WTPS31 PGTW 151500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 30P (TAM) WARNING NR 006// RMKS/ 1. TROPICAL CYCLONE 30P (TAM) WARNING NR 006 01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 151200Z --- NEAR 23.1S 171.7E MOVEMENT PAST SIX HOURS - 160 DEGREES AT 23 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING SUBTROPICAL RADIUS OF 050 KT WINDS - 100 NM NORTHEAST QUADRANT 075 NM SOUTHEAST QUADRANT 000 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 215 NM NORTHEAST QUADRANT 180 NM SOUTHEAST QUADRANT 000 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT REPEAT POSIT: 23.1S 171.7E --- FORECASTS: 12 HRS, VALID AT: 160000Z --- 28.6S 171.9E MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT WIND RADII VALID OVER OPEN WATER ONLY SUBTROPICAL RADIUS OF 050 KT WINDS - 100 NM NORTHEAST QUADRANT 110 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 010 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 230 NM NORTHEAST QUADRANT 220 NM SOUTHEAST QUADRANT 300 NM SOUTHWEST QUADRANT 125 NM NORTHWEST QUADRANT --- REMARKS: 151500Z POSITION NEAR 24.5S 171.7E. 15APR25. TROPICAL CYCLONE 30P (TAM), LOCATED APPROXIMATELY 316 NM EAST-SOUTHEAST OF NOUMEA, NEW CALEDONIA, HAS TRACKED SOUTH- SOUTHEASTWARD AT 23 KNOTS OVER THE PAST SIX HOURS. TROPICAL CYCLONE (TC) 30S (TAM), WHILE STEADILY INCREASING IN INTENSITY, IS DOING SO UNDER THE AUSPICES OF INCREASING BAROCLINIC FORCING AS IT RAPIDLY UNDERGOES SUBTROPICAL TRANSITION (STT). THE SYSTEM IS TRACKING SOUTHEASTWARD AT A VERY FAST 23 KNOTS, ALONG THE WESTERN SIDE OF A DEEP-LAYER SUBTROPICAL TO THE EAST. OVER THE NEXT 12 TO 24 HOURS, TEH SYSTEM WILL BEGIN TO TRACK MORE SOUTHWARD, EVENTUALLY TURNING SOUTHWESTWARD AS IT UNDERGOES BINARY INTERACTION WITH A RAPIDLY DEVELOPING LOW PRESSURE AREA CURRENTLY JUST SOUTHWEST OF NEW CALEDONIA. TC 30S PRESENTS AN IMPRESSIVE SIGNATURE IN THE ENHANCED INFRARED (EIR) IMAGERY, WITH EXTREMELY COLD OVERSHOOTING TOPS APPORACHING -90C. HOWEVER, THE VORTEX IS DECOUPLED AND THE LOW-LEVEL CIRCULATION CENTER (LLCC) IS DISPLACED OVER 60NM TO THE NORTHWEST FROM THE COLDEST CLOUD TOPS. A LACK OF RECENT MICROWAVE IMAGERY PRECLUDES A HIGH CONFIDENCE ASSESSMENT, THOUGH A 151004Z AMSU-B 89GHZ IMAGE PROVIDED ENOUGH EVIDENCE OF THE VORTEX DECOUPLING TO LEND HIGH MEDIUM CONFIDENCE TO THE INITIAL POSITION. THE INITIAL INTENSITY IS BASED ON THE T3.5 FIXES FROM BOTH PGTW AND KNES, WITH MEDIUM CONFIDENCE. THE SYSTEM IS FORECAST TO CONTINUE TO INTENSIFY OVER THE NEXT 12 HOURS WHILE UNDERGOING STT. TC 30S WILL PASS SOUTH OF THE 26C ISOTHERM WITHIN THE NEXT SIX HOURS OR SO, AND MOVE UNDER THE NOSE OF A 100 KNOT SUBTROPICAL JET MAX WHILE DEVELOPING INCREASING BAROCLINICTY. THE SYSTEM IS EXPECTED TO COMPLETE THE STT PROCESS BY TAU 12, CONVERTING TO A STORM-FORCE LOW PRESSURE SYSTEM NORTHWEST OF NEW ZEALAND. THIS IS THE FINAL WARNING ON THIS SYSTEM BY THE JOINT TYPHOON WRNCEN PEARL HARBOR HI. THE SYSTEM WILL BE CLOSELY MONITORED FOR SIGNS OF REGENERATION. MINIMUM CENTRAL PRESSURE AT 151200Z IS 986 MB. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 151200Z IS 31 FEET.// NNNN