The standby signal No 1 could be hoisted this morning as tropical storm Noul comes within 800 kilometers of Hong Kong. It could bring along heavy showers, says the observatory.
Tropical cyclone Noul, which was over the central and southern parts of the South China Sea, will move in the general direction of central Vietnam in the coming days, intensifying gradually.
The cyclone is expected to develop into a severe tropical storm at around 5pm today, and could further strengthen into a typhoon with maximum sustained winds up to 120 kilometers an hour tomorrow.
But according to current forecasts, scientific officer Tam Hiu-ching said, the observatory is not considering issuing any higher signals.
Meanwhile, the northeast monsoon will also gradually affect southern China.
Tam said the monsoon will not directly affect the cyclone, but the two weather conditions will simultaneously hit Hong Kong and bring heavy showers to the SAR.
"Under the combined effect of Noul and the northeast monsoon, it will be windy and increasingly showery with squally thunderstorms in Hong Kong later on Thursday and on Friday," the observatory warned.
At 4pm yesterday, the storm was centered about 610 kilometers southeast of the Paracel Islands, also known as the Xisha Islands. It was forecast to move west-northwest at about 15 kilometers an hour across the central and southern parts of the South China Sea.
The observatory also predicted that although it will be briefly sunny tomorrow, showers will increase later with squally thunderstorms. Winds will be moderate at first today, but will become strong on high ground and offshore later. There will also be swells today, it added.
Tam said heavy rains will continue to hit the city occasionally in the next two to three days because of the storm and the monsoon.
Meteorological organization Weather Underground of Hong Kong also stated on its social media page that Noul will not have a great impact on Hong Kong.
But it urged the public to stop all water activities as there could be a storm in the open sea.