Jeju and South Coast Monsoon Starts on 20-21... Heatwave in Inland Areas from 18 to 20

Influence of stationary front and low pressure brings heavy rain to Jeju and southern coast from 21 to 23
Too early to determine start of monsoon in southern regions
Inland areas hot and humid from 18 to 20
5-30mm rain expected in eastern Gyeonggi and inland/mountain areas of Gangwon from afternoon to evening on 18th

[Asia Economy Reporter Han Jinju] The monsoon season is expected to begin between the 20th and 21st in Jeju Island and the southern coastal areas. Heatwaves will continue mainly in inland regions from the 18th to the 20th.

The Korea Meteorological Administration (KMA) held an unscheduled briefing on the 17th, announcing that the monsoon will start in Jeju Island and the southern coastal areas from the afternoon of the 20th. As the stationary front moves northward accompanied by a low-pressure system, heavy rain is expected mainly in Jeju and the southern coast from the 21st to the 23rd, so preparations for monsoon damage are necessary.

Forecast analyst Woo Jin-gyu explained, "As the stationary front moves northward, rain will fall mainly in Jeju Island, marking the start of the monsoon from the Jeju area. Although rain clouds will expand to the southern regions on the 21st and 22nd, it is currently difficult to determine the exact timing of the monsoon onset in the southern regions. If the low-pressure system does not move northward, areas north of the southern coast, such as northern Jeollanam-do or northern Gyeongsangnam-do, may not be affected by the rain cloud band."

From the 21st to the 23rd, the Tibetan high pressure and the North Pacific high pressure will collide, causing atmospheric instability and moisture inflow, resulting in heavy rainfall. As the North Pacific high moves northward, it will draw humid air from the south, leading to localized heavy rain in Jeju and some parts of the southern coast. With a large amount of moisture inflow, the volume of rain is expected to increase significantly.

The KMA's medium-term forecast predicts rain from the 21st to the 22nd in Jeonbuk, Jeonnam, Gwangju, Daegu, Gyeongbuk, Busan, and Gyeongnam, with rain in Jeju from the 20th to the 23rd. Forecast analyst Woo urged, "Heavy rain is expected in Jeju and some southern regions. Since damage such as farmland destruction and landslides can be severe when rain falls after a prolonged drought, thorough preparation in advance is necessary."

On the 17th and 18th, due to atmospheric instability, showers will occur in central regions. Until the night of the 17th, scattered showers of about 5 to 40mm will fall across inland areas nationwide. From early morning to morning on Saturday the 18th, influenced by a trough, about 5mm of rain will fall mainly in the Seoul metropolitan area. From daytime to evening on the 18th, 5 to 30mm of rain will fall in eastern Gyeonggi and inland/mountainous areas of Gangwon. Thunder, lightning, gusts, and hail are expected in some areas.

Before the monsoon starts in Jeju, from Saturday the 18th to the 20th, heatwave-level heat will continue mainly in inland areas. Based on Daegu, the highest daytime temperature on the 18th will be above 32 degrees Celsius, rising to 34 degrees on the 19th. Many inland areas are expected to experience a maximum perceived temperature above 33 degrees Celsius.

Forecast analyst Woo explained, "Hot heat will accumulate in the inland areas of Gyeongsang Province, and with moisture inflow from the south, hot and humid weather is expected, with the possibility of heatwave warnings being issued."

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