TAIPEI (TVBS News) — The periphery of Typhoon Co-May (竹節草颱風) and a southwest airflow caused significant rainfall in Taiwan's central and southern regions Tuesday (July 29). The southern areas and central mountains face a high probability of experiencing torrential rain across the island. Cheng Ming-dean (鄭明典), former administrator of the Central Weather Administration (CWA, 氣象局), Taiwan's national weather service, explained the meteorological situation on Facebook.
Cheng noted that a monsoon wind band extends from the northern Indian Ocean to the northwestern Pacific, bringing substantial moisture to the region. The strong winds within this monsoon system pass through the Bashi Channel and northern Philippines, forming the southwest airflow affecting Taiwan. He added that the rain in northern Taiwan is directly influenced by the typhoon's peripheral circulation patterns.
Cheng highlighted another monsoon low-pressure circulation outside the typhoon's circulation, adding complexity to the weather pattern. He attributed yesterday's rain disaster in the south to the convergence of the monsoon low-pressure circulation and monsoon airflow, creating a regional southwest airflow. Cheng also warned of the trend of convection developing along the southern coast last night. He stated that the main strong convection band did not move inland, and the airflow increasingly failed to cross the mountain, leading to enhanced mountain-circling movements of unstable airflow in the convergence zone. ◼