As tropical storm Chanthu continues to move closer to Hong Kong, the Hong Kong Observatory issued a tropical cyclone bulletin on Wednesday afternoon, raising the warning to Strong Wind Signal No. 3.

This means that winds with mean speeds of 41 to 62 kilometers per hour are expected, said the Hong Kong Observatory.

At 5 p.m. HK time (0900 GMT), Chanthu was estimated to be about 410 km south-southwest of Hong Kong and is forecast to move northwest at about 12 km per hour, edging closer to the coast of western Guangdong, said the bulletin.

The outer rainbands of Chanthu are affecting Hong Kong. As Chanthu continues to move closer, winds will strengthen overnight, it said.

On Wednesday afternoon, the maximum sustained winds recorded at Tate's Cairn and Cheung Chau in southwest Hong Kong were 46 and 36 km per hour, respectively, it said.

The Observatory also issued several precautionary announcements, calling on residents to protect home or property, clear storm water drains, stay away from the shoreline, avoid walking or working in areas exposed to gales and squalls and secure all scaffoldings.

Small craft owners should now complete arrangements for the safety of their boats, while fishing vessels not yet in typhoon shelters should seek shelter without delay, it added.

With the effect of Strong Wind Signal No. 3, the Home Affairs Department of the city's government has activated a public inquiry service hotline to provide a round-the-clock inquiry service to the public on the tropical cyclone.

The Education Bureau ordered that classes of kindergartens, schools for children with physical disability and schools for children with intellectual disability should be suspended in the day.

"These schools, however, should keep their premises open and implement contingency measures to look after arriving students. They should ensure that conditions are safe before students are allowed to return home," the Education Bureau said in a special announcement.

The Tourism Commission of the HKSAR government also announced that an entertainment program "A Symphony of Lights", scheduled for Wednesday night, would be suspended.

Chanthu is expected to make landfall in south China's Guangdong and Hainan provinces on Thursday, the Chinese National Meteorological Center (NMC) said earlier in the day.

Chanthu, the third tropical storm of the year, which strengthened early Wednesday, is forecast to move northwestward at a speed of 15 km per hour, said the NMC.