WTJP22 RJTD 300600 WARNING 300600. WARNING VALID 010600. WARNING IS UPDATED EVERY 6 HOURS. TYPHOON WARNING. SEVERE TROPICAL STORM 1618 CHABA (1618) 985 HPA AT 13.6N 137.0E SEA EAST OF PHILIPPINES MOVING WEST 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 301800UTC AT 15.3N 135.6E WITH 40 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 985 HPA, MAX WINDS 55 KNOTS NEAR CENTER. FORECAST POSITION FOR 010600UTC AT 17.1N 134.1E WITH 60 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 970 HPA, MAX WINDS 70 KNOTS NEAR CENTER. EXTENDED OUTLOOK. FORECAST POSITION FOR 020600UTC AT 21.2N 130.4E WITH 110 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 950 HPA, MAX WINDS 85 KNOTS NEAR CENTER. FORECAST POSITION FOR 030600UTC AT 25.8N 128.1E WITH 140 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 950 HPA, MAX WINDS 85 KNOTS NEAR CENTER. JAPAN METEOROLOGICAL AGENCY.=