The Strong Wind Signal, No. 3 was issued at 10.40 am on Saturday and will remain in force for most of today.
The weather watchdog said the severe tropical storm Trami had intensified into a typhoon this morning, skirting to the south of Hong Kong at a distance of about 500 kilometers or more.
At 3 pm, Typhoon Trami was estimated to be about 620 kilometers south-southwest of Hong Kong and is forecast to move west at about 18 kilometers per hour towards the seas south of Hainan Island.
Under the combined effect of Trami and the northeast monsoon, the associated strong winds are gradually affecting the vicinity of the Pearl River Estuary.
The Observatory said that with Trami departing, local winds will weaken gradually tonight to tomorrow (Oct 27) morning and will consider issuing the Standby Signal, No. 1 then.
(Updated at 3.07 pm)
