While South Korea’s southern regions were hit with heat wave warnings, the Korea Meteorological Administration reported on Monday that the Greater Seoul region and Gangwon Province will see heavy rain showers on an occasional basis until Wednesday.
On Monday, the Greater Seoul area, which consists of Seoul, Incheon and Gyeonggi Province, expected to see 20 to 60 millimeters of rain, with heavily hit regions seeing up to 80 mm.
Specifically, the KMA added that the Greater Seoul area will also see 30 mm of rain per hour from Monday night to Tuesday afternoon.
The KMA additionally predicted that the central region -- which consists of Greater Seoul and Gangwon Province -- will see rain throughout the entire day on Tuesday while the central region can expect intermittent showers on Wednesday. Over the next two days, Greater Seoul can anticipate up to 80 mm of rain, while Gangwon Province can expect to see 10 to 60 mm of rain.
In contrast, heat wave warnings were issued in the southern region, which consists of North and South Jeolla Provinces, North and South Gyeongsang Provinces and Jeju Island, as temperatures were expected to feel as hot as high as 35 degrees Celsius. In Korea, heat wave advisories are issued when the highest apparent temperature is expected to reach 33 C or higher for two or more consecutive days.
According to weather experts, precipitation patterns during the monsoon season have been changing in Korea over the last few years.
In the past, monsoon seasons tended to last for a long period of time covering relatively large areas at once. However, it has recently changed to heavy rainfall concentrating in smaller areas for a shorter period of time, while other regions see little to no rain.
Back in the 1970s when weather records were first recorded, the number of days with more than 50 mm of rain per hour was only 7.1 days per year. On July 10, the North and South Chungcheong Provinces, North Jeolla Province and North Gyeongsang Province together saw more than 100 mm of rain per hour, which the KMA cited as a weather event that could occur “once every 200 years.”
Atmospheric science professor Son Seok-woo from Seoul National University told The Korea Herald that the recent changes in precipitation patterns could be due to the development of “narrow and long precipitation zones.”
“The recent development of narrow precipitation zones over South Korea can be said to be due to the clash between warm southwesterly winds and dry air from the north as the North Pacific anticyclone expands toward the south,” mentioned Son. “These are two extremely different air masses that can compress rain clouds, leading to heavy rainfall in smaller regions.”
Son added that narrower precipitation zones can bring heavy rainfall, but they also “create polarization in weather conditions,” as areas impacted by the precipitation zone will experience heavy rainfall, while those outside of it can experience heat waves.
