Heavy rainfall events (HREs) have great socioeconomic impacts around the world and cause deadly and destructive disasters. China is located in the East Asia monsoon area and frequently susceptible to heavy rainfall and flooding extremes (Cao & Gao, 2007;H. Li et al., 2017). Studies on HREs have always been concerned widely and highly (Chen et al., 2012;Junker et al., 1999).Although HREs generally have a short-lived and localized nature (Jo et al., 2020), they are actually modulated by synoptic-scale systems, such as the western Pacific subtropical high (WPSH, Ding & Chan, 2005), tropical cyclone (TC, also known as typhoon, Ross & Kurihara, 1995), and southeasterly moisture transport produced by their interaction (Y. Nie & Sun, 2022). H. Wang et al. (2021) divided the persistent HREs over the Yangtze-Huaihe River Valley during 1981-2020 into three types according to pattern correlation. They emphasized that the WPSH and TC play significant roles in persistent HREs. Y. Wang et al. ( 2009) performed numerical sensitivity experiments to suggest that Typhoon Songda (2004) enhanced the transport of moisture to the heavy rainfall region through the outer circulation and was responsible for >90% of the precipitation in Japan. Many studies have revealed that when a TC approaches the WPSH, the pressure gradient between them increases rapidly, establishing or strengthening the low-level easterly jet, which is beneficial to transport water vapor toward the heavy rainfall region (Schumacher et al., 2011).