Typhoon

This article is about Pacific tropical cyclones. For other uses, see Typhoon (disambiguation).

Three different typhoons spinning over the western Pacific Ocean on August 7, 2006

A typhoon is a tropical cyclone that develops in the northwestern part of the Pacific Ocean between 180° and 100°E. For organizational purposes, the northern Pacific Ocean is divided into three regions: the eastern (North America to 140°W), central (140°W to 180°), and western (180° to 100°E). A Pacific typhoon, then, is a tropical cyclone in the northern Pacific Ocean west of 180°. Identical phenomena in the eastern north Pacific are called hurricanes, with tropical cyclones moving into the Western Pacific re-designated as typhoons.

Within the Northwestern Pacific there are no official typhoon seasons as tropical cyclones form throughout the year. The majority of storms form between May and December whilst tropical cyclone formation is at a minimum between January and April. The Northwestern Pacific features some of the most intense tropical cyclones on record.

Etymology

The term Typhoon is related to Chinese (simplified Chinese: 台风; traditional Chinese: 颱風; pinyin: Táifēng), meaning great (tái, 颱) and wind (fēng, 風, and in Japanese 台風 (tai-fu). In plural, one can add an "s" at the end in English although in Chinese, "Táifēng", as with "Taifu" in Japanese, is always pronounced the same for both singular and plural. An alternative possible etymology of typhoon is from the greek τύφειν (typhein), to smoke, supposedly borrowed from Arabic language (as طوفان Tufân) to describe the cyclonic storms of the Indian Ocean.

Warning Centers

Within the Western Pacific the Japan Meteorological Agency's Regional Specialized Meteorological Center in Tokyo has the official warning responsibility for the whole of the Western Pacific. However each National Meteorological and Hydrological Service within the western Pacific has the responsibility for issuing warnings for land areas about tropical cyclones affecting their country.

Climatology

Nearly one-third of the world's tropical cyclones form within the Western Pacific. This makes this basin the most active. Pacific typhoons have formed year round, with peak months from August to October. The peak months correspond to that of the Atlantic hurricane seasons. Along with a high storm frequency, this basin also features the most globally intense storms on record. One of the most recent extraordinary years was 1997.

Most intense Pacific typhoons

	Typhoon	Season	Pressure
			hPa	inHg
1	Tip	1979	870	25.7
2	June	1975	875	25.8
	Nora	1973
4	Forrest	1983	876	25.9
5	Ida	1958	877	25.9
6	Rita	1978	878	26.0
7	Kit	1966	880	26.0
	Vanessa	1984
9	Nancy	1961	882	26.4
10	Irma	1971	884	26.1
11	Nina	1953	885	26.1
	Joan	1959
	Megi	2010
Source: JMA Typhoon Best Track Analysis Information for the North Western Pacific Ocean.

Storm Frequency
Tropical storms and Typhoons by month,
for the period 1959–2005 (Northwest Pacific)

Month	Count	Average
Jan	28	0.6
Feb	15	0.3
Mar	26	0.6
Apr	39	0.8
May	64	1.4
Jun	96	2.0
Jul	215	4.6
Aug	312	6.6
Sep	262	5.6
Oct	219	4.7
Nov	134	2.9
Dec	75	1.6
Annual	1484	31.6
Source: JTWC

Actually the area of the Pacific Ocean known as the Federated States of Micronesia, (FSM) or Chuuk (formerly Truk) is the birthplace of 90% of all typhoons in the northern Pacific. The Shallows Seas in that area are easily heated, thereby creating the perfect conditions for spawning Typhoons.

Most active West Pacific seasons

The following are the most active Western Pacific seasons, according to the Joint Typhoon Warning Center best track. Only seasons with at least 30 storms are included.

Total Storms	Year	Tropical Storms	Typhoons	Super Typhoons
39	1964	13	19	7
35	1965 1967 1971	14 15 11	10 16 16	11 4 4
34	1994	14	14	6
33	1996	12	15	6
32	1974	16	16	0
31	1989 1992	10 9	15 17	6 5
30	1962 1966 1972 1990 2004	7 10 8 9 10	17 17 20 17 13	6 3 2 4 7

Paths

Tracks of all tropical cyclones in the northernwestern Pacific Ocean between 1980 and 2005. The vertical line to the right is the International Date Line.

Typhoon paths follow three general directions.

• Straight. A general westward path affects the Philippines, southern China, Taiwan, and Vietnam.
• Recurving. Storms recurving affect eastern China, Taiwan, Korea, and Japan.
• Northward. From point of origin, the storm follows a northerly direction, only affecting small islands.

If viewed at the starting point of these tracks with a political map overlay, the Islands of CHUUK are at the center of the initial starting points in this illustration.

Basin monitoring

The following agencies monitor typhoons:

• Joint Typhoon Warning Center
• Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA)
• RSMC Tokyo-Typhoon Center, part of the Japan Meteorological Agency

Name sources

The list of names consists of entries from 17 East Asian nations and the United States who have territories directly affected by typhoons. The submitted names are arranged into five lists; and each list is cycled with each year. Unlike hurricanes, typhoons are not named after people. Instead, they generally refer to animals, flowers, astrological signs, and a few personal names. However, PAGASA retains its own naming list, which does consist of human names. Therefore, a typhoon can possibly have two names. Storms that cross the date line from the Central Pacific retain their original name, but the designation of hurricane becomes typhoon. In Japan and Vietnam, typhoons are simply numbered according to the sequence of their occurrence in the calendar year. Hence the third typhoon in a given year is simply "Typhoon No. 3".

See also

• Tropical cyclone

External links

• Unisys Data