'Once-in-200-Years' Downpour Hits Geoje and Tongyeong... After Heavy Rain, Intense Heat Returns [Weather]

Although the heavy rain that continued throughout the southern regions during the holiday is expected to subside, on Tuesday, August 18, some areas of the Chungcheong region and the southern parts of the country may still experience scattered showers. In areas where the rain has stopped, humid air will contribute to hot and muggy conditions.

On the afternoon of the 17th, a road in Okpo-dong, Geoje City, Gyeongnam Province, is flooded. Photo by Yonhap News.

According to detailed regional observation data (AWS), cumulative precipitation from the 15th to the 17th reached 972 mm in Geoje and 751 mm in Tongyeong. The usual summer (June to August) rainfall in the Geoje area is 935 mm, meaning that more rain fell in just three days than typically falls over the entire three-month summer period. The Korea Meteorological Administration analyzed this as an extreme rainfall event that statistically occurs once every 200 years.

The primary cause of this record-breaking rainfall is attributed to a strong southern wind known as a 'low-level jet.' As a strong low-pressure system to the west and a high-pressure system to the east set up, a powerful low-level jet stream formed, bringing large amounts of moisture from the south to the Korean Peninsula. In addition, moisture left by Typhoon Dolphin and warm, humid sea air contributed to the downpours. Much of the water vapor from the south collided with the coastal topography of the southern coast, including Geoje and Tongyeong, forming thick rain clouds, and was trapped in place by the eastern high-pressure system. This caused heavy rainfall to be concentrated over specific areas.

Until the morning of this day, some rain is expected in Gyeongnam, as well as in the southern coast of Jeonnam and the southern part of Gyeongbuk from early morning into midday, and in Jeju Island into the afternoon. Expected precipitation is as follows: ● Jeonnam southern coast: 5–20 mm ● Busan, Ulsan, southern coast of Gyeongnam: 20–60 mm ● Inland Gyeongnam, Daegu and southern Gyeongbuk: 5–30 mm ● Ulleungdo and Dokdo: 5–20 mm ● Jeju Island: 10–60 mm. As heavy rain mainly affects the southern coast of Gyeongnam, weakened ground conditions may increase the risk of landslides and related dangers.

From the afternoon to evening, scattered showers are expected in southern Chungcheong and the southern regions. Forecast rainfall from showers is as follows: ● Southeastern inland of Chungnam and southern Chungbuk: 5–30 mm ● Southeastern Jeonbuk, Gwangju, and Jeonnam: 5–30 mm ● Busan, Ulsan, Gyeongnam, Daegu, and southern Gyeongbuk: 5–30 mm. In areas where showers occur, localized strong gusts may also be experienced.

In regions where rain or showers fall, temperatures may temporarily decrease; however, after the rain or showers stop, temperatures are expected to rise again amid continued high humidity, leading to sultry weather. The forecasted daytime highs for major cities are as follows: Seoul 32°C, Incheon 31°C, Chuncheon 31°C, Gangneung 32°C, Daejeon 32°C, Daegu 32°C, Gwangju 32°C, Busan 31°C, Jeju 32°C.

With heat advisories in effect on parts of the Jeolla West Coast, the highest perceived temperatures are expected to approach 33°C across the capital region, the Chungcheong region, and the southern parts of the country, resulting in very hot conditions. In some urban and coastal areas, overnight temperatures may not sufficiently decrease, with some minimum nighttime temperatures remaining at or above 25°C, creating conditions for tropical nights.

Fine dust (particulate matter) levels are expected to be 'good' nationwide.

This content was produced with the assistance of AI translation services.