WTJP21 RJTD 031200 WARNING 031200. WARNING VALID 041200. WARNING IS UPDATED EVERY 6 HOURS. STORM WARNING. SEVERE TROPICAL STORM 1703 NANMADOL (1703) 985 HPA AT 29.4N 126.2E EAST CHINA SEA MOVING NORTHNORTHEAST 20 KNOTS. POSITION GOOD. MAX WINDS 55 KNOTS NEAR CENTER. RADIUS OF OVER 50 KNOT WINDS 20 MILES. RADIUS OF OVER 30 KNOT WINDS 100 MILES EAST SEMICIRCLE AND 80 MILES ELSEWHERE. FORECAST POSITION FOR 040000UTC AT 32.8N 130.0E WITH 40 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 990 HPA, MAX WINDS 50 KNOTS NEAR CENTER. FORECAST POSITION FOR 041200UTC AT 34.2N 137.4E WITH 80 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 996 HPA, MAX WINDS 40 KNOTS NEAR CENTER. EXTENDED OUTLOOK. FORECAST POSITION FOR 051200UTC AT 37.4N 151.6E WITH 150 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 1000 HPA. BECOMING TROPICAL DEPRESSION. JAPAN METEOROLOGICAL AGENCY.=