WTXS31 PGTW 241500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 13S (THIRTEEN) WARNING NR 008// RMKS/ 1. TROPICAL CYCLONE 13S (THIRTEEN) WARNING NR 008 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 241200Z --- NEAR 16.1S 96.2E MOVEMENT PAST SIX HOURS - 270 DEGREES AT 04 KTS POSITION ACCURATE TO WITHIN 040 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY REPEAT POSIT: 16.1S 96.2E --- FORECASTS: 12 HRS, VALID AT: 250000Z --- 16.7S 95.6E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY VECTOR TO 24 HR POSIT: 210 DEG/ 04 KTS --- 24 HRS, VALID AT: 251200Z --- 17.4S 95.2E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 000 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 210 DEG/ 04 KTS --- 36 HRS, VALID AT: 260000Z --- 18.0S 94.8E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 000 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 250 DEG/ 04 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 261200Z --- 18.3S 94.0E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 000 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 275 DEG/ 07 KTS --- 72 HRS, VALID AT: 271200Z --- 18.0S 91.2E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 030 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 280 DEG/ 11 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 281200Z --- 17.0S 86.5E 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 - 000 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT VECTOR TO 120 HR POSIT: 285 DEG/ 14 KTS --- 120 HRS, VALID AT: 291200Z --- 15.4S 80.7E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 241500Z POSITION NEAR 16.3S 96.1E. 24JAN21. TROPICAL CYCLONE (TC) 13S (THIRTEEN), LOCATED APPROXIMATELY 244 NM SOUTH OF COCOS ISLANDS, AUSTRALIA, HAS TRACKED WESTWARD AT 04 KNOTS (KTS) OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) REVEALS THAT THE ASSOCIATED CONVECTION FOR TC 13S HAS STRUGGLED OVER THE PAST SIX HOURS AS IT CONTINUES TO FLARE OVER TOP OF THE LOW LEVEL CIRCULATION (LLC). THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE BASED ON LOW CLOUD TRACING IN THE MSI AND FRAGMENTED CONVECTIVE BANDING IN A 241249Z SSMIS 91 GHZ MICROWAVE IMAGE. ADDITIONALLY, THIS POSITION IS IN GOOD AGREEMENT WITH THE PGTW FIX SITE. THE INITIAL INTENSITY OF 30 KTS IS BASED ON A PGTW DVORAK CURRENT INTENSITY ESTIMATE OF T2.0 (30 KTS) AND THE FLARING CONVECTION. TC 13S IS TRANSITING THROUGH A MARGINALLY FAVORABLE ENVIRONMENT CHARACTERIZED BY MODERATE (20 KTS) VERTICAL WIND SHEAR (VWS) OFFSET BY IMPROVING WESTWARD AND POLEWARD UPPER LEVEL OUTFLOW CHANNELS AND MILDLY CONDUCIVE (27 CELSIUS) SEA SURFACE TEMPERATURES (SST). THE SYSTEM IS TRACKING ALONG AN EXTENSION OF THE NEAR EQUATORIAL RIDGE POSITIONED TO THE EAST AND IS EXPECTED TO CONTINUE ALONG THIS PERIPHERY THROUGH TAU 36 WHEN A SUBTROPICAL RIDGE TO THE SOUTHWEST WILL BUILD IN AND BECOME THE PRIMARY STEERING MECHANISM. UNDER THIS NEW INFLUENCE, THE SYSTEM WILL TRACK WESTWARD THEN WEST- NORTHWESTWARD FOR THE REMAINDER OF THE FORECAST PERIOD. IN THE NEAR TERM, INTENSIFICATION WILL BE LIMITED DUE TO THE CURRENT ENVIRONMENTAL CONDITIONS. HOWEVER, AS THE VWS DECREASES AND THE SYSTEM BEGINS TO MOVE IN-PHASE WITH THE UPPER LEVEL FLOW, TC 13S IS FORECAST TO GRADUALLY INTENSIFY TO A PEAK OF 40 KTS BY TAU 36. AFTERWARD, COOLING SST WILL LEAD TO A STEADY WEAKENING WITH DISSIPATION EXPECTED NEAR TAU 120 AS THE SYSTEM BEGINS TO ENCOUNTER INCREASING VWS. NUMERICAL MODELS ARE IN GOOD AGREEMENT, PLACING FAIR CONFIDENCE TO THE JTWC TRACK FORECAST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 241200Z IS 12 FEET. NEXT WARNINGS AT 250300Z AND 251500Z.// NNNN