South Korea's monsoon rains are set to dampen the long weekend beginning with the Constitution Day holiday on Friday. Weather forecasters warn that central regions face the greatest risk of torrential downpours as the country comes under unstable atmospheric conditions. Pedestrians cross a street near Gwanghwamun Station in central Seoul on July 14 as heavy rain falls. (Yonhap) According to the Korea Meteorological Administration, rain will begin falling in the Chungcheong, Jeolla and Gyeongsang provinces from Friday afternoon before spreading to other areas.From early Saturday into Saturday morning, hourly rainfall of 20 to 50 millimeters is forecast in many regions, and heavy rain advisories are likely to be issued. In some areas of southern Gyeonggi Province, Gangwon Province and the Chungcheong provinces, rainfall could reach around 80 millimeters per hour, potentially triggering emergency alerts.Forecasters warned that rainfall will intensify over the weekend as the monsoon front moves northward after drawing moisture from warm seas. The KMA expects central regions, including the Seoul metropolitan area, Gangwon Province, the Chungcheong provinces and parts of North Gyeongsang Province, to face the greatest risk of torrential downpours.According to the KMA, the monsoon front is expected to remain active into next week, moving back and forth across the Korean Peninsula and bringing repeated rounds of rain to different regions through the latter part of the week.