WTJP31 RJTD 310900 WARNING 310900. WARNING VALID 010900. TYPHOON WARNING. TYPHOON 1821 JEBI (1821) 915 HPA AT 18.3N 142.2E MARIANAS MOVING WEST 13 KNOTS. POSITION GOOD. MAX WINDS 105 KNOTS NEAR CENTER. RADIUS OF OVER 50 KNOT WINDS 60 MILES. RADIUS OF OVER 30 KNOT WINDS 180 MILES NORTH SEMICIRCLE AND 150 MILES ELSEWHERE. FORECAST POSITION FOR 312100UTC AT 19.2N 140.0E WITH 40 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 905 HPA, MAX WINDS 110 KNOTS NEAR CENTER. FORECAST POSITION FOR 010900UTC AT 20.5N 138.2E WITH 60 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 915 HPA, MAX WINDS 105 KNOTS NEAR CENTER. JAPAN METEOROLOGICAL AGENCY.=