Super Typhoon Hato — Observations, Forecasting and Warning

Super Typhoon Hato affected the south China coast in late August 2017. In Hong Kong, the Hurricane Signal No. 10 was issued during the passage of Hato, the first time this highest tropical cyclone warning was issued since Severe Typhoon Vicente in July 2012. Hato intensified rapidly after entering the northeastern part of the South China Sea and attained super typhoon intensity briefly prior to landfall over the sea areas south of Hong Kong, the first time a super typhoon hit the territory since Hope in 1979.

The hurricane force winds and severe storm surge of Hato led to coastal flooding and severe damages over the Pearl River Delta region. In Hong Kong, as the approach of Hato coincided with the astronomical high tide, the aggregated effect resulted in unusually high water levels in many places. The water level at Quarry Bay inside the Victoria Harbour reached a maximum of 3.57 mCD (metres above Chart Datum), the second highest since records began in 1954, and second only to the record high of 3.96 mCD set by Super Typhoon Wanda in 1962.

The presentation will focus on the meteorological observations of Hato, including conventional measurement as well as special observations from remote-sensing meteorological equipment such as wind profiler, microwave radiometer, acoustic radar, wind LIDAR and water vapour LIDAR, and many of the observations made are the first of their kinds within the boundary layer of a super typhoon in Hong Kong. The performance of the weather forecasts and warnings issued by the Hong Kong Observatory in the case of Hato will be reviewed. Discussion will also cover the communication strategy adopted, particularly in raising public awareness and preparedness of the anticipated storm surge threats over the vulnerable areas in Hong Kong. Moreover, the meteorological services for the aviation sector to allow for the orderly recovery of air traffic following the cancellation of more than 480 flights will be briefly discussed.