WTJP21 RJTD 310600 WARNING 310600. WARNING VALID 010600. WARNING IS UPDATED EVERY 6 HOURS. TYPHOON WARNING. SEVERE TROPICAL STORM 1604 NIDA (1604) 980 HPA AT 18.3N 122.3E SEA EAST OF PHILIPPINES MOVING NORTHWEST 11 KNOTS. POSITION GOOD. MAX WINDS 55 KNOTS NEAR CENTER. RADIUS OF OVER 50 KNOT WINDS 30 MILES. RADIUS OF OVER 30 KNOT WINDS 150 MILES EAST SEMICIRCLE AND 120 MILES ELSEWHERE. FORECAST POSITION FOR 311800UTC AT 19.1N 120.0E WITH 40 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 970 HPA, MAX WINDS 65 KNOTS NEAR CENTER. FORECAST POSITION FOR 010600UTC AT 20.5N 117.5E WITH 60 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 965 HPA, MAX WINDS 70 KNOTS NEAR CENTER. EXTENDED OUTLOOK. FORECAST POSITION FOR 020600UTC AT 22.5N 112.6E WITH 110 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 960 HPA, MAX WINDS 75 KNOTS NEAR CENTER. FORECAST POSITION FOR 030600UTC AT 24.0N 107.9E WITH 140 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 990 HPA. BECOMING TROPICAL DEPRESSION. JAPAN METEOROLOGICAL AGENCY.=