List of unnamed tropical cyclones


The list of unnamed tropical cyclones since naming began includes all tropical cyclones that met the criteria for naming in a basin, but that for whatever reason, did not receive a name. These systems have occurred in all basins and for various reasons.

Scope, reasons, and naming overview

In order to ease communications and advisories, tropical cyclones are named when, according to the appropriate Regional Specialized Meteorological Center or Tropical Cyclone Warning Center, it has reached tropical storm status. A tropical cyclone with winds of tropical storm intensity or higher goes unnamed when operationally, it is not considered to have met the criteria for naming. Reasons for this include:
Only unnamed subtropical cyclones that could have been named are included. This excludes several that existed, but that were unnamed because subtropical cyclones were not named when they existed.
Naming has been used since the 1950 season.
Naming began in 1960. Before 1957, a few systems in the central Pacific basin were given names, generally in an ad hoc manner.
The official practice of tropical cyclone naming started in 1945 within the Western Pacific. Due to differences in wind speed criteria between the Japan Meteorological Agency and the Joint Typhoon Warning Center, a system will sometimes be considered a tropical storm by the JTWC but only a depression by the JMA, or vice versa. This results in several apparent unnamed systems. Prior to 2000, the JTWC was responsible for tropical cyclone naming, with the JMA assuming responsibility for naming from 2000 and beyond. Due to this, "unnamed tropical cyclones" that met the JMA's tropical storm criteria but not those of the JTWC prior to 2000 are excluded. Likewise, "unnamed tropical cyclones" that met the JTWC's tropical storm criteria but not those of the JMA from 2000 and beyond are also excluded.
Due to differences in wind speed criteria between the India Meteorological Department and the Joint Typhoon Warning Center, a system will sometimes be considered a tropical storm by the JTWC but only a depression by the IMD. This results in several apparent unnamed systems. Because the IMD is responsible for naming, "unnamed tropical cyclones" that met the JTWC's tropical storm criteria but not those of the IMD are excluded.
Naming has taken place since mid-2003.
There have been no unnamed tropical cyclones using the India Meteorological Department's criteria. One system, 2007's Yemyin, was upgraded after the fact and retroactively named.

South-west Indian Ocean

Tropical cyclones have been named within this basin since 1960, with any tropical depression or subtropical depression that RSMC La Réunion analyze as having 10-minute sustained windspeeds of at least 65 km/h, 40 mph is named. However unlike other basins RSMC La Réunion do not name tropical depressions, however as they delegate the rights to name tropical cyclones to the Subregional tropical cyclone warning centers in Mauritius or Madagascar depending on whether it is east or west of the 55th meridian east.
Subtropical Depression 15 – 2006–07