Summer monsoon-like downpours expected to hit southern Korea on Tuesday

Torrential rain, comparable to peak-summer monsoon downpours, is forecast to hit the southern regions of Korea on Tuesday. The south coast and Jeju Island are expected to experience particularly heavy rainfall, driven by large moisture inflows.

“From Tuesday to Wednesday, heavy rain is expected nationwide due to a low-pressure system carrying large amounts of moisture and heat,” Lee Gwang-yeon, an analyst at the Korea Meteorological Administration (KMA), said during a weather briefing on Monday. “Jeju Island and southern coastal regions are expected to see rainfall intense enough to trigger heavy rain advisories.”

Rain began falling in parts of Jeju and southern coastal areas early Monday, with heavy rain advisories issued for Jeju's mountainous areas, according to the KMA. 

Rain is expected to spread nationwide beginning in the early hours of Tuesday before gradually tapering off in western regions by the early hours of Wednesday. Eastern coastal areas, however, could continue to see rain into the afternoon due to easterly winds.

Forecasters warned that unusually warm, moisture-laden air flowing in from the south is expected to rapidly intensify rain clouds even before the start of the summer monsoon season.

Mountainous areas of Jeju, southern coastal regions and areas near Mount Jiri are expected to see downpour-level rain of around 50 millimeters (2 inches) per hour. 

Other southern regions are also forecast to receive heavy rain of 20 to 30 millimeters per hour. Accumulated rainfall is expected to reach up to 150 millimeters in southern coastal regions and areas near Mount Jiri, while mountainous areas of Jeju could see more than 250 millimeters.

Central regions such as Seoul are forecast to receive 20 to 80 millimeters of rain accompanied by strong winds, thunder and lightning.

“High waves are expected at sea, while strong winds will affect inland areas,” Lee said. “[People] should take precautions for their safety and to prevent facility damage.”

No significant rainfall is expected for the time being, after the rain clears on Wednesday. The KMA’s midterm forecast predicts mostly clear weather nationwide through June 4, with daytime highs reaching around 30 degrees Celsius (86 degrees Fahrenheit).

Forecasters, however, warned that this summer’s rainy season could bring above-average rainfall beginning in June.

The KMA forecast precipitation levels in June and July to be generally above seasonal averages, particularly in southern regions, due to moisture carried by southerly winds.

Higher-than-usual sea surface temperatures around the Korean Peninsula are also increasing the likelihood of heavy rainfall, as warmer ocean waters generate larger amounts of moisture in the atmosphere.

“As June begins, the amount of moisture in the atmosphere increases, and rainfall tends to come in heavier bursts,” Woo Jin-kyu, a KMA official, said. “As summer approaches, people need to prepare for possible damage caused by heavy rain.”

This article was originally written in Korean and translated by a bilingual reporter with the help of generative AI tools. It was then edited by a native English-speaking editor. All AI-assisted translations are reviewed and refined by our newsroom.

BY CHON KWON-PIL [lee.jiwon10@joongang.co.kr]