(LEAD) Autumn heat wave to end after heavy rain this weekend

South Korea is forecast to be soaked by heavy rain later this week after an unprecedented autumn heat wave, the state weather agency said Thursday, with the government scurrying to devise measures to prevent possible damage.Monsoon-like downpours will sporadically drench the nation between Friday afternoon and Saturday, lowering daytime highs nationwide to between 19 C and 30 C beginning this weekend, according to the Korea Meteorological Administration (KMA).Amid the weakening of the Tibetan high that has caused the unseasonal heat wave over the Korean Peninsula, cold air from the north will collide with hot and humid air rising from the south, resulting in heavy rain across the country, the KMA explained.Source: Yonhap News Agency