Heavy Monsoon Rain Nationwide Until Wednesday Night...Pours During Nighttime Vulnerable Hours Regardless of Region

Landslide Warning... Jeju Heatwave Advisory

On the 8th, when heavy rain fell in Seoul and the central region, vehicles near Suwon, Gyeonggi Province, were driving through splashing water. Photo by Jo Yongjun jun21@

Until the night of the 10th, due to the influence of the stationary front and a low-pressure system developed along the front, the nationwide monsoon rain is expected to continue.

According to the Korea Meteorological Administration on the 8th, from the 9th to the 10th, rainfall of 20 to 60 mm is expected on the east coast of Gangwon and Jeju, and 10 to 40 mm on the five western islands, Ulleungdo, and Dokdo. Except for these areas, 30 to 80 mm of rain is forecast nationwide. In the southern Gyeonggi region, inland southern Gangwon, central and southern Gangwon mountainous areas, Chungcheong, Honam, northern Gyeongbuk, and western Gyeongnam, more than 120 mm of rain may pour.

The area, timing, and amount of rainfall can vary significantly depending on the position of the stationary front and the intensity of the low-pressure system developed along the front. There is also a relatively large difference between the numerical forecast models, resulting in a wide range of expected rainfall amounts presented by the Korea Meteorological Administration.

Since heavy rain has fallen since the start of the monsoon and its effects have accumulated, it is necessary to prepare based on the 'maximum expected rainfall.' Especially, most regions nationwide are under a 'caution' level landslide warning, so landslides should be carefully monitored.

By region, the expected time periods of heavy rain and hourly rainfall amounts are as follows: Seoul metropolitan area 'from the night of the 9th to the morning of the 10th, 30 to 50 mm,' inland and mountainous areas of Gangwon 'from dawn to morning on the 10th, 30 to 50 mm,' east coast of Gangwon 'from dawn to morning on the 10th, 20 to 30 mm,' Chungcheong 'from dawn to morning on the 9th, 20 to 30 mm' and 'from dawn to morning on the 10th, 30 to 50 mm,' etc.

On the 8th, when heavy monsoon rain was forecasted, flood prevention water barriers were prepared at a building in Namseong Sagye Market, Dongjak-gu, Seoul. This place suffered significant damage due to flooding caused by heavy rain two years ago. Photo by Jin-Hyung Kang aymsdream@

In Honam, hourly rainfall of 20 to 30 mm is expected 'from dawn to morning on the 9th' and 30 to 50 mm 'from late night on the 9th to morning on the 10th.' In Yeongnam, 20 to 30 mm per hour is expected 'from night on the 8th to morning on the 9th' and 'from dawn to morning on the 10th.'

Regardless of the region, heavy rain is forecast during the vulnerable nighttime hours. This is because the lower-level jet supplying hot and humid air strengthens during this time. The lower-level jet is a fast wind blowing at speeds of 10 to 12.5 m/s at altitudes of 750 to 1500 meters.

Until the 10th, most areas will be affected by the stationary front, but Jeju will be located at the edge of the North Pacific High. Jeju will be hotter than other regions, with a perceived temperature rising to around 33 degrees Celsius. Tropical nights will also appear in Jeju until the 9th. Currently, a heatwave warning is in effect for northern and eastern Jeju, and a heatwave advisory is in place for the mid-mountainous northern Jeju.

The southern regions will also see the highest perceived temperature rise to around 31 degrees Celsius on the 9th, and on the 10th, most areas will have perceived temperatures around 31 degrees. The lowest morning temperatures on the 9th are expected to be 22 to 26 degrees, and the highest daytime temperatures 25 to 30 degrees. The expected minimum and maximum temperatures for major cities are: △ Seoul 23°C and 27°C △ Incheon 22°C and 26°C △ Daejeon 23°C and 27°C △ Gwangju 24°C and 29°C △ Daegu 25°C and 29°C △ Ulsan 25°C and 29°C △ Busan 24°C and 27°C.

Sea fog will persist over most seas for the time being. Sea fog will be denser over the West Sea, South Sea, and Jeju waters, and as this fog moves toward the coast, the central west coast, southern Jeolla coast, and southern Gyeongsang coast will also be covered in fog until the morning of the 9th.

Gusty winds, thunder, and lightning will continue over the West Sea and East Sea for the time being. Rough seas will intensify from the night of the 8th to the 9th in the distant East Sea, and from the night of the 9th in the distant West Sea and south of Jeju. On the 10th, severe weather is expected over most seas.