WTKO20 RKSL 120000 KMA TROPICAL CYCLONE ADVISORY NO. 4 NAME 1702 MERBOK ANALYSIS POSITION 120000UTC 20.2N 115.0E MOVEMENT NW 11KT PRES/VMAX 996HPA 39KT FORECAST 24HR POSITION 130000UTC 23.9N 114.6E WITHIN 0NM PRES 1002HPA KOREA METEOROLOGICAL ADMINISTRATION.