page_title: 2011 Pacific typhoon season
section_title: Other systems
hierarchical_section_title: 2011 Pacific typhoon season / Systems / Other systems
caption_attribution_description: English: The Japan Meteorological Agency's Tropical Depression 21, on August 20, 2011
context_page_description: The 2011 Pacific typhoon season was a slightly below average season that produced a total of 21 named storms, 8 typhoons, and four super typhoons. This season was much more active than the previous season, although both seasons were below the Pacific typhoon average of 26. The season ran throughout 2011, though most tropical cyclone tend to develop between May and October. The season's first named storm, Aere, developed on May 7 while the season's last named storm, Washi dissipated on December 19.
  The season was also much deadlier and destructive than the previous season. Typhoon Muifa affected many countries during August. Tropical Storm Talas and Typhoon Roke made landfall over in Japan and were the most destructive since 2009. Typhoon Nesat was the most powerful to strike China since 2005. Tropical Storm Washi, a late but weak cyclone, affected southern Philippines and killed 2546 people.
  The scope of this article is limited to the Pacific Ocean to the north of the equator between 100th meridian east and the 180th meridian.
context_section_description: The following weak tropical depressions were also monitored by one or more of the warning centers, however they were either short lived or did not significantly develop further. On May 31, the JMA reported that a tropical depression had developed at the southern end of a shear line, about 420 km, (260 mi) to the southeast of Hong Kong, China. During that day as the depression moved towards the north-northeast, a trough of low pressure located over Hainan island and dry cold air wrapping into the depression's circulation inhibited further development of the depression. The depression then degenerated into an area of low pressure during the next day, before it dissipated during June 2,. On June 14, the JMA reported that a tropical depression had developed within an area of moderate vertical windshear, about 475 mi (764 km) to the southwest of Manila, Philippines. During that day the depression moved to the north-northwest, before the system dissipated during the next day. On July 16, the JMA reported that a tropical depression had developed about 225 km (140 mi) to the east of Hanoi in northern Vietnam, however it quickly weakened after interacting with land. In the morning of July 16, the Japan Meteorological Agency located in an area of low pressure on the land was upgraded to a tropical depression later on the same day. On July 17, the JMA downgraded the tropical depression to a low pressure. The Hong Kong Observatory only classified the tropical depression as a trough of low pressure is not to be ignored, while the Joint Typhoon Warning Center nor recognize this as a tropical disturbance. On August 19, a low pressure area developed east-northeast of Guam. Early on August 20, the system developed a broad area of low level circulation center and a good divergence aloft becoming more well defined. Later that day, the JMA upgraded the system to a tropical depression southeast of the Bonin Islands. On August 22, the system started interacting with an anticyclone and was exposed to a strong vertical wind shear, prompting the JMA to stop monitoring the system as a tropical depression, as the system dissipated to a remnant low. However, at midnight, the same day, the remnants regenerated, and the JMA started tracking the system as a tropical depression again, until it last appeared near Okinawa, Japan on August 25, as the system dissipated completely. On September 14, the JMA started to monitor a tropical depression that had developed about 720 km (450 mi) to the southeast of Taipei in Taiwan. During that day, the depression remained near stationary, before becoming stationary, the JMA then last noted the depression late on September 15, as it was absorbed by Typhoon Roke.
  On October 11, the JMA reported that a tropical depression had developed to the southeast of Hainan Island. Late on October 13, the system dissipated, just after making landfall over Vietnam. 
  On December 24, the JMA reported that a tropical depression had developed about 1,768 km (1,099 mi) to the southeast of Manila, in the Philippines. During that day, the depression moved towards the northwest before the JMA issued their final advisory on the system. The final tropical depression of the year then developed on December 31, about 340 km (210 mi) to the northeast of Kuala Lumpur, Malaysia. During that day the system moved slowly towards the northwest before it was last noted early the next day on January 1, 2012.
caption: A developing tropical depression on August 20, which failed to be a tropical storm in its lifecycle
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