List of unnamed tropical cyclones

Scope, reasons, and naming overview

Naming has been used since the 1950 season. 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:

• Being missed during a season, usually because of uncertainties in classification in real time. An example of this is the Azores subtropical storm from the 2005 Atlantic hurricane season.
• Disagreements between warning centre and naming centres over intensity of a cyclone. An example of this is Tropical Storm 06W from the 1995 Pacific typhoon season.
• Formation of a cyclone in an area where no official agency is responsible for naming. An example of this is Tropical Cyclone 29P from the 1996–97 South Pacific cyclone season.
• Intentionally left unnamed to avoid confusion. An example of this is the Perfect Storm from the 1991 Atlantic hurricane season.
• Post-operational upgrading. An example of this is Tropical Storm One-E from the 1996 Pacific hurricane season.

North Atlantic Ocean

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.

South Atlantic Ocean

The South Atlantic is not officially classified as a tropical cyclone basin by the World Meteorological Organization and does not have a designated regional specialized meteorological center (RSMC) that gives official names to tropical cyclones. Despite this, in 2011, the Hydrographic Center of the Brazilian Navy began giving unofficial names to tropical and subtropical cyclones in the south Atlantic. Prior to that, a few systems in the south Atlantic were given names.

There has been one system, Tropical Storm 01Q in 2021, that was monitored and designated 01Q by the National Oceanic and Atmospheric Administration (NOAA). However, the Brazilian Navy did not recognize the system as a tropical cyclone and it remains unnamed.

Eastern and Central North Pacific Ocean

Naming began in 1960. Before 1960, a few systems in the central Pacific basin were given names, generally in an ad hoc manner.

Western North Pacific Ocean

The official practice of tropical cyclone naming started in 1945 within the western north 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 cyclones that met the JMA's tropical storm criteria but not those of the JTWC prior to 2000 are excluded. Likewise, systems that met the JTWC's tropical storm criteria but not those of the JMA from 2000 to present are also excluded.

North Indian Ocean

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 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 or subtropical depressions that RSMC La Réunion analyze as having 10-minute sustained windspeeds of at least 65 km/h, 40 mph being named. However, unlike other basins RSMC La Réunion does not name tropical depressions, as they delegate the rights to name tropical cyclones to the subregional tropical cyclone warning centers in Mauritius or Madagascar depending on whether the system is located east or west of the 55th meridian east.

Australian region

South Pacific Ocean

Notes

References

Unless otherwise indicated, all storms come from the following datasets from the Regional Specialized Meteorological Center:

• Atlantic:
• Western north Pacific:
• Northern Indian, western north Pacific, Southern Hemisphere:
• Southwestern Indian Ocean:

References

1. Christopher Landsea. "Subject: B1) How are tropical cyclones named?".
2. Jack Beven & Eric S. Blake. (2006-04-10). "Unnamed Subtropical Storm". [[National Hurricane Center]].
3. "1995 Annual Tropical Cyclone Report". Joint Typhoon Warning Center.
4. RSMC Nadi — Tropical Cyclone Centre. (May 22, 2009). "RSMC Nadi — Tropical Cyclone Centre Best Track Data for 1996/97 Cyclone Season".
5. (April 2, 1997). "Matt Megan's World". The Manawatu Standard.
6. (2008-08-20). "The Perfect Storm October 1991". [[National Climatic Data Center]].
7. Edward Rappaport. (1996-11-07). "unnamed tropical storm (formerly Tropical Depression One-E)". [[National Hurricane Center]].
8. Blake, Eric S. (December 2, 2011). ["Unnamed Tropical Storm: September 1 - 2, 2011"]({{NHC TCR url). United States National Oceanic and Atmospheric Administration's National Weather Service.
9. Benkman, Walter E. (1963). "Tropical Cyclones in the Eastern North Pacific, 1962". United States National Oceanic and Atmospheric Administration.
10. Shaw Samuel. "A History of Tropical Cyclones In the Central North Pacific and the Hawaiian Islands 1832-1979". United States National Oceanic and Atmospheric Administration's National Weather Service.
11. Rappaport, Edward N. (November 7, 1996). "Unnamed Tropical Storm, (formerly Tropical Depression One-E): May 13 - 16 1996". United States National Oceanic and Atmospheric Administration's National Weather Service.
12. Brown, Daniel P. (December 8, 2020). "Unnamed Tropical Storm, (formerly Tropical Depression Seven-E): July 20 - 21 2020". United States National Oceanic and Atmospheric Administration's National Weather Service.
13. Landsea, Christopher W. (June 1, 2014). "Tropical Cyclone Frequently Asked Question". United States National Oceanic and Atmospheric Administration's Hurricane Research Division.
14. Cry, George. (July 1958). "Naming hurricanes and typhoons". Mariners Weather Log.
15. "Mid-Season Review". [[India Meteorological Department]].
16. Gary Padgett. (2002-04-20). "Monthly Global Tropical Cyclone Summary December 2001".
17. Courtney, Joe. "Unnamed Tropical Cyclone (25U)". Australian Bureau of Meteorology.
18. (April 28, 2017). "Tropical Cyclone 22U". Australian Bureau of Meteorology.