WTJP31 RJTD 151500 WARNING 151500. WARNING VALID 161500. STORM WARNING. SEVERE TROPICAL STORM 1607 CHANTHU (1607) 985 HPA AT 29.9N 143.1E OGASAWARA SHOTO MOVING NORTHNORTHWEST 15 KNOTS. POSITION FAIR. MAX WINDS 50 KNOTS NEAR CENTER. RADIUS OF OVER 30 KNOT WINDS 210 MILES EAST SEMICIRCLE AND 120 MILES ELSEWHERE. FORECAST POSITION FOR 160300UTC AT 31.9N 141.8E WITH 40 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 985 HPA, MAX WINDS 50 KNOTS NEAR CENTER. FORECAST POSITION FOR 161500UTC AT 34.2N 141.1E WITH 60 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 985 HPA, MAX WINDS 50 KNOTS NEAR CENTER. JAPAN METEOROLOGICAL AGENCY.=