Overview of Tropical Cyclones in July 2007

Overview of Tropical Cyclones in July 2007
(Tracks)

Three tropical cyclones formed over the western North Pacific and South China Sea in July 2007. Figure 2.1 shows the tracks of the tropical cyclones this month. As the sub-tropical ridge of high pressure was stronger than normal and covered a larger area in June and July this year, the development of tropical cyclones in the region was suppressed. Up to July this year, only five tropical cyclones occurred in the western North Pacific and South China Sea, about half of the mean total number of tropical cyclones for the same period in 1961-1990.

Toraji developed as a tropical depression over the South China Sea about 180 km south of Haikou on the morning of 4 July and moved generally northwestwards. Toraji crossed Hainan on that afternoon. It entered Beibu Wan on the morning of 5 July and then intensified into a tropical storm. Toraji made landfall near Dongxing at the coast of Guangxi that evening and weakened into an area of low pressure on the early morning of 6 July. Toraji brought heavy rain to parts of Guangxi. More than 6 700 hectares of farmland were affected and 378 houses collapsed, with another 946 houses damaged. The direct economic losses exceeded RMB$73 million.

Man-yi developed as a tropical depression over the western North Pacific about 1 250 km east-southeast of Yap on 7 July and moved generally northwestwards. It intensified into a tropical storm on 9 July, a severe tropical storm the next day and further into a typhoon on 11 July. Man-yi turned to a north-northwesterly track on 12 July. It turned further northwards on 13 July and passed about 30 km west of Okinawa in the same morning, where the mean sea level pressure fell below 942 hPa. Man-yi turned to move northeast on 14 July and made landfall over Kyushu, Japan. It then turned to move east-northeast on that night and skirted southern Shikoku. Man-yi weakened into a severe tropical storm on the morning of 15 July. It skirted the coastal waters to the south of Japan and weakened further into a tropical storm in the evening. Man-yi became an extratropical cyclone to the east of Japan on 16 July. According to press reports, Man-yi was the strongest typhoon on record to hit Japan in July since 1951. It brought torrential rain, flooding and landslides to Japan where at least 5 people were killed and 80 injured. More than 40 000 people had been evacuated. Fifteen houses were destroyed and about 1 500 flooded. Man-yi also cut off electricity supply to around 134 000 and 740 000 households respectively in Okinawa and Kyushu. Hundreds of flights were cancelled and train services were disrupted. Earlier, a Chinese freighter sank in high seas and storm force winds on 11 July when it was about 600 km northwest of Guam. Nine seamen were reported missing.

Usagi developed as a tropical depression over the western North Pacific about 1 440 km southeast of Iwo Jima on 28 July and moved generally westwards. It developed into a tropical storm on 29 July and then a severe tropical storm the next day when it turned to a northwesterly track. Usagi intensified further into a typhoon on 31 July and continued to move northwest.

Tracks of tropical cyclones in July 2007