Tropical cyclone naming

Before the formal start of naming, tropical cyclones were named after places, objects, or saints' feast days on which they occurred. The credit for the first usage of personal names for weather systems is generally given to the Queensland Government Meteorologist Clement Wragge, who named systems between 1887 and 1907. This system of naming weather systems subsequently fell into disuse for several years after Wragge retired until it was revived in the latter part of World War II for the Western Pacific. Formal naming schemes have subsequently been introduced for the North Atlantic, Eastern, Central, Western and Southern Pacific basins as well as the Australian region and Indian Ocean.

At present, tropical cyclones are officially named by one of eleven warning centers and retain their names throughout their lifetimes to facilitate the effective communication of forecasts and storm-related hazards to the general public. This is especially important when multiple storms are occurring simultaneously in the same ocean basin. Names are generally assigned in order from predetermined lists, once they produce one, three, or ten-minute sustained wind speeds of more than 65 km/h (40 mph). However, standards vary from basin to basin, with some systems named in the Western Pacific when they develop into tropical depressions or enter PAGASA's area of responsibility. Within the Southern Hemisphere, systems must be characterized by a significant amount of gale-force winds occurring around the center before they are named.

Any member of the World Meteorological Organization's hurricane, typhoon and tropical cyclone committees can request that the name of a tropical cyclone be retired or withdrawn from the various tropical cyclone naming lists. A name is retired or withdrawn if a consensus or majority of members agree that the system has acquired a special notoriety, such as causing a large amount of deaths, damages, impacts, or for other special reasons. A replacement name is then submitted to the committee concerned and voted upon, but these names can be rejected and replaced with another name for various reasons: these reasons include the spelling and pronunciation of the name, the similarity to the name of a recent tropical cyclone or on another list of names, and the length of the name for modern communication channels such as social media. PAGASA also retires the names of significant tropical cyclones when they have caused at least 7009100000000000000♠₱1 billion in damage and/or have caused at least 300 deaths.

North Atlantic Ocean

Within the North Atlantic Ocean, tropical or subtropical cyclones are named by the National Hurricane Center (NHC/RSMC Miami) when they are judged to have intensified into a tropical storms with winds of at least 34 kn (39 mph; 63 km/h). There are six lists of names which rotate every six years and begin with the first letters A—W used, skipping Q and U, and alternating between male and female names. The names of significant tropical cyclones are retired from the lists, with a replacement name selected at the next World Meteorological Organization's Hurricane Committee meeting. If all of the names on a list are used, storms are named after the letters of the Greek alphabet.

Eastern Pacific Ocean

Within the Eastern Pacific Ocean, there are two warning centers that assign names to tropical cyclones on behalf of the World Meteorological Organization when they are judged to have intensified into a tropical storm with winds of at least 34 kn (39 mph; 63 km/h). Tropical cyclones that intensify into tropical storms between the coast of Americas and 140°W are named by the National Hurricane Center (NHC/RSMC Miami), while tropical cyclones intensifying into tropical storms between 140°W and 180° are named by the Central Pacific Hurricane Center (CPHC/RSMC Honolulu). Significant tropical cyclones have their names retired from the lists and a replacement name selected at the next World Meteorological Organization Hurricane Committee.

North Pacific east of 140°W

When a tropical depression intensifies into a tropical storm to the north of the Equator between the coastline of the Americas and 140°W, it will be named by the NHC. There are six lists of names which rotate every six years and begin with the letters A—Z used, skipping Q and U, with each name alternating between a male or a female name. The names of significant tropical cyclones are retired from the lists, with a replacement name selected at the next World Meteorological Organization's Hurricane Committee. If all of the names on a list are used, storms are named using the letters of the Greek alphabet.

Central North Pacific Ocean (140°W to 180°)

When a tropical depression intensifies into a tropical storm to the north of the Equator between 140°W and 180°, it is named by the CPHC. Four lists of Hawaiian names are maintained by the World Meteorological Organization's hurricane committee, rotating without regard to year, with the first name for a new year being the next name in sequence that was not used the previous year. Significant tropical cyclones have their names retired from the lists, with a replacement name selected at the next Hurricane Committee meeting.

Western Pacific Ocean (180° – 100°E)

Tropical cyclones that occur within the Northern Hemisphere between the anti-meridian and 100°E are officially named by the Japan Meteorological Agency when they become tropical storms. However, PAGASA also names tropical cyclones that occur or develop into tropical depressions within their self-defined area of responsibility between 5°N–25°N and 115°E-135°E. This often results in tropical cyclones in the region having two names.

International names

Tropical cyclones within the Western Pacific are assigned international names by the JMA when they become a tropical storm with 10-minute sustained winds of at least 34 kn (39 mph; 63 km/h). The names are used sequentially without regard to year and are taken from five lists of names that were prepared by the ESCAP/WMO Typhoon Committee, after each of the 14 members submitted 10 names in 1998. The order of the names to be used was determined by placing the English name of the members in alphabetical order. Members of the committee are allowed to request the retirement or replacement of a system's name if it causes extensive destruction or for other reasons such as number of deaths.

