The Observatory on Monday said the chance of issuing a tropical cyclone warning signal is relatively low unless Narra edges closer to the vicinity of the Pearl River estuary.
The storm is expected to linger in the vicinity of Beibu Wan on Monday, and turn northeastwards gradually on Tuesday, edging closer to the western coast of Leizhou peninsula in the next couple of days.
The weather forecaster says Narra is expected to maintain quite some distance from Hong Kong.
Apart from Narra, the Observatory said the direct threat from another tropical cyclone Gaenari to Hong Kong is not high, as it is expected to dissipate gradually in the vicinity of Taiwan Strait on Monday.