WTJP22 RJTD 030600 WARNING 030600. WARNING VALID 040600. WARNING IS UPDATED EVERY 6 HOURS. STORM WARNING. SEVERE TROPICAL STORM 1510 LINFA (1510) UPGRADED FROM TROPICAL STORM 990 HPA AT 15.3N 126.0E SEA EAST OF PHILIPPINES MOVING WEST SLOWLY. POSITION FAIR. MAX WINDS 50 KNOTS NEAR CENTER. RADIUS OF OVER 30 KNOT WINDS 180 MILES SOUTH SEMICIRCLE AND 120 MILES ELSEWHERE. FORECAST POSITION FOR 040600UTC AT 16.9N 123.9E WITH 70 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 980 HPA, MAX WINDS 55 KNOTS NEAR CENTER. EXTENDED OUTLOOK. FORECAST POSITION FOR 050600UTC AT 18.4N 121.7E WITH 110 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 970 HPA, MAX WINDS 65 KNOTS NEAR CENTER. FORECAST POSITION FOR 060600UTC AT 18.8N 120.8E WITH 160 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 965 HPA, MAX WINDS 70 KNOTS NEAR CENTER. JAPAN METEOROLOGICAL AGENCY.=