WTJP31 RJTD 012100 WARNING 012100. WARNING VALID 022100. STORM WARNING. SEVERE TROPICAL STORM 1604 NIDA (1604) DOWNGRADED FROM TYPHOON 975 HPA AT 22.7N 114.2E SOUTH CHINA MOVING WESTNORTHWEST 13 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 EAST SEMICIRCLE AND 150 MILES ELSEWHERE. FORECAST POSITION FOR 020900UTC AT 23.8N 111.6E WITH 40 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 985 HPA, MAX WINDS 45 KNOTS NEAR CENTER. FORECAST POSITION FOR 022100UTC AT 24.6N 109.5E WITH 60 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 992 HPA, MAX WINDS 35 KNOTS. JAPAN METEOROLOGICAL AGENCY.=