The Hong Kong Observatory may issue the No 1 standby signal on Tuesday as Tropical Cyclone Yagi is expected to enter within 800km (500 miles) of the city.
“Whether a higher Tropical Cyclone Warning Signal to be issued depends on the intensity, circulation size of Yagi and its distance from Hong Kong,” the weather forecaster said on Monday.
The Observatory said it would consider issuing the signal between Tuesday afternoon and night.
It added that Yagi was centred about 190km east of Manila as of 10am and was expected to move north-northwest at about 18km/h (11mph) towards the vicinity of the northern part of Luzon.
It is set to edge closer to the coast of southern China after entering within 800km of Hong Kong on Tuesday.
The forecaster said Yagi had “a higher chance” to move towards the vicinity of the western part of Guangdong and Hainan Island and further intensify.
According to the storm tracker, Yagi will become a typhoon on Thursday, before further strengthening to a severe typhoon and entering within 400km of the city on Friday.