Taipei: Taiwan experienced its first full week of “extremely heavy” rain since 1998, as reported by Taiwan’s Central Weather Administration (CWA) on Monday.

According to Focus Taiwan, extremely heavy rain is characterized by a 24-hour accumulated rainfall exceeding 200 millimeters or a 3-hour accumulated rainfall surpassing 100 mm. This announcement came during a news conference where the CWA lifted the weeklong rain advisory, termed the “0728 Southwesterly Airflow Extremely Heavy Rain Incident.”

CWA’s director of the weather forecasting center, Chen Yi-liang, revealed that between July 28 and August 4, observation stations in central and southern Taiwan recorded over 200 mm of rain daily for the first time since 1998. The rain impacted 17 municipalities across Nantou, Yunlin, Chiayi, and Pingtung counties, as well as the cities of Tainan and Kaohsiung, which experienced “extremely torrential” rain with 24-hour accumulated rainfall exceeding 500 mm.

Chen further explained that in certain areas, the precipitation reached over 200 mm in three hours, resulting in torrential rain. This weather pattern persisted for five consecutive days in several locations, closely approaching the record set by Typhoon Morakot in 2009, which recorded 3,060 mm over five days in Chiayi County’s Alishan Township.

From July 28 to 2 p.m. on August 4, Kaohsiung’s Duona forest trail recorded the highest amount of rain at 2,873.5 mm, according to the CWA. Chen noted that the rain reached torrential and “extremely torrential” levels in two waves, initially from July 28 to 31 and subsequently from August 1 to 3.

Chen attributed the weeklong rain to fluctuations in the southwesterly airflow over the Bashi Channel. The most significant impact of the airflow was observed last Wednesday and Thursday when central and southern Taiwan received substantial rainfall. With the reduced likelihood of large-scale heavy rain, the CWA lifted the advisory at noon on Monday.