[1] Convection remained very fragmented until September 20, when the Japan Meteorological Agency (JMA) upgraded the low-pressure area to a tropical depression east-northeast of Guam early on that day.

[5][6] On September 22, although the structure remained asymmetric with a fully exposed LLCC under easterly moderate vertical wind shear, the system still intensified into a tropical storm late on the same day and received the name Dujuan from the JMA.

[9] Dujuan developed smaller vortices rotating around a larger circulation centroid with deep convection along the western periphery on September 23;[10] however, right after the storm entered the Philippine Area of Responsibility and was named Jenny by PAGASA, there was only one partially exposed LLCC within the consolidating structure in the afternoon, leading more model guidances to show a stairstep track vice a recurve scenario.

[11][12] When moving and organizing slowly on September 24, Dujuan was upgraded to a severe tropical storm early on that day, with an apparent eye revealed by a microwave imagery.

[13][14] Based on a ragged eye under decreasing vertical wind shear, both of the JTWC and then the JMA upgraded Dujuan to a typhoon early on September 25, as the system started to track northwestward along the southwestern periphery of a deep-layered subtropical ridge.

[15][16][17] Good divergent outflow as well as low vertical wind shear allowed Dujuan to intensify stably on September 26, yet dry air and subsidence were impacting the system at the same time, causing the western eyewall to break down.

[19] Due to sea surface temperatures of 29 °C and improved radial outflow enhanced by a microscale anticyclone aloft, the JTWC indicated that the typhoon with an enlarged 80 km (50 mi) eye embedded in the highly deep and symmetric core had one-minute maximum sustained winds at 230 km/h (140 mph) early on September 27, equivalent to Category 4 of the Saffir–Simpson hurricane wind scale.

[21][22] Soon, the eye shrunk quickly and became cloud-filled when the eyewall was interacting with the terrain of Taiwan, indicating a weakening trend from both the JMA and the JTWC.

[26][27] Dujuan made its second landfall over Xiuyu District, Putian of Fujian, China at around 08:50 CST (00:50 UTC) on September 29, shortly before the JTWC issued the final warning.

A group of people tried to fix a fallen fence at a construction site in Beitun District, Taichung; however, when a man was standing on a corrugated sheet, strong winds rolled them up.

[47][48] The most severe damage took place in Fujian Province where 400 homes collapsed, 31,000 hectares (77,000 acres) of farmland were flooded, and total economic losses reached ¥2.4 billion (US$377.5 million).