South Korea expects nationwide heavy monsoon rain to begin Friday night and continue through the weekend [4].
The shift in weather follows a brief lull in the monsoon season. The incoming rains pose a risk of flooding and instability across several provinces as a stationary front moves north across the peninsula.
Forecasters from the Korea Meteorological Administration (KMA) said that before the front arrives, Friday will be characterized by high humidity and temperatures around 30°C nationwide [1]. In Seoul, the morning temperature was 21°C, rising to 30°C during the day [2]. Some regions, including Yeoju in Gyeonggi Province and Gongju in Chungnam, may experience perceived temperatures as high as 33°C [3].
KMA forecaster Kang Hye-mi said that atmospheric instability will likely trigger scattered showers during the day on Friday. She said that the stationary front, which had been in a state of lull, will reactivate and move north starting Friday night [1].
The rain is expected to hit Jeju Island first, followed by the southern Chungcheong region [1]. The weather system will then expand to include the Seoul metropolitan area, and Gangwon Province [1]. Other southern and central parts of the country are also expected to fall under the rain band.
Reporter Jung Hye-yoon said that the stationary front's movement toward the Chungcheong region has already placed Jeju and southern areas under the monsoon influence [1]. The heavy rainfall is projected to persist through Saturday and Sunday [4].
Residents are advised to monitor local weather alerts as the front reactivates, as the combination of high humidity and sudden heavy downpours can create hazardous driving and walking conditions across the metropolitan areas.
“The stationary front, which had been in a state of lull, will reactivate and move north starting Friday night.”
The reactivation of a stationary front indicates a transition from a period of oppressive heat to the more volatile phase of the East Asian monsoon. Because the rain is moving from the south—starting in Jeju and progressing toward Seoul and Gangwon—local governments in the north have a short window to prepare drainage systems for the high-volume rainfall expected over the weekend.
