The season's fifth typhoon is likely to unleash up to 50 millimeters of rain per hour through Saturday in some areas, according to the Korea Meteorological Administration (KMA).

"The typhoon, though small in scale, could bring extreme and unusual rainfall to southern regions and Jeju Island," a KMA official said. "Full-fledged preparedness is needed."

The national weather agency forecast southern coastal regions and Jeju Island to receive 150-300mm of rain through Saturday, with 500-700mm expected for some mountainous areas.

Precipitation will be 50-150 mm in the southern provinces of Jeolla and Gyeongsang and the northeastern province of Gangwon and 10-70 mm in other parts of the country, it said. (Yonhap)