WTJP22 RJTD 031800 WARNING 031800. WARNING VALID 041800. WARNING IS UPDATED EVERY 6 HOURS. STORM WARNING. SEVERE TROPICAL STORM 1510 LINFA (1510) 985 HPA AT 15.2N 124.3E SEA EAST OF PHILIPPINES MOVING WEST 08 KNOTS. POSITION FAIR. MAX WINDS 50 KNOTS NEAR CENTER. RADIUS OF OVER 30 KNOT WINDS 120 MILES SOUTH SEMICIRCLE AND 60 MILES ELSEWHERE. FORECAST POSITION FOR 041800UTC AT 17.1N 123.1E WITH 70 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 980 HPA, MAX WINDS 55 KNOTS NEAR CENTER. EXTENDED OUTLOOK. FORECAST POSITION FOR 051800UTC AT 18.4N 121.6E WITH 110 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 975 HPA, MAX WINDS 60 KNOTS NEAR CENTER. FORECAST POSITION FOR 061800UTC AT 19.5N 121.1E WITH 160 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 970 HPA, MAX WINDS 65 KNOTS NEAR CENTER. JAPAN METEOROLOGICAL AGENCY.=