With heat wave warnings in effect nationwide, heavy rain will continue from Sunday. After it stops, the heat will persist again.
According to the Korea Meteorological Administration on the 2nd, as warm and humid air begins to flow into the country on the 3rd, rain is expected to start in the western regions, becoming heavy from the night of the 3rd to the afternoon of the 4th. In the metropolitan area, Chungcheong, Honam, and the southern coast of Gyeongnam, there will be times when 'extreme downpours' of 50 to 80 mm per hour occur.
Currently, Typhoon Krosa, the 9th typhoon, is passing through the northeast sea of Tokyo, Japan, while the tropical depression No. 20 located south of Kagoshima is moving northeast, weakening the northern Pacific high pressure that has covered Korea and caused the heat, which is now being carried away by the westerlies.
After the 3rd, the main body of the northern Pacific high pressure will expand its influence southward into Korea, bringing in large amounts of moisture left by Typhoon Komae to the south. The temperate low pressure weakened from Komae will also pass through Korea from west to east, additionally drawing in substantial moisture over the Yellow Sea.
Due to sustained heat waves, the sea surface temperature in the Yellow Sea is around 30 degrees Celsius, which is 1 to 3 degrees higher than usual, resulting in a significantly high amount of moisture supplied to the atmosphere from the Yellow Sea.
From the 3rd to the 4th, the total precipitation is expected to be 50 to 150 mm in Gwangju, Jeonnam, Busan, Ulsan, and Gyeongnam (more than 200 mm on the Jeonnam coast, and more than 180 mm on the Busan and southern Gyeongnam coasts and near Jirisan), 50 to 100 mm in the metropolitan area, Daejeon, Sejong, Chungnam, and Jeonbuk (more than 150 mm), and 30 to 100 mm in Jeju (excluding the northern region, with up to 120 mm in mountainous areas).
In the Yellow Sea 5 islands, Gangwon inland, Gangwon mountainous areas, Chungbuk, Daegu, and Gyeongbuk, there will be 30 to 80 mm of rain (with more than 100 mm in northern inland areas of Gangwon, Gangwon mountainous areas, Chungbuk, and northern Gyeongbuk), and 20 to 60 mm on Ulleungdo and Dokdo. The eastern coast of Gangwon and northern Jeju will receive 10 to 40 mm of precipitation.
The problem is that another round of heavy rain is expected on the 6th and 7th. During this time, a 'band-shaped' rain cloud that brings torrential downpours is expected to sweep through Korea from the central region to the southern region.
Despite the heavy rain, the heat will not dissipate. In areas where rain falls heavily, heat wave warnings may be lifted briefly, but once the rain stops, temperatures will rise high enough to issue heat wave warnings again. As warm and humid air continues to flow in, the feels-like temperature will remain high, along with persistent tropical nights.