Historical Record of November 2024 Typhoons in Hong Kong: Observations and Forecasts of Yinxing, Toraji, and Man-yi

In November 2024, four tropical cyclones (TCs) developed consecutively over the South China Sea and the western North Pacific. This is the first time that the simultaneous occurrence of four TCs was documented in this ocean basin. The climatological background for this phenomenon was analysed in this paper. The observational aspects of the three TCs affecting Hong Kong have been analysed using dropsonde data, weather buoy observations (particularly change in sea temperatures in the upper ocean), and radar imageries (in the region of gale force winds around Hong Kong). The forecasting aspects of the TCs are also discussed. In particular, the performance of artificial intelligence models in forecasting TC tracks and intensities has been reviewed. The first time real-time, operational use of an atmosphere-wave-ocean coupled model was discussed. The significant wave height forecasts during the passage of the three TCs over the South China Sea was also analysed using the Operational Marine Forecasting System of the Hong Kong Observatory (HKO) in comparison with the weather buoy observations of this basin. This paper serves to document the climatological, observational and forecasting aspects of this unprecedented case of simultaneous occurrence of four TCs in the fall season over the South China Sea and western North Pacific for future reference. © 2025 The authors.