WTJP23 RJTD 161800 WARNING 161800. WARNING VALID 171800. WARNING IS UPDATED EVERY 6 HOURS. TYPHOON WARNING. TYPHOON 1511 NANGKA (1511) 975 HPA AT 34.1N 133.7E SHIKOKU MOVING NORTHNORTHWEST 12 KNOTS. POSITION GOOD. MAX WINDS 65 KNOTS NEAR CENTER. RADIUS OF OVER 50 KNOT WINDS 70 MILES SOUTHEAST SEMICIRCLE AND 50 MILES ELSEWHERE. RADIUS OF OVER 30 KNOT WINDS 325 MILES SOUTHEAST SEMICIRCLE AND 270 MILES ELSEWHERE. FORECAST POSITION FOR 170600UTC AT 35.9N 133.5E WITH 50 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 985 HPA, MAX WINDS 50 KNOTS NEAR CENTER. FORECAST POSITION FOR 171800UTC AT 37.6N 134.2E WITH 85 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 994 HPA, MAX WINDS 45 KNOTS NEAR CENTER. EXTENDED OUTLOOK. FORECAST POSITION FOR 181800UTC AT 40.2N 137.5E WITH 160 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 1006 HPA. BECOMING TROPICAL DEPRESSION. JAPAN METEOROLOGICAL AGENCY.=