WTJP21 RJTD 010600 WARNING 010600. WARNING VALID 020600. WARNING IS UPDATED EVERY 6 HOURS. TYPHOON WARNING. SEVERE TROPICAL STORM 1604 NIDA (1604) 975 HPA AT 21.3N 117.4E SOUTH CHINA SEA MOVING WESTNORTHWEST 16 KNOTS. POSITION GOOD. MAX WINDS 60 KNOTS NEAR CENTER. RADIUS OF OVER 50 KNOT WINDS 60 MILES. RADIUS OF OVER 30 KNOT WINDS 180 MILES. FORECAST POSITION FOR 011800UTC AT 22.2N 114.9E WITH 40 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 965 HPA, MAX WINDS 70 KNOTS NEAR CENTER. FORECAST POSITION FOR 020600UTC AT 23.0N 112.4E WITH 60 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 975 HPA, MAX WINDS 60 KNOTS NEAR CENTER. EXTENDED OUTLOOK. FORECAST POSITION FOR 030600UTC AT 24.7N 107.7E WITH 110 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 996 HPA. BECOMING TROPICAL DEPRESSION. JAPAN METEOROLOGICAL AGENCY.=