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Typhoon Usagi, known in the Philippines as Typhoon Odette, was a violent tropical cyclone which affected Taiwan, the Philippines, China, and Hong Kong in September 2013. , which means the constellation Lepus or literally ''rabbit'' in Japanese, was the fourth typhoon and the nineteenth tropical storm in the basin. Developing into a tropical storm east of the Philippines late on September 16, Usagi began explosive intensification on September 19 and ultimately became a violent and large typhoon. Afterwards, the system weakened slowly, crossed the Bashi Channel on September 21, and made landfall over Guangdong, China on September 22. ==Meteorological history== Early on September 16, 2013 the Japan Meteorological Agency (JMA) started to monitor a tropical depression, that had developed within an area of low-moderate vertical windshear about to the east of Manilla in the Philippines. During that day as the systems low level circulation centre became better defined, the Joint Typhoon Warning Center (JTWC) issued a Tropical Cyclone Formation Alert on the system while the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) named the system ''Odette''. Late on the same day, JMA upgraded the system to a tropical storm and named it ''Usagi''; at the same time, The JTWC upgraded it to a tropical depression ''17W'', owing to a tropical upper tropospheric trough cell located to the east in association with an anticyclone enhancing the outflow in the eastern and southern quadrants. On September 17, The JTWC upgraded Usagi to a tropical storm, as the system continued to consolidate and wrap tighter when slowly tracking westward along the extreme southern periphery of the subtropical ridge. Early on September 18, JMA upgraded Usagi to a severe tropical storm; at noon, both JMA and The JTWC upgraded Usagi to a typhoon, as deep convection had completely wrapped around a developing eye with radial outflow and low vertical wind shear. On September 19, Usagi began explosive intensification and formed a round eye; as the result, The JTWC upgraded Usagi to a category 5 equivalent-super typhoon on the Saffir–Simpson hurricane wind scale at noon. However, in a post season reanalysis, it was concluded that Usagi peaked with winds at 155 mph, making it a strong category four on the Saffir-Simpson hurricane wind scale.〔(【引用サイトリンク】publisher=United states navy )〕 At 18Z, Usagi reached its peak intensity with 10-minute maximum sustained winds at 205 km/h (125 mph) and the atmospheric pressure at On September 20, Usagi began an eyewall replacement cycle with a inner eyewall and a outer eyewall separated by a clearly defined moat, as well as the system began to weaken late on the same day due to land interaction between Taiwan and Luzon. When Usagi had ventured into the Bashi Channel early on September 21, the JTWC downgraded it to a typhoon for convection becoming more shallow. However, sustained winds up to and the atmospheric pressure at were recorded on Basco, Batanes when the eyewall passed the municipality.〔(【引用サイトリンク】url=http://www.westernpacificweather.com/2013/09/21/violent-super-typhoon-usagi-odette-saturday-afternoon-update/ )〕 Later, as the eyewall replacement cycle had completed, the eye became cloud-filled, although the environment remained favourable with excellent radial outflow and low vertical wind shear. On September 22, Usagi’s eye resurged, allowing the typhoon maintaining intensity when approaching the coast of China. At 11:40 UTC (19:40 CST), Typhoon Usagi made landfall over Shanwei, Guangdong, China with 10-minute maximum sustained winds at 85 knots (155 km/h, 100 mph) and the atmospheric pressure at .〔(【引用サイトリンク】url=http://www.bbc.co.uk/zhongwen/simp/china/2013/09/130923_usagi_guangdong.shtml )〕 Soon, the JTWC issued its final warning on Usagi, while the JMA downgraded it to a severe tropical storm at 18Z. On September 23, the JMA downgraded the Usagi to a tropical storm and later a tropical depression in Guangxi. The system subsequently dissipated during September 24. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Typhoon Usagi (2013)」の詳細全文を読む スポンサード リンク
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