WTXS32 PGTW 071500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 27S (TWENTYSEVEN) WARNING NR 011// RMKS/ 1. TROPICAL CYCLONE 27S (TWENTYSEVEN) WARNING NR 011 02 ACTIVE TROPICAL CYCLONES IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 071200Z --- NEAR 16.2S 106.2E MOVEMENT PAST SIX HOURS - 090 DEGREES AT 04 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT REPEAT POSIT: 16.2S 106.2E --- FORECASTS: 12 HRS, VALID AT: 080000Z --- 15.6S 106.8E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 040 DEG/ 05 KTS --- 24 HRS, VALID AT: 081200Z --- 14.9S 107.4E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 060 DEG/ 10 KTS --- 36 HRS, VALID AT: 090000Z --- 13.9S 109.2E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 115 DEG/ 11 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 091200Z --- 14.9S 111.3E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 165 DEG/ 15 KTS --- 72 HRS, VALID AT: 101200Z --- 20.6S 112.7E 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 - 100 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 180 DEG/ 10 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 111200Z --- 24.7S 112.7E MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 071500Z POSITION NEAR 16.0S 106.4E. 07APR21. TROPICAL CYCLONE 27S (TWENTYSEVEN), LOCATED APPROXIMATELY 578 NM NORTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED EASTWARD AT 04 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS DEEP CONVECTION ONCE AGAIN FLARING NEAR THE CORE OF THE SYSTEM, AND OBSCURING THE LOW LEVEL CIRCULATION CENTER (LLCC). THE BULK OF THE CONVECTION REMAINS SHEARED TO THE SOUTHWEST UNDER MODERATE NORTHEASTERLY VERTICAL WIND SHEAR (VWS). A TIMELY 071141Z SSMIS 91GHZ MICROWAVE IMAGE CAPTURED THE INITIAL STAGES OF THE SURGE IN CONVECTION AND SHOWED WEAK LOW LEVEL BANDS WRAPPING INTO A POORLY DEFINED CENTER, LENDING MODERATE CONFIDENCE TO THE INITIAL POSITION. THE INITIAL INTENSITY REMAINS SET AT 40 KNOTS WITH MODERATE CONFIDENCE BASED ON AN BLEND OF A PGTW DVORAK INTENSITY ESTIMATE OF T2.5 (35 KTS), AN APRF ESTIMATE OF T3.0 (45 KTS), AN ADT ESTIMATE OF T2.5 AND A SATCON OF 43 KTS. OVER THE PAST SIX HOURS, TC 27S HAS DRIFTED SLOWLY EASTWARD, BUT IN THE NEAR-TERM THE SYSTEM IS EXPECTED TO TAKE ON A MORE NORTHEASTWARD TRACK, THOUGH THE OVERALL STEERING ENVIRONMENT REMAINS RELATIVELY WEAK THROUGH TAU 12. BY TAU 24 TC 27S WILL MOVE TO WITHIN 330NM OF TC 26S, BE CAPTURED BY TC 26S AND BEGIN BINARY INTERACTION. ONCE THE SYSTEM IS CAPTURED IT WILL ACCELERATE ONTO A NORTHEAST, THEN EAST AND ULTIMATELY SOUTHWARD TRACK, MOVING PROGRESSIVELY CLOSER TO TC 26S AND ULTIMATELY MERGING WITH IT NO LATER THAN TAU 96. MODERATE EAST-NORTHEAST SHEAR IS EXPECTED TO CONTINUE FOR THE NEXT 12-18 HOURS, WHICH WILL INHIBIT NEAR-TERM INTENSIFICATION. ONCE THE SYSTEM STARTS TO MOVE NORTH AND OUT FROM UNDER THE OUTFLOW EMANATING FROM TC 26S, IT WILL EXPERIENCE REDUCED SHEAR AND MAY FOR A SHORT TIME DEVELOP ITS OWN OUTFLOW ALOFT, ALLOWING FOR A SHORT BURST OF INTENSIFICATION THROUGH TAU 48. AFTER STARTING ITS DIVE SOUTHWARD AFTER TAU 48, THE COMBINATION OF INCREASINGLY CONVERGENCE OUTFLOW, INCREASING SHEAR AND DISRUPTION OF THE LOW LEVEL WIND FIELD DUE TO INTERACTION WITH TC 26S, IT WILL BEGIN TO RAPIDLY WEAKEN PRIOR TO MERGER WITH TC 26S. NUMERICAL MODEL GUIDANCE IS IN GENERAL AGREEMENT ON THE OVERALL SCENARIO AND HAS REMAINED RELATIVELY CONSISTENT OVER THE PREVIOUS TWO RUNS, LENDING INCREASING CONFIDENCE IN THE SCENARIO. HOWEVER, GUIDANCE STILL REFLECTS A HIGH DEGREE OF UNCERTAINTY, PARTICULARLY IN HOW CLOSE THE TRACK OF THE REMNANTS OF TC 27S WILL APPROACH THE COASTLINE. THE JTWC FORECAST TRACK LIES CLOSE TO THE CONSENSUS MEAN BUT IN LIGHT OF THE SPREAD IN THE POTENTIAL TRACK SOLUTIONS, THERE REMAINS OVERALL LOW CONFIDENCE IN THE FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 071200Z IS 18 FEET. NEXT WARNINGS AT 072100Z, 080300Z, 080900Z AND 081500Z. REFER TO TROPICAL CYCLONE 26S (SEROJA) WARNINGS (WTXS31 PGTW) FOR SIX-HOURLY UPDATES. NNNN