Heavy Precipitation Expected over the Korean Peninsula and Japan

Affected by the eastward movement of a low vortex and the Mei-yu Front (Fig. 1), moderate to heavy rainfall is forecast across the Korean Peninsula？ and central to southern Japan？ from June 19 to 21. Localized heavy downpours are expected, accompanied by short-term intense precipitation？ and thunderstorm gales. Additionally, coastal gusts may reach force 7 to 9 on the Beaufort scale. The estimated cumulative precipitation in these regions will range between 50 to 90 mm, with localized amounts exceeding 150 mm？ (Fig. 2). There is a significant risk of secondary disasters induced by the heavy rainfall, including flash floods, landslides, debris flows, and urban inundation. Residents are advised to avoid traveling to low-lying areas and mountainous regions.

Figure 1: Forecast of 500 hPa Geopotential Height (contours, unit: dagpm) and 850 hPa Wind Field (barbs, unit: m/s) at 20:00 BJT on June 20, 2026

Figure 2: Forecast of Accumulated Precipitation (shaded, unit: mm) from 20:00 BJT on June 19 to 08:00 BJT on June 22, 2026

https://www.wmc-bj.net

Author: Xiong Minquan                                          Reviewer: Cai Xiangning 

English reviewer:Wang Yi                                        Issue approver:Dai Kan