The southern coastal region is forecast to be hit by heavy downpours and strong winds Monday, as Typhoon Omais is projected to make landfall there later at night, the national weather agency said.

The typhoon was located at some 500 kilometers southwest off Jeju as of 9 a.m. and advancing slowly toward the Korean Peninsula at 31 kph, the Korea Meteorological Administration (KMA) said.

It is projected to pass the southern resort island of Jeju at night and be downgraded to an extratropical cyclone after making landfall around midnight.The typhoon is forecast to bring torrential downpours of more than 70 millimeters per hour and ferocious winds to Jeju during the day, with an accumulated 100-300 mm of rainfall until Tuesday.

A low pressure system, which is also approaching the island, is expected to bring additional rainfall accompanied by thunder and lightning.

The southern port city of Busan is expected to be hit with heavy rain of 70 mm per hour and bring 30 meter-per-second wind gusts, with some areas receiving as much as 400 mm of rain until Tuesday.

The weather service warned strong winds and a storm surge could disrupt public transportation to the island until Tuesday, and advised the local governments, and especially residents in low-lying areas, to thoroughly prepare for the storm.

As of 11 a.m., 28 flights flying to and from the island were grounded and the Korea Airports Corp. expected more flights to be canceled in the afternoon due to the typhoon. (Yonhap)