On the 8th, monsoon rain will fall in many parts of the country. As the stationary front positioned near the central region moves north and south, most areas nationwide will come under the influence of rain clouds.
From the previous night, considerable rain poured down mainly in the capital area, inland Gangwon, and South Chungcheong. From 9 p.m. the previous day to 8 a.m. this day, cumulative rainfall was tallied at 47.4 mm on Baengnyeong Island in Ongjin County, Incheon, 37.0 mm in Gangseo District, Seoul, and 36.0 mm in Jangheung-myeon, Yangju, Gyeonggi. Along the northwestern coast of Incheon and northern Gyeonggi, 20–50 mm fell, while the rest of the capital area, inland Gangwon, and South Chungcheong saw around 5–30 mm.
This rain will continue nationwide through the night of the 9th. In the capital area and inland and mountainous Gangwon, rain is expected to persist through the morning of the 10th.
Expected rainfall through the 9th is 80–150 mm in Chungcheong and North Jeolla. Some areas could see more than 200 mm. In the capital area; inland and mountainous Gangwon; and central and northern North Gyeongsang, 50–100 mm is forecast, with some parts of the capital area; central and southern inland Gangwon; and central and northern North Gyeongsang likely to see more than 150 mm.
In northwestern South Jeolla, 30–80 mm is expected, with some areas seeing more than 100 mm. The five islands in the West Sea and Daegu and southern North Gyeongsang will see 20–60 mm, and most of Gwangju and South Jeolla is expected to get 10–40 mm. The east coast of Gangwon will see 5–50 mm; western inland South Gyeongsang and Ulleung Island and Dokdo will see 5–40 mm; Jeju's mountains will see 5–20 mm; and areas of Jeju excluding the mountains are forecast to see around 5 mm.
The five islands in the West Sea, the capital area, and inland and mountainous Gangwon will get additional rain on the 10th. The five islands in the West Sea are likely to see 20–60 mm, and the capital area and inland and mountainous Gangwon are likely to see an additional 5–40 mm.
Chungcheong and North Jeolla are expected to see heavy rain of 30–50 mm per hour from this evening into the night. After that, from the early morning to the morning of the 9th, some areas could see more than 50 mm per hour. In South Chungcheong, heavy rain could continue through the morning of the 9th.
In southern inland Gyeonggi and central and northern North Gyeongsang, heavy downpours of 30–50 mm per hour are expected from the early morning to the morning of the 9th, and in central and southern inland and mountainous Gangwon, from the morning to midday of the 9th.
As heavy rain is also forecast in North Korea, water levels could rise and flow speeds could increase in cross-border rivers such as the Imjin River, the Hantan River, and the Bukhan River. Extra caution is needed to prevent accidents in areas of northern Gyeonggi and northern Gangwon where these rivers flow.
Strong winds will accompany the rain. In the northern mountainous areas of Gangwon, gusts exceeding 90 kph and 25 m per second have been blowing since early this morning. In the rest of the central region; the coasts of North Jeolla and South Jeolla; and Jeju, winds with gusts around 55 kph will blow through the afternoon. In the mountains, gusts could strengthen to around 70 kph.
Even with the rain, the sweltering heat will not ease easily. This is because hot, humid air will continue to flow in along the edge of the North Pacific high-pressure system.
For the time being, high temperatures will exceed 30 C mainly inland, with apparent temperatures rising to around 31 C. In areas under heat advisories—including southeastern Gyeonggi, southern Gangwon, Sejong, central and southern North Chungcheong, northwestern North Jeolla, southeastern South Jeolla, Yeongnam, and Jeju—apparent temperatures could soar above 33 C.
As of 8 a.m., temperatures in major cities were 23.5 C in Seoul, 23.7 C in Incheon, 26.1 C in Daejeon, 27.2 C in Gwangju, 28.2 C in Daegu, 26.9 C in Ulsan, and 25.2 C in Busan. The day's highs are expected to range from 26 C to 33 C.
Seas will also be rough. In the far western sea under high seas advisories; the far southern waters off Jeju; the central western nearshore; and the North Jeolla nearshore, strong winds of 30–60 kph and 8–16 m per second will blow through the day, with waves rising 1.5–3.5 meters. However, the inner southeastern far waters off Jeju are excluded from the advisories.
Swells will reach Jeju's coast from the afternoon. Because high waves can wash over coastal rocks and breakwaters, it is best to avoid approaching the shore.