In 2020, the long-persisting Meiyu season around the Yangtze River (YR) started in early-June and ended in mid­–late-July. Its accumulated precipitation amount broke the record since 1961. We showed that the sequential warm and cold Meiyu front regulated by the North Atlantic Oscillation was responsible for this record-breaking Meiyu rainfall. From 11 to 25 June with the positive NAO, the interaction between South Asian High (SAH) and western Pacific subtropical high maintained a warm front to strengthen the rainband north of YR. Afterward, the coupling between SAH and mid-latitude Mongolian Cyclone induced a cold front, which retreated the rainband to the south of YR from 30 June to 13 July with the negative NAO. Although the ECMWF S2S successfully predicted the warm-front-related Meiyu rainband, it failed to forecast the Meiyu rainband in the cold-front period, suggesting a great challenge of the S2S forecast on Meiyu rainfall.