WTJP31 RJTD 142100 WARNING 142100. WARNING VALID 152100. STORM WARNING. SEVERE TROPICAL STORM 1607 CHANTHU (1607) 985 HPA AT 26.5N 145.1E OGASAWARA SHOTO MOVING NORTHNORTHEAST 11 KNOTS. POSITION FAIR. MAX WINDS 50 KNOTS NEAR CENTER. RADIUS OF OVER 30 KNOT WINDS 180 MILES EAST SEMICIRCLE AND 90 MILES ELSEWHERE. FORECAST POSITION FOR 150900UTC AT 28.2N 144.0E WITH 30 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 985 HPA, MAX WINDS 50 KNOTS NEAR CENTER. FORECAST POSITION FOR 152100UTC AT 30.2N 142.6E WITH 60 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 980 HPA, MAX WINDS 55 KNOTS NEAR CENTER. JAPAN METEOROLOGICAL AGENCY.=