Monsoon-like downpours expected in S. Korea from this weekend

South Korea can expect another round of heavy rain starting from the southern parts of the country this weekend, according to the Korea Meteorological Administration on Friday.

According to the KMA, a stationary front is forecast to form along the southern parts of the country from Saturday as warm, humid air from the southeast collides with dry air descending from the north.

Due to the stationary front, the southern parts of the country, as well as Jeju Island, can expect to see rainfall from Saturday. As a meso-scale low-pressure system develops along the stationary front, the KMA added that intense rainfall may be observed in the North and South Jeolla provinces through early Sunday.

In cities such as Gwangju, hourly rainfall reaching up to 30 to 50 millimeters could be observed over the two days.

“The heavy precipitation will be further fueled by the arrival of a low-level jet stream, supplying additional moisture to the developing stream,” said KMA official Lee Chang-jae during a press briefing Thursday.

On Saturday, the KMA anticipates rainfall accumulating up to 80 mm to fall in Gwangju, Busan, Ulsan and other cities in South Jeolla Province and South Gyeongsang Province, with heavily hit regions in Gwangju and South Jeolla Province possibly accumulating rainfall of up to 120 mm.

Up to 60 mm of accumulated rain may be observed in Daegu and other cities in North Gyeongsang Province, as well as North Jeolla Province and Jeju Island, while southern parts of South Chungcheong Province, as well as Daegu and southern parts of North Chungcheong Province, may see up to 20 mm of accumulated rain.

The KMA stated that rainfall will come to a temporary halt on Sunday, as the meso-scale low-pressure system moves away from the Korean Peninsula and pushes the stationary front toward the south of Jeju Island.

However, as the North Pacific high-pressure system begins to expand northward above the Korean Peninsula, the stationary front will be pushed back toward the southern parts of the country and Jeju Island from Aug. 11, bringing rain focused on the southern parts of the country.

From Aug. 12, rain clouds are expected to move up toward other parts of the country, bringing nationwide rain.

On Aug. 13 and 14, rainfall is expected in the central parts of the country, encompassing the Greater Seoul region, North and South Chungcheong provinces and Gangwon Province.

“As the North Pacific high-pressure system expands further to cover all of the Korean Peninsula, rain will cease to fall from Aug. 15, though heat wave advisories are expected to be issued in most parts of the country,” added Lee.

According to the KMA, the shifting stationary front and the repeated formation of low-pressure systems near its axis closely resemble the tail-end behavior of Korea’s monsoon season, typically seen in late July.

Rainfall amounts and their precise impact remain uncertain as different numerical forecast models offer varying scenarios, particularly regarding the strength and placement of the low-pressure system forming over the weekend.

While heavy rain alerts are highly likely for South Jeolla Province and South Gyeongsang Province over the weekend, the precise areas of concentrated rainfall are prone to shifting due to changing meteorological situations.