WTXS31 PGTW 270300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 17S (SEVENTEEN) WARNING NR 001// REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/260251ZAPR2017// AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.// RMKS/ 1. TROPICAL CYCLONE 17S (SEVENTEEN) WARNING NR 001 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 270000Z --- NEAR 9.6S 130.2E MOVEMENT PAST SIX HOURS - 225 DEGREES AT 08 KTS POSITION ACCURATE TO WITHIN 020 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 045 NM NORTHEAST QUADRANT 065 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT REPEAT POSIT: 9.6S 130.2E --- FORECASTS: 12 HRS, VALID AT: 271200Z --- 10.2S 128.9E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 105 NM SOUTHEAST QUADRANT 095 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 245 DEG/ 08 KTS --- 24 HRS, VALID AT: 280000Z --- 10.8S 127.5E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 045 NM NORTHEAST QUADRANT 110 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 245 DEG/ 09 KTS --- 36 HRS, VALID AT: 281200Z --- 11.6S 125.9E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 015 NM NORTHEAST QUADRANT 110 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 245 DEG/ 07 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 290000Z --- 12.2S 124.6E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 015 NM NORTHEAST QUADRANT 085 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 245 DEG/ 05 KTS --- 72 HRS, VALID AT: 300000Z --- 13.0S 122.6E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 034 KT WINDS - 015 NM NORTHEAST QUADRANT 065 NM SOUTHEAST QUADRANT 035 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 255 DEG/ 04 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 010000Z --- 13.4S 121.1E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 270300Z POSITION NEAR 9.7S 129.9E. TROPICAL CYCLONE (TS) 17S (SEVENTEEN), LOCATED APPROXIMATELY 179 NM NORTH-NORTHWEST OF DARWIN, AUSTRALIA, HAS TRACKED SOUTHWESTWARD AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) WITH DEEP FLARING CONVECTION ALONG THE SOUTHERN PERIPHERY. A 270102Z ASCAT BULLSEYE SHOWS A DEFINED LLCC WITH 35 KNOT WINDS ALONG THE SOUTHERN SIDE WRAPPING INTO THE CENTER. THE CURRENT POSITION AND INTENSITY ARE BASED ON THE SCATTEROMETER PASS WITH HIGH CONFIDENCE. ENVIRONMENTAL CONDITIONS ARE FAVORABLE WITH LOW TO MODERATE VERTICAL WIND SHEAR, STRONG DIVERGENT OUTFLOW AND WARM SEA SURFACE TEMPERATURES. TS 17S IS TRACKING ALONG THE NORTHERN PERIPHERY OF AN EXTENSION OF THE SUB-TROPICAL RIDGE LOCATED TO THE EAST. THE FAVORABLE ENVIRONMENT WILL SUPPORT A PERIOD OF INTENSIFICATION OVER THE NEXT 24 HOURS AS THE CYCLONE TRACKS WESTWARD. AFTERWARDS, INCREASING VWS WILL BEGIN TO WEAKEN THE CYCLONE AND LEAD TO ITS COMPLETE DISSIPATION BY THE END OF THE FORECAST PERIOD. AVAILABLE MODEL GUIDANCE IS IN PRETTY GOOD AGREEMENT OVER THE FIRST 36 HOURS BUT BEGIN TO DIVERGE AS THE CYCLONE WEAKENS. THIS DIVERGENCE IN GUIDANCE LENDS LOW CONFIDENCE IN THE JTWC FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 270000Z IS 10 FEET. NEXT WARNINGS AT 271500Z AND 280300Z. THIS CANCELS AND SUPERSEDES REF A (WTXS21 PGTW 260300).//