Absence of Tropical Cyclone Genesis Over the Western North Pacific in July 2020 and Its Prediction by CFSv2

There were no TCs generated in July 2020 over the western North Pacific (WNP), which was first time this had happened during since 1980. This study attempts to understand cause of there having been 2020, and evaluates prediction skill for large-scale environmental conditions associated with TC genesis number (TCGN). Results show that main causes abnormal warming sea surface temperature (SST) Indian Ocean (NIO) Atlantic decrease SST from April May Niño4 region. The NIO can affect via SST–precipitation–wind feedback mechanism. Through interaction between tropical NIO, abnormally warm further strengthened impact on conditions. monthly difference (MD) index is significantly correlated TCGN July. Not only MD by affecting WNP anticyclone, but it also precipitation anomalies through a shift position Walker circulation. Besides, activity MJO certain absence 2020. Although CFSv2 successfully predict local TCGN, fails forecast