The Monsoon Is Not Over Yet... Rain Nationwide on the 20th-21st and 23rd-24th

Periodic Low Pressure Systems Bring Rain Through Weekend
80mm Rain on South Coast from Night of 20th to 21st
20~70mm Rain in Southern Chungcheong and Southern Regions
Rain in West and South Coast from Night of 23rd, Rain in Yeongdong Region on Afternoon of 24th

On the 13th, when the monsoon rain fell nationwide, commuters hurried their steps at Gwanghwamun Intersection in Seoul. / Photo by Mun Ho-nam munonam@

[Asia Economy Reporter Han Jinju] With two low-pressure systems passing through by the weekend, rain is expected nationwide from the night of the 20th until the morning of the 21st, and again from the 23rd to the 24th. Between the rain periods, a heatwave will occur.

The Korea Meteorological Administration (KMA) held an ad-hoc briefing on the 20th, stating that due to the influence of a low-pressure system accompanying a stationary front, the southern coast will receive heavy rainfall exceeding 80mm from tonight until the morning of the 21st, while the southern Chungcheong region, southern provinces, and Jeju Island will see about 20 to 70mm of rain. The northern Chungcheong and northern Gyeongbuk regions are expected to receive 5 to 30mm, and the Seoul metropolitan area and Gangwon Province around 5mm of rain.

Forecast analyst Woo Jin-gyu explained, "Cold and dry air is descending from the north, while warm air is flowing in from the southern flank of the North Pacific High, increasing the temperature gradient between north and south. This will cause the low-pressure system between the stationary fronts to affect our country. Strong rain clouds will form mainly over the southern provinces and southern Chungcheong region near the low-pressure system, and the southern coast will receive more rain due to topographical effects."

On the weekend, from the 23rd to the 24th, as the low-pressure system passes over the Korean Peninsula, rain will fall in various parts of the country. Compared to the rainfall on the 21st, the mixing of cold and warm air will be more widespread, intensifying the low-pressure system and resulting in heavier and more extensive rainfall. From the night of the 23rd, heavy rain is expected on the western and southern coasts, and from the afternoon of the 24th, concentrated heavy rain will occur in the Gangwon Yeongdong region. The areas of concentrated rainfall may change depending on the low-pressure system's path.

Analyst Woo said, "On the 23rd, the rain cloud area will develop more broadly north to south, and the rainfall intensity will be greater. The peak rainfall time will be on the night of the 23rd, with a long rain cloud band passing north to south centered on the western and southern coasts. In the Gangwon Yeongdong region, as the low-pressure system moves eastward, the rain cloud band will develop due to easterly winds."

Between now and the 26th, along with the two low-pressure systems passing through, localized showers and heatwaves will continue. Cold and dry air in the upper atmosphere combined with high pressure in the lower atmosphere will heat the surface, causing unstable convection and frequent showers.

Woo added, "Since this is a period with a high solar altitude and strong radiation heat, temperatures will rise, and the areas recording daytime highs above 30 degrees Celsius will expand on the 25th and 26th. Atmospheric instability will be greater on the 25th and 26th than on the 22nd, increasing the likelihood of frequent evening showers."

After the 27th, the North Pacific High is expected to expand toward Korea, the Tibetan High will move eastward, and tropical disturbances will move from the south, causing the stationary front to move northward. However, due to the high uncertainty in the occurrence and path of tropical disturbances (low-pressure systems originating in tropical regions), more time is needed to determine whether the North Pacific High will expand. In other words, it is still too early to declare the end of the monsoon season, according to the KMA.

Analyst Woo explained, "Tropical disturbances have not yet formed, and their uncertainty is much higher than other meteorological factors. We also need to consider the pressure pattern on the 25th and 26th, the tropical disturbances, and the timing of blocking pattern resolution. If tropical disturbances develop late or move southward, the North Pacific High may not advance northward, so it is premature to mention the end of the monsoon season."

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