WTXS31 PGTW 030900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 012// RMKS/ 1. TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 012 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 030600Z --- NEAR 23.9S 114.3E MOVEMENT PAST SIX HOURS - 270 DEGREES AT 01 KTS POSITION ACCURATE TO WITHIN 030 NM POSITION BASED ON CENTER LOCATED BY A COMBINATION OF SATELLITE, RADAR AND SYNOPTIC DATA PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY REPEAT POSIT: 23.9S 114.3E --- FORECASTS: 12 HRS, VALID AT: 031800Z --- 24.0S 114.1E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY VECTOR TO 24 HR POSIT: 220 DEG/ 03 KTS --- 24 HRS, VALID AT: 040600Z --- 24.4S 113.7E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY VECTOR TO 36 HR POSIT: 235 DEG/ 03 KTS --- 36 HRS, VALID AT: 041800Z --- 24.7S 113.2E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 000 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 195 DEG/ 03 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 050600Z --- 25.3S 113.0E 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 050 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 175 DEG/ 07 KTS --- 72 HRS, VALID AT: 060600Z --- 28.0S 113.3E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 030900Z POSITION NEAR 23.9S 114.2E. 03FEB21. TROPICAL CYCLONE (TC) 18S (EIGHTEEN), LOCATED APPROXIMATELY 97 NM SOUTH OF LEARMONTH, AUSTRALIA, HAS TRACKED WESTWARD AT 01 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS SPIRAL BANDS OF DEEP CONVECTION WRAPPING INTO AN OBSCURED LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON TIMELY IMAGERY FROM A 030614Z ATMS PASS AND THE WELL DEFINED RAIN BANDS EVIDENT IN THE COMPOSITE RADAR LOOP FROM LEARMONTH. THE INITIAL INTENSITY IS ASSESSED AT 30 KTS BASED ON EXTRAPOLATION OF MULTIPLE SURFACE OBSERVATIONS WITH FAIR CONFIDENCE. TC 18S IS TRACKING THROUGH A WEAK STEERING ENVIRONMENT CHARACTERIZED BY LOW (5-10 KTS) VERTICAL WIND SHEAR (VWS) AND ROBUST POLEWARD AND EQUATORWARD OUTFLOW ALOFT. IN THE NEAR TERM, A SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTHEAST WILL BUILD AND BEGIN TO DRIVE THE SYSTEM INITIALLY WESTWARD AND THEN SOUTHWESTWARD INTO THE WARM WATERS OF THE INDIAN OCEAN. THESE WARM (26-27 CELSIUS) SEA SURFACE TEMPERATURES (SST), COUPLED WITH CONTINUED LOW VWS AND SUPPORTIVE UPPER LEVEL DIVERGENCE WILL LEAD TO GRADUAL INTENSIFICATION TO 35 KTS BY TAU 36. THEREAFTER, INCREASING VWS AND COOLING SST AFTER TAU 48 WILL LEAD TO DISSIPATION OVER WATER BY TAU 72. NUMERICAL MODEL GUIDANCE IS IN FAIR AGREEMENT WITH A MAXIMUM SPREAD IN SOLUTIONS OF 112 NM AT TAU 72 AND LENDS OVERALL FAIR AGREEMENT IN THE JTWC FORECAST TRACK WHICH IS PLACED ON THE MULTI- MODEL CONSENSUS. NEXT WARNINGS AT 031500Z, 032100Z, 040300Z AND 040900Z. // NNNN