The observatory will issue Standby Signal No. 1 at 12.20pm on Monday and consider upgrading it to a T3 warning between 8 and 10pm as Super Typhoon Ragasa thunders towards southern China.

Forecasters said in a statement on Monday that Ragasa – estimated to be packing maximum sustained winds of about 230 kilometres per hour near its centre – will “pose a considerable threat to the coast of Guangdong.”

The observatory noted that the storm covers an extensive area, and its speed of movement is “relatively high.” As of Monday at 8am, Ragasa was moving at around 22 kph across the Luzon Strait.

The weather service in the Philippines expect the storm to make landfall on the sparsely populated Batanes or Babuyan islands by early afternoon.

“With Ragasa gradually edging closer, local winds will strengthen gradually [on Tuesday], and weather will deteriorate rapidly later,” the observatorysaid.

“The Observatory will consider issuing the Strong Wind Signal, No 3 between 8 pm and 10 pm [on Monday].

“It is expected that gale to storm force winds will prevail locally on Wednesday, and winds may reach hurricane force offshore and on high ground.”

Hurricane-force winds have a speed of at least 118 km/h, while gale- and storm-force winds cover a range between 63 and 117 km/h.

Forecasters say the storm will bring heavy squally showers and thunderstorms, along with a significant storm surge that may bring sea levels similar to those seen in 2018's powerful Typhoon Mangkhut and Typhoon Hato a year before that.

The government has said it would make an announcement on Monday regarding school arrangements for the following day.