With a massive rain band 900 kilometres wide, combined with seasonal monsoon rains, the storm could bring heavy to intense rains that could set off landslides and flash floods, Philippine state forecaster Meno Mendoza said.
Cathay Pacific Airways Ltd. encouraged passengers travelling this weekend to and from Hong Kong to re-book and the airline will waive the fees.
The Meteorological and Geophysical Bureau (SMG) told Macau News Agency (MNA) that current predictions indicate Typhoon Signal No.8 or No.10 could be hoisted between September 15 (Saturday) night and September 16 (Sunday) due to Typhoon Mangkhut.
Thousands are evacuating seaside areas of the northern tip of the main Philippine island of Luzon, where the storm is expected to make landfall early Saturday.
"Even further strengthening is expected with Mangkhut as it moves westward toward land", said AccuWeather Senior Meteorologist Adam Douty, adding, "If sustained wind speeds of 220 km/h are reached, Mangkhut will not only be a super typhoon, but also equivalent to a Category 5 hurricane in the Atlantic and eastern Pacific". Its high winds and torrential rains could cause widespread damage to islands and coastal areas.
While Mangkhut is now stronger than Hato -- also known as Tropical Storm Isang -- or Haima it is likely to decrease in strength as it nears southern China, particularly if it crosses land over northern Luzon, which will slow the storm, according to Guy, the meteorologist.More news: Pope To Meet With U.S. Church Leaders Over Clergy Sex Abuse
The most powerful typhoon to threaten the Philippines this year roared toward the country's north on Wednesday, prompting officials to order precautionary evacuations and closures of schools and offices, and farmers to quickly harvest their crops to reduce damage. The Philippines has been trying to cope with rice shortages.
President Rodrigo Duterte adjusted his schedule on Thursday so he can lead the command conference on the government's preparation for Typhoon Ompong. In 2013, Super Typhoon Haiyan killed more than 6,300 people in the Philippines.
The storm approaches the Phillipines as hurricane Florence will make landfall on the south-east coast of the U.S. later this week.
Should typhoon Mangkhut follow its projected path, Taiwan and Hong Kong are next in line to be hit.
An average of 20 typhoons and storms batter the country each year, leading to hundreds of deaths.