WTJP32 RJTD 090900 WARNING 090900. WARNING VALID 100900. STORM WARNING. SEVERE TROPICAL STORM 1813 SHANSHAN (1813) 980 HPA AT 37.6N 141.9E SEA EAST OF JAPAN MOVING NORTHNORTHEAST 11 KNOTS. POSITION GOOD. MAX WINDS 55 KNOTS NEAR CENTER. RADIUS OF OVER 50 KNOT WINDS 40 MILES SOUTHEAST SEMICIRCLE AND 10 MILES ELSEWHERE. RADIUS OF OVER 30 KNOT WINDS 240 MILES SOUTHEAST SEMICIRCLE AND 150 MILES ELSEWHERE. FORECAST POSITION FOR 092100UTC AT 39.3N 145.0E WITH 40 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 980 HPA, MAX WINDS 55 KNOTS NEAR CENTER. FORECAST POSITION FOR 100900UTC AT 40.9N 151.1E WITH 80 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 980 HPA, MAX WINDS 55 KNOTS NEAR CENTER. JAPAN METEOROLOGICAL AGENCY.=