Heavy rain is forecasted overnight across most of the metropolitan area, as well as in South Chungcheong and North Jeolla, with hourly rainfall expected to reach a maximum of 50 to 80 mm. The hot and humid air moving north from the south is strongly colliding with the dry air descending from the north, bringing significant rainfall nationwide from the 3rd to the morning of the 5th.
As of 6 p.m. on the 3rd, it is already raining in most areas west of the Baekdu-daegan mountain range. 'Extreme heavy rain' is expected in various places. In the metropolitan area, rain may pour at a rate of 50 to 80 mm per hour in Seoul, Incheon, southern Gyeonggi, and northeastern Gyeonggi from the night of the 3rd to the morning of the 4th, while the remaining regions may see rainfall of 30 mm per hour.
In South Chungcheong and North Jeolla, hourly rainfall of 50 to 80 mm is expected from the night of the 3rd to the dawn of the 4th. Rainfall of 30 to 50 mm per hour is also expected in both regions on the morning of the 4th. In South Jeolla, areas along the southern coast and near Jirisan may experience rainfall of 50 to 80 mm per hour from the night of the 3rd to the morning of the 4th. The remaining regions will see rainfall of 30 to 50 mm per hour.
In the Yeongnam region, 30 to 50 mm of rain is expected between dawn and morning on the 4th in central and northern North Gyeongsang. Areas in Daegu and southern North Gyeongsang, as well as central and northern North Gyeongsang, are also expected to receive roughly 30 mm of rain each from dawn to afternoon on the 4th. In South Gyeongsang, areas along the southern coast and near Jirisan may see rainfall of 30 to 50 mm per hour late on the 3rd, followed by 50 to 80 mm per hour from dawn to morning on the 4th. The remaining areas are expected to receive 30 to 50 mm of rain between dawn and morning on the 4th, followed by around 30 mm of rain in the afternoon.
In Jeju, concentrated rainfall of 30 to 50 mm per hour is expected in the mountainous areas from the night of the 3rd to the dawn of the 4th. Rainfall of around 30 mm is also expected in Jeju's mountainous regions on the morning of the 4th.
By the morning of the 5th, total rainfall is expected to be 80 to 150 mm in Gwangju, South Jeolla, Busan, Ulsan, and South Gyeongsang (with a maximum of 250 mm in the southern coast and near Jirisan in South Gyeongsang, and over 200 mm in South Jeolla), and 50 to 100 mm in the metropolitan area, the western five islands, Daejeon, Sejong, South Chungcheong, and North Jeolla (with over 180 mm in southern South Chungcheong and North Jeolla, more than 150 mm in southeastern Gyeonggi, northeastern Gyeonggi, Daejeon, Sejong, and northern South Chungcheong, and over 120 mm in Seoul and Incheon).
In the inland and mountainous areas of Gangwon, as well as the central and southern eastern coast of Gangwon, North Chungcheong, Daegu, and North Gyeongsang, rainfall of 30 to 80 mm is expected (with areas in the central and southern inland of Gangwon, central and southern mountainous areas of Gangwon, North Chungcheong, and northern inland of North Gyeongsang expected to exceed 120 mm). In Jeju, except in the northern and western regions, rainfall of 20 to 60 mm is expected (with a maximum of 150 mm in the mountainous areas and over 100 mm in non-mountainous areas), while 10 to 40 mm is expected in the northern and western regions.
As heavy rain falls before recovery efforts are complete in areas that suffered flooding from heavy rain last month, significant damage may occur. Winds of about 55 km/h are also expected along the west coast, southern coast, and in Jeju, so precautions are necessary.
As the rain falls, the heatwave is expected to ease somewhat. The lowest temperatures in the morning on the 4th are predicted to be between 23 and 27 degrees, with the highest temperatures during the day forecasted to range from 29 to 34 degrees. The expected lowest and highest temperatures in major cities are as follows: Seoul 26 and 30 degrees, Incheon 25 and 29 degrees, Daejeon 25 and 32 degrees, Gwangju 26 and 33 degrees, Daegu 25 and 33 degrees, Ulsan 25 and 31 degrees, and Busan 26 and 31 degrees.