WTJP32 RJTD 301500 WARNING 301500. WARNING VALID 011500. STORM WARNING. SEVERE TROPICAL STORM 1618 CHABA (1618) 985 HPA AT 15.1N 136.5E SEA EAST OF PHILIPPINES MOVING NORTHNORTHWEST 12 KNOTS. POSITION FAIR. MAX WINDS 55 KNOTS NEAR CENTER. RADIUS OF OVER 50 KNOT WINDS 30 MILES. RADIUS OF OVER 30 KNOT WINDS 150 MILES. FORECAST POSITION FOR 010300UTC AT 16.9N 134.9E WITH 40 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 985 HPA, MAX WINDS 55 KNOTS NEAR CENTER. FORECAST POSITION FOR 011500UTC AT 19.0N 132.7E WITH 60 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 980 HPA, MAX WINDS 60 KNOTS NEAR CENTER. JAPAN METEOROLOGICAL AGENCY.=