WTJP31 RJTD 040900 WARNING 040900. WARNING VALID 050900. TYPHOON WARNING. TYPHOON 1821 JEBI (1821) 970 HPA AT 37.1N 136.5E SEA OF JAPAN MOVING NORTHNORTHEAST 36 KNOTS. POSITION GOOD. MAX WINDS 65 KNOTS NEAR CENTER. RADIUS OF OVER 50 KNOT WINDS 80 MILES SOUTHEAST SEMICIRCLE AND 30 MILES ELSEWHERE. RADIUS OF OVER 30 KNOT WINDS 300 MILES SOUTHEAST SEMICIRCLE AND 120 MILES ELSEWHERE. FORECAST POSITION FOR 042100UTC AT 45.0N 139.2E WITH 40 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 970 HPA, MAX WINDS 60 KNOTS NEAR CENTER. FORECAST POSITION FOR 050900UTC AT 50.5N 137.3E WITH 60 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 974 HPA, MAX WINDS 50 KNOTS. BECOMING EXTRATROPICAL LOW. JAPAN METEOROLOGICAL AGENCY.=