SUBJ: TROPICAL CYCLONE WARNING WTPN32 PGTW 291500 1. TROPICAL STORM 30W (XANGSANE) WARNING NR 017 01 ACTIVE TROPICAL CYCLONE IN NORTHWESTPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 291200Z4 --- NEAR 16.0N7 117.9E8 MOVEMENT PAST SIX HOURS - 300 DEGREES AT 02 KTS POSITION ACCURATE TO WITHIN 025 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT RADIUS OF 050 KT WINDS - 030 NM RADIUS OF 035 KT WINDS - 130 NM NORTH SEMICIRCLE OVER WATER 115 NM ELSEWHERE OVER WATER REPEAT POSIT: 16.0N7 117.9E8 --- FORECASTS: 12 HRS, VALID AT: 300000Z3 --- 16.4N1 117.2E1 MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT RADIUS OF 050 KT WINDS - 035 NM RADIUS OF 035 KT WINDS - 140 NM NORTH SEMICIRCLE 120 NM ELSEWHERE VECTOR TO 24 HR POSIT: 340 DEG/ 05 KTS --- 24 HRS, VALID AT: 301200Z6 --- 17.4N2 116.8E6 MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT RADIUS OF 050 KT WINDS - 055 NM NORTH SEMICIRCLE 035 NM ELSEWHERE RADIUS OF 035 KT WINDS - 150 NM NORTH SEMICIRCLE 125 NM ELSEWHERE VECTOR TO 36 HR POSIT: 010 DEG/ 06 KTS --- 36 HRS, VALID AT: 310000Z4 --- 18.5N4 117.0E9 MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT RADIUS OF 050 KT WINDS - 050 NM NORTH SEMICIRCLE 030 NM ELSEWHERE RADIUS OF 035 KT WINDS - 145 NM NORTH SEMICIRCLE 120 NM ELSEWHERE VECTOR TO 48 HR POSIT: 020 DEG/ 08 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 311200Z7 --- 19.9N9 117.6E5 MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT RADIUS OF 050 KT WINDS - 045 NM NORTH SEMICIRCLE 025 NM ELSEWHERE RADIUS OF 035 KT WINDS - 140 NM NORTH SEMICIRCLE 115 NM ELSEWHERE VECTOR TO 72 HR POSIT: 035 DEG/ 07 KTS --- 72 HRS, VALID AT: 011200Z4 --- 22.0N4 119.3E4 MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT RADIUS OF 050 KT WINDS - 030 NM NORTHEAST SEMICIRCLE 020 NM ELSEWHERE RADIUS OF 035 KT WINDS - 130 NM NORTHEAST SEMICIRCLE OVER WATER 115 NM ELSEWHERE --- REMARKS: 291500Z7 POSITION NEAR 16.1N8 117.7E6. TROPICAL STORM (TS) 30W (XANGSANE), LOCATED APPROXIMATELY 198 NM NORTHWEST OF MANILA, PHILIPPINES, HAS REMAINED QUASI-STATIONARY OVER THE PAST 06 HOURS. THE WARNING POSITION IS BASED ON 291130Z6 INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 55 KNOTS. A 290940Z4 SPECIAL SENSOR MICROWAVE IMAGER (SSM/I) PASS DEPICTED TWO RELATIVELY WEAK RAINBANDS TO THE NORTHWEST AND SOUTHEAST OF THE VORTEX. A STRONGER SPIRAL BAND EXISTS ABOUT 120 NM TO THE SOUTHWEST. OVERALL, THE CONVECTION HAS WEAKENED NEAR THE LLCC DURING THE PAST 4 HOURS. COOLER DRY AIR ADVECTION ANALYZED ON THE 850 OVER THE SOUTHEAST COAST OF CHINA/HAINAN ISLAND REGION CAN BE SEEN ON I/R ANIMATION DETERIORATING THE CONVECTION OVER THE WESTERN SEMI-CIRCLE. TS 30W IS FORECAST TO DRIFT WESTWARD THROUGH 12 HOURS. AFTERWARD, THE SYSTEM SHOULD TRACK INCREASINGLY NORTHWARD INTO THE WEAKNESS CREATED BY AN APPROACHING MID-LATITUDE TROUGH. TS 30W IS EXPECTED TO RE-INTENSIFY AT A CLIMATOLOGICAL RATE UNDER A GENERALLY FAVORABLE ENVIRONMENT. TS 30W SHOULD WEAKEN NEAR MID PERIOD AS IT TRACKS UNDER INCREASING VERTICAL WIND SHEAR ASSOCIATED WITH MODERATE LOW-LEVEL NORTHEASTERLIES AND RELATIVELY COOLER DRY AIR. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 291200Z4 IS 18 FEET. REFER TO WWPW31 RJTX FOR ADDITIONAL SEA HEIGHT INFORMATION. NEXT WARNINGS AT 292100Z4 (DTG 291952Z8), 300300Z6 (DTG 300152Z1), 300900Z2 (DTG 300752Z7) AND 301500Z9 (DTG 301352Z4).// NNNN