WTJP31 RJTD 152100 WARNING 152100. WARNING VALID 162100. STORM WARNING. TROPICAL STORM 1607 CHANTHU (1607) 985 HPA AT 30.8N 142.6E SEA EAST OF JAPAN MOVING NORTHWEST 13 KNOTS. POSITION FAIR. MAX WINDS 45 KNOTS NEAR CENTER. RADIUS OF OVER 30 KNOT WINDS 210 MILES EAST SEMICIRCLE AND 120 MILES ELSEWHERE. FORECAST POSITION FOR 160900UTC AT 33.2N 140.9E WITH 40 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 985 HPA, MAX WINDS 45 KNOTS NEAR CENTER. FORECAST POSITION FOR 162100UTC AT 35.8N 141.1E WITH 60 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 985 HPA, MAX WINDS 50 KNOTS NEAR CENTER. JAPAN METEOROLOGICAL AGENCY.=