WTJP33 RJTD 162100 WARNING 162100. WARNING VALID 172100. STORM WARNING. SEVERE TROPICAL STORM 1511 NANGKA (1511) DOWNGRADED FROM TYPHOON 985 HPA AT 34.5N 133.7E WESTERN JAPAN MOVING NORTHNORTHWEST 11 KNOTS. POSITION GOOD. MAX WINDS 50 KNOTS. RADIUS OF OVER 30 KNOT WINDS 210 MILES. FORECAST POSITION FOR 170900UTC AT 36.1N 133.6E WITH 50 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 992 HPA, MAX WINDS 45 KNOTS. FORECAST POSITION FOR 172100UTC AT 37.9N 134.6E WITH 85 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 998 HPA, MAX WINDS 35 KNOTS. JAPAN METEOROLOGICAL AGENCY.=