page_title: Tropical Storm Talas (2011)
section_title: Meteorological history
hierarchical_section_title: Tropical Storm Talas (2011) / Meteorological history
caption_attribution_description: English: Typhoon Talas on September 2, 2011
context_page_description: Severe Tropical Storm Talas, was an unusually large tropical cyclone that caused many deaths and severe damage to Japan. It was the 12th named storm and the 7th severe tropical storm of the 2011 Pacific typhoon season. Talas is known to have killed at least 82 people, and 16 more are still missing. The word Talas is a Filipino word meaning sharpness. It followed five months after Japan was hit by a large tsunami.
  Throughout Japan, Talas brought heavy rainfall leaving roads flooded. Extremely heavy rainfall of 66.5 millimeters per hour was observed, with rainfall of 69.0 mm in Yamanakako, Yamanashi, and 49.5 mm in Ichinoseki, Iwate which exceeded overall records for the entire month of September. Some 3,200 people were evacuated in 16 prefectures after extremely heavy rain. Some 700 houses were completely inundated by floods in eastern and western Japan and about 9,500 households in nine prefectures across the nation suffered power outages. More than 400 flights were cancelled leaving approximately 34,000 stranded.
  In post-analysis, the Japan Meteorological Agency downgraded Talas from a minimal typhoon to a severe tropical storm.
context_section_description: Late on August 22, an area of low pressure developed to the west of Guam. At midnight that day, the system became sufficiently well organized that the Japan Meteorological Agency (JMA) started tracking it as a tropical depression. On August 23, the system moved into an environment of low wind shear and warm sea surface temperatures prompting the JTWC to issue a Tropical Cyclone Formation Alert (TCFA) on it. By August 25, the system grew strong enough that the JMA upgraded it to a tropical storm, naming it Talas. Soon the system developed long and expansive convective banding along the eastern and south-western periphery of the broad low level circulation center, similar to a monsoonal depression. The JTWC initiated advisories on the system, designating it with 15W. The JTWC originally anticipated a fujiwhara effect of Typhoon Nanmadol, a stronger tropical cyclone to the west of Talas.
  However, the two cyclones moved far away from each other with at least 1,000 nautical miles (1,900 km; 1,200 mi) of distance between them. This prompted the JTWC to change its forecast on the system, from turning west and interacting with Nanmadol, to continuously move north and intensify into a typhoon. This prompted the JMA to upgrade Talas to a severe tropical storm with winds of 50 knots (93 km/h; 58 mph). Multiple competitive steering ridges caused Talas to move in a poleward direction with stronger winds in the periphery and weaker winds near the center. A tropical upper tropospheric trough (TUTT) caused subsidance in the atmosphere which caused a disturbance in the outflow towards the northwest of the system. However, another TUTT cell to the northeast opened an outflow channel which kept Talas from being destroyed by shear. Talas was very loosely organized with a relatively open circulation center and very low consolidation around the core. Convection was also displaced towards the periphery and stronger wind shear kept Talas from strengthening.
  Talas, being located in a very weak steering environment hardly moved in 24 hours and was effectively trapped between strong subtropical ridges and an anticyclone. Talas failed to strengthen for a very long time and remained loosely organized with all the convection located in the periphery. Early on August 28, Talas started to strengthen after a whole day in dry winds. The low-level circulation center started to get consolidated with deep convective bands wrapping into it. Talas was expected to make landfall over central Japan with strong winds. Talas then moved into an environment favorable for slow development, with moist winds and significantly warm sea surface temperatures. The center became well organized with convective bands tightly wrapped into it. Wind shear decreased and the center was wrapped with more tightly curved banding. The JTWC reported that there was more confidence in the strength and position of the system. They JTWC reported that they were expecting a peak intensity of 90 knots (170 km/h; 100 mph).
  Soon, the subtropical ridge to the west of the storm weakened and the subtropical ridge to the east of the system pushed Talas to the west. As a result, Talas accelerated towards the west maintaining strength and outflow. An upper-level cyclone over the system suppressed the convection and kept it from reaching the center. Therefore, Talas remained weak and did not strengthen further. Convection never managed to consolidate the center and convective banding remained well away from the fully exposed low-level circulation center. Convective banding completely encircled the LLCC but never managed to consolidate over the LLCC because of the strong upper-lever cyclone over the storm. Talas was being steered by a mid-level anticyclone, a part of the developing omega block. On September 1, Talas developed a large annulus of nearly 110 nautical miles (200 km; 130 mi) in diameter with multiple weak circulations cyclonically rotating around a centroid within the center. Fragmented deep convective banding broadly wrapped the low-level circulation center with an upper-level cyclone over
caption: Severe Tropical Storm Talas approaching Japan on September 2
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