SEOUL-- Typhoon Chanthu is projected to move the closest to Jeju on Friday, the weather service said, warning driving rains will continue to drench the resort island and southern parts of the country until then.

The season's 14th typhoon was moving northward at a speed of 4 kph in the sea about 320 kilometers southwest of the city of Seogwipo as of 3 p.m. Wednesday, the Korea Meteorological Administration said. Its sustained maximum wind speed was clocked at 29 meters per second.

The midsized typhoon has already brought heavy downpours to the island, with some parts receiving as much as 700 mm of rain, triggering flash flooding and trapping cars on the roads.

Forecasters say the typhoon is expected to near the island Friday and gain intensity as it pivots eastward along the Korea Strait, a sea passage between South Korea and Japan.

Heavy rain and strong winds are expected to continue on Jeju and the southern regions, including the provinces of Jeolla and Gyeongsang, with the threat of flash floods, landslides and damage to structures.

On Thursday and Friday, up to 300 mm of rain could hit Jeju, and up to 120 mm of rainfall is expected in the South Jeolla and Gyeongsang provinces.

The Central Disaster and Safety Countermeasures Headquarters raised the alert level to "yellow," the second lowest of the four-color coded threat system.

The government asked the residents in affected areas to be on the lookout for typhoon alerts and stay vigilant. It also asked the provincial governments to thoroughly prepare for the arrival of the typhoon, especially when more people are expected to begin travel around the country for the upcoming Chuseok holiday.

To ensure the safety of children and teachers, the island's education office ordered all schools to cancel in-person classes Friday and asked parents and students to refrain from doing outdoor activities. On Thursday, schools are allowed to choose between in-person and remote instruction.

Source: Yonhap News Agency