WTJP31 RJTD 121500 WARNING 121500. WARNING VALID 131500. STORM WARNING. SEVERE TROPICAL STORM 1702 MERBOK (1702) 990 HPA AT 22.4N 114.5E SOUTH CHINA SEA MOVING NORTH 10 KNOTS. POSITION FAIR. MAX WINDS 50 KNOTS NEAR CENTER. RADIUS OF OVER 30 KNOT WINDS 90 MILES. FORECAST POSITION FOR 130300UTC AT 24.5N 114.3E WITH 30 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 1004 HPA. BECOMING TROPICAL DEPRESSION. FORECAST POSITION FOR 131500UTC AT 25.9N 116.0E WITH 60 MILES RADIUS OF 70 PERCENT PROBABILITY CIRCLE. 1004 HPA. BECOMING TROPICAL DEPRESSION. JAPAN METEOROLOGICAL AGENCY.=