WTJP32 RJTD 232100 WARNING 232100. WARNING VALID 242100. STORM WARNING. SEVERE TROPICAL STORM 1820 CIMARON (1820) 990 HPA AT 37.8N 135.5E SEA OF JAPAN MOVING NORTH 26 KNOTS. POSITION FAIR. MAX WINDS 55 KNOTS. RADIUS OF OVER 50 KNOT WINDS 30 MILES. RADIUS OF OVER 30 KNOT WINDS 300 MILES SOUTHEAST SEMICIRCLE AND 150 MILES ELSEWHERE. FORECAST POSITION FOR 240900UTC AT 41.4N 138.7E WITH 40 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 996 HPA, MAX WINDS 40 KNOTS. FORECAST POSITION FOR 242100UTC AT 42.3N 145.1E WITH 80 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 998 HPA. BECOMING EXTRATROPICAL LOW. JAPAN METEOROLOGICAL AGENCY.=