The Korea Meteorological Administration issued a heavy-rain and strong-wind advisory for northern Gyeonggi Province and the Seoul metropolitan area today [1, 2].

These warnings signal a high risk of flash flooding and structural damage in densely populated regions of the capital. The convergence of tropical moisture and cold air creates a volatile environment for the northern provinces.

Weather officials forecast that northern Gyeonggi Province could receive up to 120mm of rain [1]. Other areas in the Seoul metropolitan area are expected to see between 30 and 100mm [1], while northern Gangwon Province may receive 100mm or more [1].

The storm is not limited to precipitation. The administration warned of strong winds reaching speeds of 20 m/s or higher along the central coast and inland areas [2].

According to the agency, the weather pattern is driven by tropical moisture left behind by Typhoon Bob after the storm passed over China [1, 2]. This moisture is now colliding with cold air and mountainous terrain, triggering the intense precipitation.

Rain began falling this morning across the capital region and Chungnam [1, 2]. However, the most severe conditions are expected later today. The heaviest rain is forecast to fall tonight between 20:00 and 24:00 [1].

"Today tonight, heavy rain will pour, centered on northern Gyeonggi, northern Gangwon, and the metropolitan area," a YTN news anchor said [1].

Reporter Ko Han-seok said that the forecasts for the Seoul metropolitan area range from 30 to 100mm, with northern Gyeonggi seeing the highest levels [1]. The anchor said that the influence of the tropical moisture from Typhoon Bob has put both heavy rain and strong winds on high alert [1].

“Northern Gyeonggi Province could see up to 120mm of rain and strong winds tonight.”

This weather event demonstrates the delayed impact of tropical cyclones, where the moisture remnants of a typhoon can cause significant hydrological stress even after the storm center has exited the region. The combination of high wind speeds and concentrated rainfall in the mountainous northern provinces increases the likelihood of landslides and urban flooding in the Seoul metropolitan area.