What typhoon struck China in 2012 approached within 800 km of Hong Kong and posed a threat of deteriorating conditions in Hong Kong?
Hong Kong tropical cyclone warning signals: The Hong Kong tropical cyclone warning signals (), or informally typhoon signals (, literally, "wind balls"), are a set of signals used to indicate the threat or effects of a tropical cyclone. Hong Kong tropical cyclone warning signals:  The Hong Kong Observatory issues the warning signal if a tropical cyclone approaches within 800 km of Hong Kong and poses a threat of deteriorating conditions in Hong Kong.
i don't know