South Korea has issued a nationwide heavy-rain warning as a low-pressure system brings intense precipitation and strong winds to the region [1].
This weather event poses a significant risk to infrastructure and public safety, particularly in mountainous and coastal zones where the terrain can amplify the severity of the storms.
According to Korea Meteorological Administration forecaster Gong Sang-min, the rain is the result of a low-pressure system that developed over the West Sea [1]. The precipitation is expected to continue until Thursday evening, May 21 [1]. Gong said strong rain accompanied by thunder, lightning, and gusts is expected overnight as cold air from the north collides with warm, humid air flowing from the southwest [1].
The impact of the storm varies by geography. Mountainous regions, including those in Jeju and Gangwon, are forecast to receive total rainfall of approximately 150 mm [1]. Inland areas are expected to see totals of about 100 mm [1]. In coastal areas, the intensity of the rainfall may reach roughly 30 mm per hour [1].
In addition to the heavy rain, officials are monitoring wind speeds, which are expected to exceed 15 m/s in some areas [1]. This atmospheric instability is also causing a sharp temperature shift, with some areas seeing a drop from above 33 °C to below 20 °C [1].
Forecasters said the collision of contrasting air masses, enhanced by topographic effects in the mountains, is the primary driver of the current instability [1]. Residents in coastal and mountainous zones are advised to remain vigilant as the system moves through the peninsula [1].
“Total rainfall forecast for mountainous regions about 150 mm”
The combination of high-intensity hourly rainfall and significant temperature drops suggests a volatile weather front. Because the most severe rain is concentrated in mountainous regions like Jeju and Gangwon, there is an increased risk of landslides and flash floods, which often occur when topographic lift enhances precipitation from colliding air masses.
