WTPS32 PGTW 151500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 06P (ZAZU) WARNING NR 009// RMKS/ 1. TROPICAL CYCLONE 06P (ZAZU) WARNING NR 009 02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 151200Z --- NEAR 19.6S 172.4W MOVEMENT PAST SIX HOURS - 120 DEGREES AT 13 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 RADIUS OF 050 KT WINDS - 070 NM NORTHEAST QUADRANT 065 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 180 NM NORTHEAST QUADRANT 095 NM SOUTHEAST QUADRANT 110 NM SOUTHWEST QUADRANT 105 NM NORTHWEST QUADRANT REPEAT POSIT: 19.6S 172.4W --- FORECASTS: 12 HRS, VALID AT: 160000Z --- 21.1S 170.2W MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 180 NM NORTHEAST QUADRANT 160 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 130 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 140 DEG/ 16 KTS --- 24 HRS, VALID AT: 161200Z --- 23.5S 167.9W MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING EXTRATROPICAL RADIUS OF 050 KT WINDS - 070 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 190 NM NORTHEAST QUADRANT 170 NM SOUTHEAST QUADRANT 120 NM SOUTHWEST QUADRANT 140 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 155 DEG/ 22 KTS --- 36 HRS, VALID AT: 170000Z --- 27.5S 165.9W MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY EXTRATROPICAL RADIUS OF 034 KT WINDS - 210 NM NORTHEAST QUADRANT 180 NM SOUTHEAST QUADRANT 130 NM SOUTHWEST QUADRANT 130 NM NORTHWEST QUADRANT --- REMARKS: 151500Z POSITION NEAR 20.0S 171.9W. 15DEC20. TROPICAL CYCLONE 05P (YASA), LOCATED APPROXIMATELY 359 NM WEST-NORTHWEST OF SUVA, FIJI, HAS TRACKED EASTWARD AT 05 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS AN INTENSIFYING SYSTEM, WITH A WELL-DEFINED 14NM EYE AND SPIRAL BANDS OF DEEP CONVECTION NEARLY SURROUNDING THE CORE. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE 14NM EYE IN THE EIR LOOP AND EXTRAPOLATION OF A TIGHT LLCC EVIDENT IN A 151037Z ASCAT-B BULLSEYE PASS. THE INITIAL INTENSITY IS ASSESSED WITH FAIR CONFIDENCE AT 110 KNOTS, HEDGED SLIGHTLY LOWER THAN THE PGTW AND ABRF DVORAK INTENSITY ESTIMATE OF T6.0 (115 KTS), BASED ON SLIGHTLY LOWER ESTIMATES FROM THE ADVANCED DVORAK TECHNIQUE (T5.8, 110 KNOTS) AND CIMSS SATELLITE CONSENSUS (100 KNOTS). TC YASA IS TRACKING SLOWLY EASTWARD ALONG THE SOUTHERN PERIPHERY OF AN EAST– WEST ORIENTED NEAR EQUATORIAL RIDGE (NER) POSITIONED TO THE NORTH, THROUGH A FAVORABLE ENVIRONMENT CHARACTERIZED BY WARM (28-29 DEG C) SEA SURFACE TEMPERATURES (SST), LOW (5-10 KTS) VERTICAL WIND SHEAR (VWS) AND ROBUST RADIAL OUTFLOW PROVIDED BY AN UPPER-LEVEL POINT SOURCE OVER TOP OF THE SYSTEM. TC 05P IS FORECAST TO CONTINUING TRACKING EASTWARD THROUGH TAU 24, THEN TURN SOUTHEASTWARD AS THE NER SHIFTS ORIENTATION AND MERGES WITH THE STR TO THE SOUTHEAST, FORMING A LARGE, NORTHWEST TO SOUTHEAST ORIENTED RIDGE COMPLEX. THE SYSTEM IS FORECAST TO PASS BETWEEN THE ISLANDS OF VITI LEVU AND VANUA LEVU NEAR TAU 48, THEN CONTINUE TRACKING SOUTHEAST THROUGH TAU 72. AFTER THIS POINT, TC 05P WILL TURN SOUTHWARD, THEN SOUTHWESTWARD ALONG THE NORTHERN PERIPHERY OF A STRONG RIDGE TO THE NORTH OF NEW ZEALAND. THE SYSTEM IS FORECAST TO STEADILY INTENSIFY, REACHING A PEAK OF 120 KNOTS BY TAU 24 UNDER FAVORABLE ENVIRONMENTAL CONDITIONS OF WARM (29 DEG C) SSTS, LOW VWS AND RADIAL OUTFLOW, ACCENTUATED BY A PERIOD OF IMPROVED POLEWARD OUTFLOW AS THE SYSTEM TAPS INTO THE BASE OF A PASSING MID AND UPPER-LEVEL TROUGH TO THE SOUTH. AFTER PASSING BETWEEN THE FIJIAN ISLANDS, DISRUPTION OF THE LOW-LEVEL FLOW, INCREASING VWS AND DECREASING SSTS WILL COMBINE TO WEAKEN THE SYSTEM TO 60 KNOTS BY TAU 120, AS IT BEGINS TO TRANSITION TO A SUBTROPICAL SYSTEM. NUMERICAL GUIDANCE IS IN POOR AGREEMENT. WHILE ALL MODELS AGREE ON THE OVERALL SCENARIO, THERE IS SIGNIFICANT CROSS-TRACK SPREAD WHICH STEADILY INCREASES TO 150NM AT TAU 48 AND 265NM AT TAU 120, IN ADDITION TO LARGE ALONG-TRACK SPREAD IN THE LATER TAUS. THE GFS AND NAVGEM SOLUTIONS LIE ON THE WESTERN EDGE OF THE GUIDANCE ENVELOPE AND SHOW THE SYSTEM MAKING A DIRECT HIT ON VITI LEVU NEAR TAU 48. MEANWHILE, THE UKMET ENSEMBLE LIES ALONG THE EASTERN EDGE OF THE ENVELOPE AND SHOWS THE SYSTEM TRACKING NORTH OF VANUA LEVU. THE JTWC FORECAST TRACK LIES CLOSE TO THE MULTI-MODEL CONSENSUS THROUGH TAU 48, THEN JUST TO THE EAST AND SLIGHTLY SLOWER THAN THE CONSENSUS THROUGH THE REMAINDER OF THE FORECAST. HOWEVER, IN LIGHT OF THE HIGH UNCERTAINTY IN THE TRACK GUIDANCE, THERE IS OVERALL LOW CONFIDENCE IN THE FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 151200Z IS 20 FEET. NEXT WARNINGS AT 152100Z, 160300Z, 160900Z AND 161500Z. REFER TO TROPICAL CYCLONE 05P (YASA) WARNINGS (WTPS31 PGTW) FOR SIX-HOURLY UPDATES.// NNNN