SUBJ: TROPICAL CYCLONE WARNING WTPN31 PGTW 280900 1. TROPICAL STORM 11W (BOLAVEN) WARNING NR 015 02 ACTIVE TROPICAL CYCLONES IN NORTHWESTPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 280600Z6 --- NEAR 28.0N0 129.0E2 MOVEMENT PAST SIX HOURS - 330 DEGREES AT 06 KTS POSITION ACCURATE TO WITHIN 045 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT RADIUS OF 035 KT WINDS - 090 NM EAST SEMICIRCLE 045 NM ELSEWHERE REPEAT POSIT: 28.0N0 129.0E2 --- FORECASTS: 12 HRS, VALID AT: 281800Z9 --- 29.2N3 128.4E5 MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT RADIUS OF 050 KT WINDS - 025 NM NORTHEAST SEMICIRCLE 015 NM ELSEWHERE RADIUS OF 035 KT WINDS - 095 NM NORTHEAST SEMICIRCLE 050 NM ELSEWHERE VECTOR TO 24 HR POSIT: 350 DEG/ 07 KTS --- 24 HRS, VALID AT: 290600Z7 --- 30.6N9 128.1E2 MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT RADIUS OF 050 KT WINDS - 025 NM NORTHEAST SEMICIRCLE 015 NM ELSEWHERE RADIUS OF 035 KT WINDS - 095 NM NORTHEAST SEMICIRCLE 050 NM ELSEWHERE VECTOR TO 36 HR POSIT: 360 DEG/ 08 KTS --- 36 HRS, VALID AT: 291800Z0 --- 32.3N8 128.2E3 MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT RADIUS OF 035 KT WINDS - 090 NM NORTHEAST SEMICIRCLE OVER WATER 045 NM ELSEWHERE VECTOR TO 48 HR POSIT: 015 DEG/ 11 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 300600Z9 --- 34.5N2 128.8E9 MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT RADIUS OF 035 KT WINDS - 075 NM EAST SEMICIRCLE OVER WATER 035 NM ELSEWHERE VECTOR TO 72 HR POSIT: 025 DEG/ 16 KTS --- 72 HRS, VALID AT: 310600Z0 --- 40.1N5 132.6E2 MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 280900Z9 POSITION NEAR 28.3N3 128.8E9. TROPICAL STORM (TS) 11W (BOLAVEN), LOCATED APPROXIMATELY 310 NM SOUTH OF SASEBO, JAPAN, HAS TRACKED NORTH-NORTHWEST AT 06 KNOTS DURING THE PAST 6 HOURS. THE WARNING POSITION IS BASED ON 280530Z8 VISIBLE AND INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 45 AND 55 KNOTS, AND SYNOPTIC REPORTS. ANIMATED VISIBLE SATELLITE IMAGERY DEPICTS A FULLY-EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH CONVECTION SHEARED ABOUT 58 NM SOUTH OF THE LLCC. ANIMATED WATER VAPOR IMAGERY INDICATES THAT THE TROPICAL UPPER TROPOSPHERIC LOW HAS MOVED RAPIDLY NORTHEAST OVER THE PAST 6 HOURS AND IS NOW SITUATED AT 28.0N0 143.3E1. CONSEQUENTLY, OUTFLOW ON THE EASTERN SIDE OF TS 11W HAS IMPROVED. TS 11W (BOLAVEN) IS FORECAST TO TRACK GENERALLY NORTH- NORTHWESTWARD THROUGH THE NEXT 24 HOURS. AFTERWARD, THE TUTT TO THE EAST WILL WEAKEN AND SHIFT NORTHEAST ALLOWING THE MID-LEVEL HIGH EAST OF THE MARIANA ISLANDS TO BUILD OVER CENTRAL JAPAN. THIS WILL CAUSE TS 11W TO ACCELERATE AND TURN MORE NORTHWARD TO NORTH- NORTHEASTWARD AFTER 36 HOURS. THE SYSTEM IS FORECAST TO MAINTAIN INTENSITY THROUGH 24 HOURS, THEN BEGIN WEAKENING AS IT TRACKS UNDER AN INCREASINGLY UNFAVORABLE ENVIRONMENT. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 280600Z6 IS 18 FEET. REFER TO WWPW30 RJTX FOR ADDITIONAL SEA HEIGHT INFORMATION. NEXT WARNINGS AT 281500Z6 (DTG 281351Z0), 282100Z3 (DTG 281951Z6), 290300Z4 (DTG 290151Z8) AND 290900Z0 (DTG 290751Z4). REFER TO TROPICAL DEPRESSION 12W (NONAME) WARNINGS (WTPN32 PGTW) FOR SIX-HOURLY UPDATES.// BT #XXXX NNNN