WTXS31 PGTW 150300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE WARNING// REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/140851ZSEP2018// AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.// RMKS/ 1. TROPICAL CYCLONE 01S (ONE) 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: 150000Z --- NEAR 9.9S 72.1E MOVEMENT PAST SIX HOURS - 260 DEGREES AT 07 KTS POSITION ACCURATE TO WITHIN 045 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 - 000 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT REPEAT POSIT: 9.9S 72.1E --- FORECASTS: 12 HRS, VALID AT: 151200Z --- 10.3S 70.3E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 005 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 035 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 255 DEG/ 11 KTS --- 24 HRS, VALID AT: 160000Z --- 10.8S 68.2E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 005 NM NORTHEAST QUADRANT 045 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 255 DEG/ 12 KTS --- 36 HRS, VALID AT: 161200Z --- 11.5S 65.9E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 005 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 025 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 260 DEG/ 10 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 170000Z --- 11.9S 63.8E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 000 NM NORTHEAST QUADRANT 000 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 280 DEG/ 12 KTS --- 72 HRS, VALID AT: 180000Z --- 11.1S 58.9E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 000 NM NORTHEAST QUADRANT 000 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 300 DEG/ 17 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 190000Z --- 7.9S 53.0E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 150300Z POSITION NEAR 10.0S 71.7E. TROPICAL CYCLONE (TC) 01S (ONE), LOCATED APPROXIMATELY 170 NM SOUTH OF DIEGO GARCIA, HAS TRACKED WESTWARD AT 07 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS FLARING CONVECTION WRAPPING AROUND THE LOW LEVEL CIRCULATION CENTER. THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE USING A COMBINATION OF THE EIR IMAGERY AND A 142250Z SSMIS 37 GHZ MICROWAVE IMAGE WHICH SHOWS CONVECTION WRAPPING CYCLONICALLY AROUND A LOW BRIGHTNESS TEMPERATURE REGION. THE INITIAL INTENSITY OF 35 KTS IS BASED ON THE PGTW DVORAK CURRENT INTENSITY ESTIMATE OF T2.5 (35 KTS). TC 01S IS IN A MARGINALLY FAVORABLE ENVIRONMENT WITH MODERATE VERTICAL WIND SHEAR AND GOOD POLEWARD OUTFLOW. SEA SURFACE TEMPERATURES ARE MARGINAL AT 26 CELSIUS. THE CYCLONE IS BEING STEERED BY A SUBTROPICAL RIDGE (STR) TO THE SOUTHEAST WHICH WILL CONTINUE TO STEER 01S WESTWARD TO WEST-SOUTHWESTWARD THROUGH TAU 48. AFTER TAU 48, A STR TO THE SOUTHWEST WILL BECOME THE PRIMARY STEERING MECHANISM AND THE TRACK WILL SHIFT NORTHWESTWARD. THROUGHOUT THE FORECAST, SST CONDITIONS WILL BE MARGINAL AND THE INTENSITY IS EXPECTED TO LINGER AROUND 35 KTS. UNCERTAINTY IN THE NUMERICAL MODEL GUIDANCE IS VERY HIGH, WITH A SPREAD OF OVER 300 NM BY TAU 72, THEREFORE CONFIDENCE IN THE JTWC FORECAST TRACK IS LOW. SIGNIFICANT WAVE HEIGHT AT 150000Z IS 8 FEET. NEXT WARNINGS AT 150900Z, 151500Z AND 152100Z. 2. THIS CANCELS AND SUPERSEDES REF A (WTXS21 PGTW 140900).// NNNN