The Hong Kong Observatory (HKO) said it will issue the Standby Signal No. 1 on Wednesday evening when a tropical cyclone over Luzon comes within 800 kilometers of the city.

The tropical cyclone is expected to move across the northeastern part of the South China Sea in the next couple of days, intensifying gradually as it moves in the general direction of eastern Guangdong, the HKO said in a weather bulletin issued at 12:05 pm on Wednesday.

Under the influence of the northeast monsoon, the tropical cyclone will then turn westwards, edging closer to the vicinity of the Pearl River Estuary, the HKO added.

“However, there are uncertainties in its landfall position and intensity. As its circulation is relatively small, the tropical cyclone will only bring significant impact to local weather when it gets relatively close to Hong Kong.”

Warning that there will be swells, the forecaster said the local weather will become unsettled on Friday under the influence of the tropical cyclone’s outer rainbands, and Hong Kong could see occasional heavy squally showers and thunderstorms over the weekend.

ALSO READ: Hong Kong charting the future of flood-fighting

The observatory said it will assess the need to issue higher tropical cyclone warning signals between Thursday and Friday, depending on the intensity of the tropical cyclone, the distance of its strong winds from Hong Kong and the change in local wind conditions.

Meanwhile, another tropical cyclone is expected to form over the western North Pacific to the east of the Philippines on Wednesday and Thursday, the HKO said in the same weather bulletin.

“The tropical cyclone will intensify significantly and move across the vicinity of Luzon Strait. It will enter the northern part of the South China Sea early next week and edge closer to the coast of southern China. ”

Under the influence of its extensive circulation of the tropical cyclone, the weather will deteriorate significantly over the region midweek next week, the HKO said.