WTPS31 PGTW 312100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 15P (ANA) WARNING NR 008// RMKS/ 1. TROPICAL CYCLONE 15P (ANA) WARNING NR 008 03 ACTIVE TROPICAL CYCLONES IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 311800Z --- NEAR 20.5S 179.0E MOVEMENT PAST SIX HOURS - 155 DEGREES AT 10 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 055 NM NORTHEAST QUADRANT 055 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT 145 NM SOUTHEAST QUADRANT 115 NM SOUTHWEST QUADRANT 150 NM NORTHWEST QUADRANT REPEAT POSIT: 20.5S 179.0E --- FORECASTS: 12 HRS, VALID AT: 010600Z --- 22.0S 179.9E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 055 NM NORTHEAST QUADRANT 055 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT 135 NM SOUTHEAST QUADRANT 155 NM SOUTHWEST QUADRANT 160 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 145 DEG/ 09 KTS --- 24 HRS, VALID AT: 011800Z --- 23.4S 179.0W MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT 135 NM SOUTHEAST QUADRANT 155 NM SOUTHWEST QUADRANT 160 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 140 DEG/ 13 KTS --- 36 HRS, VALID AT: 020600Z --- 25.3S 177.2W MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 190 NM NORTHEAST QUADRANT 150 NM SOUTHEAST QUADRANT 130 NM SOUTHWEST QUADRANT 110 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 135 DEG/ 15 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 021800Z --- 27.4S 174.8W 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 - 170 NM NORTHEAST QUADRANT 150 NM SOUTHEAST QUADRANT 110 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 130 DEG/ 15 KTS --- 72 HRS, VALID AT: 031800Z --- 31.2S 169.7W MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 312100Z POSITION NEAR 20.9S 179.2E. 31JAN21. TROPICAL CYCLONE 15P (ANA), LOCATED APPROXIMATELY 148 NM SOUTH-SOUTHEAST OF SUVA, FIJI, HAS TRACKED SOUTH-SOUTHEASTWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) AND EARLY MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A BROAD AREA OF SYMMETRIC DEEP CONVECTION WITH A SHARP WESTERN EDGE AND DIFFUSE EASTERN EDGE, INDICATIVE OF STRONG WESTERLY VWS. WHILE THE EXACT CENTER OF THE LOW LEVEL CIRCULATION CENTER (LLCC) IS OBSCURED BY THE CIRRUS CANOPY AND DEEP CONVECTOIN, THERE ARE A FEW LOW LEVEL BANDS EVIDENT ON THE NORTHWEST SIDE OF THE CIRCULATION. THIS, COMBINED WITH A 311615Z SSMIS 37GHZ MICROWAVE IMAGE SHOWING A FAIRLY BROAD MICROWAVE EYE FEATURE, LENT HIGH CONFIDENCE TO THE INITIAL POSITION. THE INITIAL INTENSITY IS HELD AT 55 KNOTS WITH MODERATE CONFIDENCE BASED ON AN AVERAGE OF MULTI-AGENCY DVORAK INTENSITY ESTIMATES BETWEEN T3.5-T4.5 (55-75 KTS), AN ADT ESTIMATE OF T3.3 AND A SATCON ESTIMATE OF 60 KTS. ANALYSIS REVEALS AN OVERALL MARGINAL ENVIRONMENT CHARACTERIZED BY WARM (26-27C) SSTS AND MODERATE TO HIGH (20-25 KTS) VWS BEING OFFSET BY ROBUST POLEWARD AND MODERATE EQUATORWARD OUTFLOW. AS DEPICTED IN THE SATELLITE IMAGERY, WESTERLY VWS IS BEGINNING TO HAVE AN IMPACT ON THE OVERALL STRUCTURE OF THE SYSTEM, WITH THE LLCC STARTING TO APPEAR TO THE NORTHWEST OF THE CONVECTIVE MASS. TC 15P IS FORECAST TO CONTINUE ACCELERATING TO THE SOUTHEAST THROUGH THE FORECAST PERIOD, ALONG THE WESTERN PERIPHERY OF A DEEP STR CENTERED TO THE EAST. SLOW BUT STEADY WEAKENING IS EXPECTED THOUGH THE DURATION OF THE FORECAST AS THE SYSTEM IS IMPACTED BY INCREASING VWS AND MOVES OVER PROGRESSIVELY COOLER WATERS. AROUND TAU 48, TC 16P WILL APPROACH FROM THE NORTHEAST AND MERGE WITH TC 15P, DISRUPTING THE CORE CIRCULATION AND LEADING TO ADDITIONAL WEAKENING AS IT CROSSES THE 26C ISOTHERM, ULTIMATELY DISSIPATING BY TAU 72. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT IN THE CROSS- TRACK SOLUTIONS, WITH MODERATE AGREEMENT IN THE ALONG-TRACK SOLUTIONS. THE JTWC FORECAST LIES TO THE EAST AND SLIGHTLY FASTER THAN THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE, THOUGH THERE REMAINS SOME UNCERTAINTY DUE TO THE IMPACT OF THE BINARY INTERACTION AND MERGER OF TC 16P. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 311800Z IS 20 FEET. NEXT WARNINGS AT 010300Z, 010900Z, 011500Z AND 012100Z. REFER TO TROPICAL CYCLONE 16P (BINA) WARNINGS (WTPS32 PGTW) FOR SIX- HOURLY UPDATES. REFER TO TROPICAL CYCLONE 17P (LUCAS) WARNINGS (WTPS33 PGTW) FOR SIX-HOURLY UPDATES.// NNNN