six years. Five letters — "Q," "U," "X," "Y" and "Z" — are omitted in the North Atlantic; only "Q" and "U" are omitted in the Northeastern Pacific. This allows for 21 names in the North Atlantic and 24 names in Northeastern Pacific.^[2] Names of storms may be retired by request of affected countries if they have caused extensive damage. The affected countries then decide on a replacement name of the same gender, and if possible, the same language as the name being retired.^[3] If there are more than 21 named storms in an Atlantic season or 24 named storms in an Eastern Pacific season, the rest are named as letters from the Greek alphabet. This was first necessary during the 2005 Atlantic season when the list was exhausted.^[4] The World Meteorological Organization determined storm names with Greek letters would not be retired in a meeting in the spring of 2006. In the event a storm reached the magnitude that might otherwise have lead to retirement, the storm would be listed with the retired names with a footnote indicating the Greek letter would still be available for future storms.^[5]

In the Central North Pacific region, the name lists are maintained by the Central Pacific Hurricane Center in Honolulu, Hawaii. Four lists of Hawaiian names are selected and used in sequential order without regard to year.^[2]

In the Northwestern Pacific, name lists are maintained by the WMO Typhoon Committee. Five lists of names are used, with each of the 14 nations on the Typhoon Committee submitting two names to each list.^[2] Names are used in the order of the countries' English names, sequentially without regard to year. Since 1981, the numbering system had been the primary system to identify tropical cyclone among Typhoon Committee members and it is still in use. International numbers are assigned by Japan Meteorological Agency on the order that a tropical storm forms while different internal numbers may be assigned by different NMCs. The Typhoon "Songda" in September 2004 was internally called the typhoon number 18 in Japan but typhoon number 19 in China. Internationally, it is recorded as the TY Songda (0418) with "04" taken from the year.^[6] Names are retired from the lists upon request. The most common reason is to memorialize the extensive damage caused by the storm. When names are retired, the contributing member should propose new names. A possible way to do so is through local name nomination contests, which were done in Hong Kong^[7] and China.^[8]

The Australian Bureau of Meteorology maintains three lists of names, one for each of the Western, Northern and Eastern Australian regions. These lists are in alphabetical order and alternate gender, but are used sequentially rather than switched each year. There are also Fiji region and Papua New Guinea region names agreed upon WMO RA V Tropical Cyclone Committee members.^[2]

The RA I Tropical Cyclone Committee for the South-West Indian Ocean creates the lists of names for the Southwestern Indian Ocean. The committee adopted two separate lists of names for the 2006-07 and 2007-08 tropical cyclone seasons at its October 2005 meeting in Gaborone, Botswana. Nominations for the lists were submitted by Mauritius, Malawi, Mozambique, Namibia, Seychelles, South Africa, Swaziland, Zimbabwe, Tanzania, Botswana, Comoros, Lesotho, and Madagascar. If a tropical disturbance reaches "moderate tropical storm" status west of 55 degrees east longitude, then the Sub-regional Tropical Cyclone Advisory Centre in Madagascar assigns the appropriate name to the storm. If a tropical disturbance reaches "moderate tropical storm" status between 55 and 90 degrees east longitude, then the Sub-regional Tropical Cyclone Advisory Centre in Mauritius assigns the appropriate name to the storm.^[9]

[edit] History of tropical cyclone naming

For several hundred years after Europeans arrived in the West Indies, hurricanes there were named after the saint's day on which the storm struck. If a second storm struck on the same saint's day later, it would be referred to as segundo (Spanish for "the second"), as with Hurricane San Felipe Segundo.

The practice of giving storms people's names was introduced by Clement Lindley Wragge, an Anglo-Australian meteorologist at the end of the 19th century. He used female names, the names of politicians who had offended him, and names from history and mythology.^[10]^[11] During World War II, tropical cyclones were given feminine names, mainly for the convenience of forecasters and in a somewhat ad hoc manner. In addition, George R. Stewart's 1941 novel Storm helped to popularize the concept of giving names to tropical cyclones.^[12]

From 1950 through 1952, names from the Joint Army/Navy Phonetic Alphabet were used for storms in the North Atlantic.^[13] The modern naming convention was in response to the need for unambiguous radio communications with ships and aircraft. As transportation traffic increased and meteorological observations improved in number and quality, several typhoons, hurricanes, or cyclones might have to be tracked at any given time. To help in their identification, the practice of systematically naming tropical storms and hurricanes was initiated in 1953 by the United States National Hurricane Center. Naming is now maintained by the World Meteorological Organization (WMO).

In keeping with the common English language practice of referring to named inanimate objects such as boats, trains, etc., using the female pronoun "she," names used were exclusively feminine.^[11] The first storm of the year was assigned a name beginning with the letter "A," the second with the letter "B," etc. Because tropical storms and hurricanes are often destructive, some considered this practice sexist. The WMO responded to these concerns in 1979 with the introduction of masculine names to the nomenclature. It was also in 1979 that the practice of preparing a list of names before the season began. The names are usually of English, French, or Spanish origin in the Atlantic basin, because these are the three predominant languages of the region that the storms typically affect. In the southern hemisphere, male names were given to cyclones starting in 1975.^[11]

[edit] Renaming of tropical cyclones

In most cases, a tropical cyclone retains its name throughout its life. However, a tropical cyclone may be renamed in several occasions.

A tropical storm enters the southwestern Indian Ocean from the east

In the southwestern Indian Ocean, Météo-France in Réunion names a tropical storm once it crosses 90°E from the east, even though it has been named. In this case it will be given a hyphenated name by RSMC La Réunion for a period of about 24 hours.^[14] Examples include Cyclone Adeline-Juliet in early 2005 and Intense Tropical Cyclone Bertie-Alvin in late 2005.
A tropical storm crosses from the Atlantic into the Pacific, or vice versa

It was the policy of National Hurricane Center (NHC) to rename a tropical storm which crossed from Atlantic into Pacific, or vice versa. Examples include Hurricane Cesar-Douglas in 1996, Hurricane Joan-Miriam in 1988,^[15] and Hurricane Cosme-Allison in 1989.^[16] Should a tropical cyclone during its passage over Mexico or Central America maintain its area of low pressure without dissipation into the adjacent tropical cyclone basin, it retains its name. However, a new name is given if the original surface circulation dissipates.^[17] Up to now, there has been no tropical cyclone retaining its name during the passage from the Northeast Pacific to the Atlantic basin, or vice versa, since the policy change in 2001.
Uncertainties of the continuation

When the remnants of a tropical cyclone redevelop, the redeveloping system will be treated as a new tropical cyclone if there are uncertainties of the continuation, even though the original system may contribute to the forming of the new system. One example is Tropical Depression 10-Tropical Depression 12 (which became Hurricane Katrina) from 2005.^[18]
Human errors

Sometimes, there may be human faults leading to the renaming of a tropical cyclone. This is especially true if the system is poorly organized or if it passes from the area of responsibility of one forecaster to another. Examples include Tropical Storm Ken-Lola in 1989^[19] and Tropical Storm Upana-Chanchu in 2000.^[20]