Tomorrow Marks the Start of the 'Full-Scale Jangma'... Seoul Metropolitan Area May Face 250mm Water Bombardment

Formation of a 'Narrow Rain Cloud Band'... Typical Monsoon
Rainfall May Vary Depending on Atmospheric Conditions

Over the past few days, unstable atmospheric conditions have caused intermittent rain, but on the 13th, a more 'typical monsoon rain' is expected.

According to the Korea Meteorological Administration, as of 11 a.m. on the 12th, rain has mostly stopped in most areas, with only around 5mm per hour falling along the southern coast of Gyeongnam. However, the atmosphere remains unstable, and scattered showers may occur in the afternoon.

However, this lull is not expected to last long. A stationary front formed over inland China is developing a low-pressure system, which is pulling the front toward northern North Korea, allowing a large influx of warm and humid monsoon air into the country.

Citizens are walking with umbrellas in the sudden heavy rain that fell in Seoul.
[Photo by Yonhap News]

Accordingly, rain will begin in the west, including Chungnam and Honam, from early morning on the 13th and will spread nationwide by the morning.

Afterward, as the low-pressure system and stationary front separate, cold and dry air will collide with the warm and humid air flowing in from the southwest, forming a 'narrow band of rain clouds' on the 14th. From that day, it is expected to be a 'typical monsoon' with heavy rain pouring in areas where the rain cloud band forms.

From the 13th to the 14th, 50 to 150mm of rain is expected nationwide except for Jeju, where 5 to 40mm is forecast. However, some areas in the Seoul metropolitan area may receive over 250mm of rainfall over the two days, and inland and mountainous areas of Gangwon and northern Chungcheong may see up to 200mm or more.

Additionally, from the afternoon of the 13th, parts of the Seoul metropolitan area, inland and mountainous Gangwon, and northern Chungcheong may experience 30 to 80mm of rain per hour accompanied by gusts, lightning, and thunder.

However, there are factors that could cause precipitation to deviate from forecasts. If the low-pressure system near the Bohai Sea intensifies strongly on the 13th, heavy rain areas may shift toward North Korea, and depending on how much cold and dry air from the northwest flows in on the 14th, the areas receiving rain could change.

Meanwhile, the stationary front is expected to fluctuate north and south near Korea until the 18th. Rain is forecast nationwide until the 17th, in the central region on the 18th, and mainly in the southern region and Jeju on the 19th and 20th, respectively.

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