WTXS32 PGTW 081500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 27S (TWENTYSEVEN) WARNING NR 015// RMKS/ 1. TROPICAL CYCLONE 27S (TWENTYSEVEN) WARNING NR 015 02 ACTIVE TROPICAL CYCLONES IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 081200Z --- NEAR 15.0S 105.7E MOVEMENT PAST SIX HOURS - 010 DEGREES AT 06 KTS POSITION ACCURATE TO WITHIN 060 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 - 055 NM NORTHEAST QUADRANT 035 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT REPEAT POSIT: 15.0S 105.7E --- FORECASTS: 12 HRS, VALID AT: 090000Z --- 14.6S 107.5E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT 075 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 120 DEG/ 14 KTS --- 24 HRS, VALID AT: 091200Z --- 16.0S 110.0E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT 075 NM SOUTHEAST QUADRANT 105 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 155 DEG/ 14 KTS --- 36 HRS, VALID AT: 100000Z --- 18.4S 111.3E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT 055 NM SOUTHEAST QUADRANT 075 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT --- REMARKS: 081500Z POSITION NEAR 14.9S 106.2E. 08APR21. TROPICAL CYCLONE 27S (TWENTYSEVEN), LOCATED APPROXIMATELY 648 NM NORTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED NORTHWARD AT 06 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY(EIR) INDICATES A DECREASE IN OVERALL SIZE OF THE SYSTEM WITH ONLY A SMALL REGION OF CONVECTION REMAINING ON THE SOUTHERN SIDE. TC 27S IS CURRENTLY BEING ABSORBED INTO THE NORTHWESTERN PORTION OF TC 26S AND WILL CONTINUE LOSING MORE OF ITS CONVECTIVE STRUCTURE AS IT WRAPS ALONG THE NORTHERN PORTION OF TC 26S DURING THE NEXT COUPLE DAYS. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE USING A 081128Z SSMIS 91GHZ MICROWAVE IMAGE AND THE EIR LOOP. THE INITIAL INTENSITY OF 35KTS IS HEDGED SLIGHTLY HIGHER THAN DVORAK AGENCY FIX FROM PGTW OF T2.0(30KTS) AND MORE IN LINE WITH APRF, THE ADT ESTIMATE OF T2.5/35KTS, AND SATELLITE CONSENSUS (SATCON) OF 36KTS. ANALYSIS INDICATES THE CYCLONE IS IN A MARGINAL ENVIRONMENT WITH MODERATE SUBSIDENCE ALOFT ALONG THE EASTERN HALF DUE TO THE OUTFLOW FROM TC 26S AND MODERATE TO STRONG (20-25KT) EASTERLY VERTICAL WIND SHEAR THAT ARE PARTLY OFFSET BY WARM (29C) SEA SURFACE TEMPERATURE. THE SYSTEM REMAINS IN A NEUTRAL AREA BETWEEN A LOW REFLECTION OF THE SUBTROPICAL RIDGE TO THE SOUTHWEST, WEAK NEAR EQUATORIAL RIDGING TO THE NORTHWEST, AND OUTFLOW PRESSURE FROM AN APPROACHING TC 26S, CURRENTLY 340NM TO THE EAST. BINARY INTERACTION IS LIKELY TO BEGIN WITHIN THE NEXT 12 TO 24 HOURS WITH THE FUJIWARA EFFECT RESULTING IN TC 27S TRACKING CYCLONICALLY AROUND IN A NORTHEASTWARD ARC. WARM WATER AND INCREASED OUTFLOW IS EXPECTED TO MARGINALLY OFFSET THE VWS AND PROMOTE A MODEST INTENSIFICATION TO A PEAK OF 45KTS BY TAU 24 NEAR THE CREST OF THE ARC. AFTERWARD, IT WILL RAPIDLY DECAY AS IT GETS ABSORBED INTO THE MORE DOMINANT TC 26S, LEADING TO COMPLETE DISSIPATION BY TAU 36, POSSIBLY SOONER. THE NUMERICAL MODELS ARE IN FAIR AGREEMENT WITH AFUM REMAINING THE STRICT RIGHT OUTLIER TAU 12 AND BEYOND. ALL OTHER MODELS ARE IN FAIR AGREEMENT UNTIL TAU 36 WHERE THE COMPLEX DYNAMICS OF THE TIMING OF THE BINARY INTERACTION CONCLUDES, LENDING TO LOW CONFIDENCE IN THE JTWC TRACK FORECAST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 081200Z IS 17 FEET. NEXT WARNINGS AT 082100Z, 090300Z, 090900Z AND 091500Z. REFER TO TROPICAL CYCLONE 26S (SEROJA) WARNINGS (WTXS31 PGTW) FOR SIX-HOURLY UPDATES.// NNNN