The Hong Kong Observatory on Tuesday said the Strong Wind Signal No 3 would remain in force until at least 6pm.
Kok Mang-hin, a senior scientific officer, said the forecaster might issue higher signals depending on changes in the intensity of the nearby tropical depression, and variations in local wind strength. He said the observatory would continue to monitor the movement of the storm.
Kok said that at around 12pm, the tropical depression was estimated to be about 580 kilometres south-southwest of Hong Kong and was forecast to move north at about 80km/h towards western Guangdong and Hainan Island, intensifying gradually.
He said that the broad outer rain bands associated with the storm were affecting the northeastern part of the South China Sea and the coast of Guangdong, and could affect the SAR.
Heavy showers and thunderstorms were forecast for the rest of the day and on Wednesday.
Kok warned that high winds and prolonged heavy rain would increase the risk of flooding, and urged people to carry out the necessary flood prevention measures.
He advised the public to be alert, allow more time for travelling and avoid water sports as seas would be rough.