How Are Typhoons Named in Pacific, South China Sea?

A typhoon is the name of a strong tropical cyclone whose development is common in the Western North Pacific Ocean and South China Sea.

Typhoons are named by the Japanese Meteorological Agency based on a database organized by the World Meteorological Organization’s Tropical Cyclone program, which also compiles the list of Atlantic hurricane names.

“The forecasters have a specific list that they draw from,” AccuWeather.com Senior Meteorologist Jim Andrews said. “Periodically, a storm name is retired and a new name added."

However, there are some subtle differences.

For the process of naming storms in the Atlantic Basin, there are 21 possibilities of names to choose from per year, based of six rotating lists, which are recycled every seventh year. For typhoons, there is one list with 140 names submitted from nations in the region such as China, Japan, Vietnam and Cambodia. There is no restrictions to how many can be used in a calendar year.

“Unlike hurricanes, lists are not year-specific, so they scroll through the whole list irrespective of calendar,” Andrews said.

The Philippines are also a part of the list of nations which submit names. However, according to the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA), they will use local names whenever a cyclone is within the Philippine Area of Responsibility (PAR).

For example, when Typhoon Neoguri formed in early July 2014, it became known as Florita after it entered the PAR.

The Philippines' naming process rotates through four different lists of 25 names, with every letter represented except X. Every fifth year the list is recycled. In the event that there are more than 25 tropical cyclones, an auxiliary list of 10 names is used.

There are only 21 names allotted each year for Atlantic hurricanes, because there are not many names with the letters Q, U, X, Y and Z. If 21 named tropical cyclones occur, additional storms will take names from the Greek alphabet according to the National Hurricane Center.

According to the WMO, tropical cyclone or hurricane names selected are those that are familiar to the people in each region. Names used in the Western Pacific reflect names of the people who live there. In the Atlantic Basin, names are commonly of English and Spanish descent.

The WMO states that the process of naming tropical cyclones began years ago in order to help in the swift naming of storms as well as heightening awareness for warnings and community preparedness.

A tropical cyclone in the Western North Pacific is labeled a typhoon if its intensity is between 64 and 129 knots (73 and 148 mph). A storm producing an intensity of 130 knots (149 mph) or greater is labeled a super typhoon according to the Joint Typhoon Warning Center.

In very rare occurrences, hurricanes can be renamed as typhoons, as was the case in August 2014 with Hurricane Genevieve, a Category 4 storm in the Pacific Ocean. The storm strengthened, crossed the international date line into the western Pacific Basin, continued to strengthen and was later designated as a super typhoon, as reported by AccuWeather.com Meteorologist Kristina Pydynowski.

How Typhoons Develop

The origin of typhoons can differ from the origin of hurricanes in the Atlantic.

“Most typhoons form from areas of low pressure that spin up then break away from a large elongated area of low pressure called a monsoonal trough,” said AccuWeather.com Senior Meteorologist Dan Kottlowski.

“This development is different than what we see in the Atlantic which derives most development from West African tropical waves,” he said.

Kottlowski said the ingredients necessary for development and intensification are exactly the same as for North Atlantic hurricanes.

"Warm water, low shear and deep moist air support development and strengthening of West Pacific typhoons," he said.

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