What typhoon struck China in 2012 approached within 800 km of Hong Kong and posed a threat of deteriorating conditions in Hong Kong?
Typhoon Vicente: Typhoon Vicente, known in the Philippines as Tropical Depression Ferdie, was regarded as the most powerful storm to strike southern China in recent years, as it made landfall as a powerful category 4 equivalent-typhoon. 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.
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