WTKO20 RKSL 011800 KMA TROPICAL CYCLONE ADVISORY NO. 20 NAME 1821 JEBI ANALYSIS POSITION 011800UTC 21.8N 136.6E MOVEMENT NW 10KT PRES/VMAX 930HPA 97KT FORECAST 24HR POSITION 021800UTC 25.2N 133.7E WITHIN 60NM PRES/VMAX 950HPA 84KT 48HR POSITION 031800UTC 30.1N 132.5E WITHIN 90NM PRES/VMAX 975HPA 62KT 72HR POSITION 041800UTC 40.7N 138.4E WITHIN 135NM PRES/VMAX 985HPA 52KT 96HR POSITION 051800UTC 51.3N 139.0E WITHIN 0NM PRES/VMAX 990HPA 47KT KOREA METEOROLOGICAL ADMINISTRATION.