Typhoon 13, known as Dolphin, is moving toward eastern China while bypassing the Korean Peninsula. Meanwhile, Typhoon 15, Chan-hom, is expected to traverse the Japanese archipelago and potentially enter the East Sea. Although the likelihood of Chan-hom making landfall is low, its accompanying easterly winds and moisture could bring rain to the eastern coast of Korea, alleviating the ongoing heat wave.
According to the Korea Meteorological Administration on August 12, a weakened tropical depression from Typhoon Dolphin is located west of Shanghai, China, while Typhoon Chan-hom is positioned to the east. Dolphin has moved over the southern waters of the Korean Peninsula without directly impacting the country, but Chan-hom is anticipated to follow a path through northeastern Japan into the East Sea, likely affecting the eastern coast and southeastern regions of Korea.
Chan-hom is drawing attention due to its potential to bring easterly winds into Korea, depending on its position and rotation. In the Northern Hemisphere, typhoons and other low-pressure systems rotate counterclockwise. If Chan-hom settles east of the Korean Peninsula, it could create a structure that allows easterly winds to flow toward Korea.
These easterly winds will pick up moisture from the East Sea and, upon encountering the Taebaek Mountains, will rise and produce rain along the eastern coast. The air descending from the mountains will be relatively dry and warm, potentially leading to a Föhn effect. As a result, while the eastern coast may experience rain, the inland areas west of the Taebaek Mountains might not see significant temperature drops or could even warm up.
Current forecasts indicate that rain is expected primarily in the eastern coastal and mountainous regions of Gangwon and the northeastern areas of Gyeongbuk. By August 14, expected rainfall amounts are 30 to 80 mm for Ulleungdo and Dokdo, 20 to 60 mm for the eastern coast and mountainous areas of Gangwon and Gyeongbuk, 10 to 40 mm for the southern coast of Busan, Ulsan, and Gyeongnam, and around 5 mm for the mountainous regions of Jeju.
Notably, rain is expected along the Gyeongnam coast and eastern inland areas from the afternoon to night of August 13, with additional rain anticipated in the mountainous regions of Jeju starting the night of August 14.
Another reason for the interest in Chan-hom is its potential to alter the pressure systems that have contributed to the recent heat dome over the Korean Peninsula. A strong high-pressure system that had been dominating the area has weakened, leading to a temporary reduction in the heat wave. On August 10, Seoul recorded a low of 24.8 degrees Celsius, breaking a two-day tropical night streak, while Daecheong in Gangwon dropped to 17.6 degrees Celsius.
Chan-hom's approach could complicate these pressure changes further. As the typhoon moves east of the Korean Peninsula, it may disturb the edges of the high-pressure system and strengthen the easterly winds, potentially pushing some of the hot air aloft out of the region and temporarily alleviating the heat wave.
However, it is difficult to assert that Chan-hom will completely break the heat dome. The typhoon's center is expected to remain far from the Korean Peninsula, and its impacts are likely to be concentrated on the eastern coast and surrounding seas.
In drought-affected areas, the rain brought by Chan-hom could be welcome news. However, as the easterly winds meet the Taebaek Mountains, there is a possibility of concentrated rainfall in specific regions. Therefore, Chan-hom should not be viewed solely as a 'savior typhoon' for drought relief. The amount of rainfall and areas of heavy downpours will depend on the typhoon's position, speed, and moisture influx, necessitating close monitoring of the latest forecasts.
At sea, Chan-hom's effects are expected to be more direct. Strong winds and high waves are anticipated in the East Sea, particularly in the central and southern regions, where rough seas may develop. The southern seas of the West Sea may also experience increased winds due to the weakened tropical depression from Dolphin.
Currently, the timing coincides with a spring tide, which could lead to flooding along the coast due to rising sea levels during high tide. There is a risk of strong swells along the southern coasts of Jeonnam, Gyeongnam, and Jeju, so it is advisable to avoid activities such as watching waves from breakwaters or rocky shores.
Even if the typhoon does not make landfall, the winds, moisture, and high waves surrounding it can create dangerous conditions. Additionally, it remains to be seen whether the heat wave will completely dissipate after Chan-hom's influence. Although the high-pressure system may weaken temporarily due to the typhoon, if a high-pressure system reestablishes itself around the Korean Peninsula after the typhoon passes, temperatures could rise quickly again.
Historically, there have been instances where typhoons have temporarily alleviated heat waves, only for high pressure to expand again, leading to a resurgence of heat. Therefore, it is more appropriate to view Chan-hom as a short-term variable that disrupts the pressure system over the Korean Peninsula rather than a definitive end to the heat wave.
The Korea Meteorological Administration urges the public to stay updated on the latest typhoon information and weather advisories, as the path and intensity of the typhoon may continue to change.
* This article has been translated by AI.
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