Philippines

Since 1963, PAGASA has independently operated its own naming scheme for tropical cyclones that occur within its own self-defined Philippine Area of Responsibility. The names are taken from four different lists of 25 names and are assigned when a system moves into or develops into a tropical depression within PAGASA's jurisdiction. The four lists of names are rotated every four years, with the names of significant tropical cyclones retired should they have caused at least 7009100000000000000♠₱1 billion in damage and or at least 300 deaths within the Philippines. Should the list of names for a given year be exhausted, names are taken from an auxiliary list, the first ten of which are published every year.

North Indian Ocean (45°E – 100°E)

Within the North Indian Ocean between 45°E – 100°E, tropical cyclones are named by the India Meteorological Department (IMD/RSMC New Delhi) when they are judged to have intensified into a cyclonic storm with 3-minute sustained wind speeds of at least 34 kn (39 mph; 63 km/h). There are eight lists of names which are used in sequence and are not rotated every few years; however, the names of significant tropical cyclones are retired.

South-West Indian Ocean (Africa – 90°E)

Within the South-West Indian Ocean in the Southern Hemisphere between Africa and 90°E, a tropical or subtropical disturbance is named when it is judged to have intensified into a tropical storm with winds of at least 34 kn (39 mph; 63 km/h). This is defined as being when gales are either observed or estimated to be present near a significant portion of the system's center. Systems are named in conjunction with Météo-France Reunion by either Météo Madagascar or the Mauritius Meteorological Service. If a disturbance reaches the naming stage between Africa and 55°E, then Météo Madagascar names it; if it reaches the naming stage between 55°E and 90°E, then the Mauritius Meteorological Service names it. The names are taken from three pre-determined lists of names, which rotate on a triennial basis, with any names that have been used automatically removed. The names that are going to be used during a season are selected in advance by the World Meteorological Organization's RA I Tropical Cyclone Committee from names submitted by member countries.

Australian Region (90°E – 160°E)

Within the Australian region in the Southern Hemisphere between 90°E – 160°E, a tropical cyclone is named when observations and/or Dvorak intensity analysis indicate that a system has gale force or stronger winds near the center which are forecast to continue. The Indonesian Badan Meteorologi, Klimatologi, dan Geofisika names systems that develop between the Equator and 10°S and 90°E and 141°E, while Papua New Guinea's National Weather Service names systems that develop between the Equator and 10°S and 141°E and 160°E. Outside of these areas, the Australian Bureau of Meteorology names systems that develop into tropical cyclones. If a name is assigned to a tropical cyclone that causes loss of life and/or significant damage and disruption to the way of life of a community, then the name assigned to that storm is retired from the list of names for the region. A replacement name is then submitted to the next World Meteorological Organization's RA V Tropical Cyclone Committee meeting.

Indonesia

If a system intensifies into a tropical cyclone between the Equator-10°S and 90°E-141°E, it will be named by the Badan Meteorologi, Klimatologi, dan Geofisika (BMKG/TCWC Jakarta). Names are assigned in sequence from list A, while list B details names that will replace names on list A that are retired or removed for other reasons.

Papua New Guinea

If a system intensifies into a tropical cyclone between the Equator – 10°S and 141°E – 160°E, then it will be named by Papua New Guinea National Weather Service (NWS, TCWC Port Moresby). Names are assigned in sequence from list A and are automatically retired after being used regardless of any damage caused. List B contains names that will replace names on list A that are retired or removed for other reasons.

When a system develops into a tropical cyclone below 10°S between 90°E and 160°E, then it will be named by the Australian Bureau of Meteorology (BoM) which operates three Tropical Cyclone Warning Centres in Perth, Darwin, and Brisbane. The names are assigned in alphabetical order and used in rotating order without regard to year.

Within the Southern Pacific basin in the Southern Hemisphere between 160°E – 120°W, a tropical cyclone is named when observations and/or Dvorak intensity analysis indicate that a system has gale force or stronger winds near the center which are forecast to continue. The Fiji Meteorological Service (FMS) names systems that are located between the Equator and 25°S, while the New Zealand MetService names systems (in conjunction with the FMS) that develop to the south of 25°S. If a tropical cyclone causes loss of life and/or significant damage and disruption to the way of life of a community, then the name assigned to that cyclone is retired from the list of names for the region. A replacement name is then submitted to the next World Meteorological Organization's RA V Tropical Cyclone Committee meeting. The name of a tropical cyclone is determined by using Lists A — D in order, without regard to year before restarting with List A. List E contains names that will replace names on A-D when needed.

South Atlantic

When a significant tropical or subtropical cyclone exists in the South Atlantic Ocean, the Brazilian Navy Hydrographic Center's Serviço Meteorológico Marinho names the system using a predetermined list of names.