Study of Extreme Cold Surges in Hong Kong

Temperatures over Hong Kong have shown a marked increasing trend since the 1970s due to global warming and urbanization, but outbreaks of intense winter monsoon can bring very low temperatures in at times. This study aims establishing criteria extreme cold surges that suit climatological characteristics Kong. Surges this were selected through percentile ranking three weather attributes each event: lowest temperature, largest temperature drop maximum sustained wind speed. Out 152 events 1991–2020, only four significant 1991, 1993, 2010 2016 met most 10th concurrently could be classified operationally as “extreme surge”. Very (at or below 7.0 °C), least 8.0 °C two days gale force speed above 17.5 m/s) recorded all surges. The results classification are illustrated by cases. As ensemble products some numerical prediction models tend stable indication extremity events, potential applications cross-referencing forecast actual operational forecasting also discussed.