WTXS31 PGTW 031500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 013// RMKS/ 1. TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 013 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 031200Z --- NEAR 23.9S 114.5E MOVEMENT PAST SIX HOURS - 090 DEGREES AT 02 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 114.5E --- FORECASTS: 12 HRS, VALID AT: 040000Z --- 24.1S 114.1E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY VECTOR TO 24 HR POSIT: 230 DEG/ 03 KTS --- 24 HRS, VALID AT: 041200Z --- 24.5S 113.6E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY VECTOR TO 36 HR POSIT: 215 DEG/ 03 KTS --- 36 HRS, VALID AT: 050000Z --- 25.0S 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 045 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 195 DEG/ 04 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 051200Z --- 25.7S 113.0E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 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 090 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 010 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 170 DEG/ 08 KTS --- 72 HRS, VALID AT: 061200Z --- 28.8S 113.5E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 031500Z POSITION NEAR 24.0S 114.4E. 03FEB21. TROPICAL CYCLONE (TC) 18S (EIGHTEEN), LOCATED APPROXIMATELY 99 NM SOUTH-SOUTHEAST OF LEARMONTH, AUSTRALIA, HAS TRACKED EASTWARD AT 02 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A COMPACT SYSTEM WITH SPIRAL BANDS OF DEEP CONVECTION WRAPPING INTO AN OBSCURED LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE CONVECTIVE FEATURES IN A 030928Z SSMIS 91 GHZ IMAGE 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 GENERALLY SOUTHWESTWARD. AS THE SYSTEM MOVES OVER THE WARM WATERS OF THE INDIAN OCEAN BY TAU 36, WARM (26-27 CELSIUS) SEA SURFACE TEMPERATURES (SST), LOW VWS AND SUPPORTIVE UPPER LEVEL DIVERGENCE WILL LEAD TO GRADUAL INTENSIFICATION. BY TAU 48, TC 18W WILL REACH A PEAK INTENSITY OF 40 KTS AND BEGIN A POLEWARD TRACK AS IT ROUNDS THE AXIS OF THE STEERING STR. AT THIS TIME, TC 18S WILL BEGIN TO DISSIPATE OVER WATER DUE TO HIGH (20-25 KTS) VWS. BY TAU 72, HIGH (30+ KTS) VWS WILL LEAD TO FULL DISSIPATION OVER WATER. NUMERICAL MODEL GUIDANCE IS IN FAIR AGREEMENT WITH A MAXIMUM SPREAD IN SOLUTIONS OF 120 NM AT TAU 72 AND LENDS OVERALL FAIR CONFIDENCE IN THE JTWC FORECAST TRACK WHICH IS PLACED ON THE MULTI-MODEL CONSENSUS. NEXT WARNINGS AT 032100Z, 040300Z, 040900Z AND 041500Z. // NNNN