The Hong Kong Observatory on Thursday said it will issue the Standby Signal No 1 between noon and 3pm on Friday, as Tropical Cyclone Yinxing edges closer to Hong Kong.

Forecasters said the weather system will enter the SAR's 800-kilometre warning radius at around midnight on Friday, adding in a Facebook post that two more potential storms are forming over the Pacific Ocean.

The observatory said Yinxing’s circulation is relatively small, so it has to observe changes in intensity, local wind conditions, and how close it is from Hong Kong before it decides to issue a higher warning signal.

It added there will be a few showers over the coast of Guangdong during the weekend under the combined effects of Yinxing and the northeast monsoon.