WTXS32 PGTW 081500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 27S (TWENTYSEVEN) WARNING NR 015A AMENDED// RMKS/ 1. TROPICAL CYCLONE 27S (TWENTYSEVEN) WARNING NR 015A AMENDED 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 050 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 - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 081500Z POSITION NEAR 14.9S 106.2E. 08APR21. TROPICAL CYCLONE 27S (TWENTYSEVEN), LOCATED APPROXIMATELY 628 NM NORTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED NORTHWESTWARD AT 07 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY(MSI) SHOWS THE SYSTEM HAS MOSTLY MAINTAINED CONVECTIVE SIGNATURE ON THE WESTERN SIDE AS TC 27S MOVED SLIGHTLY NORTHWEST IN THE WEAK STEERING ENVIRONMENT. THE MAIN CONVECTION REMAINS SHEARED WESTWARD OF A PARTLY-EXPOSED LOW LEVEL CIRCULATION. THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE BASED USING A 080725Z GMI 89GHZ MICROWAVE IMAGE AND THE MSI LOOP. THE INITIAL INTENSITY OF 35KTS IS HEDGED HIGHER THAN MULTIPLE DVORAK AGENCY FIXES OF T2.0(30KTS) AND MORE IN LINE WITH THE ADT ESTIMATE OF T2.2/32KTS, AND SATELLITE CONSENSUS(SATCON) OF 36KTS. ANALYSIS INDICATES THE CYCLONE IS IN A MARGINAL ENVIRONMENT WITH STRONG 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 IS 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 350NM TO THE EAST. AS TC 26S GETS CLOSER, A BINARY INTERACTION WILL COMMENCE DUE TO FUJIWARA EFFECT RESULTING IN TC 26S TRACKING CYCLONICALLY INTO AN ARC NORTHEASTWARD. THE WARM WATER AND INCREASED OUTFLOW WILL MARGINALLY OFFSET THE VWS AND PROMOTE A MODEST INTENSIFICATION TO A PEAK OF 50KTS AS IT CRESTS THE ARC. AFTERWARD, IT WILL RAPIDLY DECAY AS IT GETS RAPIDLY ABSORBED INTO THE LARGER AND MUCH MORE DOMINANT TC 26S LEADING TO DISSIPATION BY TAU 36, POSSIBLY SOONER. THE NUMERICAL MODELS ARE IN FAIR AGREEMENT WITH AFUM A SEVERE OUTLIER TO THE RIGHT AFTER TAU 24. ALL OTHER MODELS ARE IN TIGHT AGREEMENT UNTIL TAU 36 AS THE COMPLEX DYNAMICS OF THE BINARY INTERACTION BEGINS, THERE IS LOW CONFIDENCE IN THE JTWC TRACK FORECAST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 080600Z IS 16 FEET. NEXT WARNINGS AT 081500Z, 082100Z, 090300Z AND 090900Z. REFER TO TROPICAL CYCLONE 26S (SEROJA) WARNINGS (WTXS31 PGTW) FOR SIX-HOURLY UPDATES.// NNNN