WTPS31 PGTW 010900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 15P (ANA) WARNING NR 010// RMKS/ 1. TROPICAL CYCLONE 15P (ANA) WARNING NR 010 03 ACTIVE TROPICAL CYCLONES IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 010600Z --- NEAR 21.9S 179.5E MOVEMENT PAST SIX HOURS - 150 DEGREES AT 09 KTS POSITION ACCURATE TO WITHIN 040 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 - 065 NM NORTHEAST QUADRANT 065 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 175 NM NORTHEAST QUADRANT 145 NM SOUTHEAST QUADRANT 125 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT REPEAT POSIT: 21.9S 179.5E --- FORECASTS: 12 HRS, VALID AT: 011800Z --- 23.3S 179.2W MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 210 NM NORTHEAST QUADRANT 170 NM SOUTHEAST QUADRANT 150 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 140 DEG/ 12 KTS --- 24 HRS, VALID AT: 020600Z --- 25.1S 177.4W MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 034 KT WINDS - 180 NM NORTHEAST QUADRANT 160 NM SOUTHEAST QUADRANT 140 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 140 DEG/ 15 KTS --- 36 HRS, VALID AT: 021800Z --- 27.3S 175.2W MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 010900Z POSITION NEAR 22.2S 179.8E. 01FEB21. TROPICAL CYCLONE (TC) 15P (ANA), LOCATED APPROXIMATELY 236 NM SOUTH-SOUTHEAST OF SUVA, FIJI, HAS TRACKED SOUTH-SOUTHEASTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS AN EXPOSED, BROAD LOW-LEVEL CIRCULATION CENTER (LLCC) WITH DEEP CONVECTION SHEARED TO THE SOUTHEAST AND A LARGE REGION OF STRATOCUMULUS (COOLER, DRIER, MORE STABLE AIR) ADVECTING OVER THE WESTERN SEMICIRCLE. A 010425Z SSMIS 37GHZ MICROWAVE IMAGE REVEALS SHALLOW BANDING WRAPPING AROUND THE EASTERN AND SOUTHERN SEMICIRCLES OF A DEFINED LLCC, WHICH SUPPORTS THE INITIAL POSITION WITH GOOD CONFIDENCE. THE INITIAL INTENSITY IS ASSESSED AT 50 KNOTS BASED ON A PGTW DVORAK ESTIMATE OF T3.0/3.5 (45/55 KNOTS). UPPER- LEVEL ANALYSIS INDICATES A MARGINAL ENVIRONMENT WITH STRONG (30-35 KNOTS) VERTICAL WIND SHEAR, ASSOCIATED WITH SUBTROPICAL WESTERLY FLOW ALOFT, OFFSET BY ROBUST POLEWARD OUTFLOW. TC 15P IS FORECAST TO ACCELERATE SOUTHEASTWARD THROUGH TAU 36 ALONG THE SOUTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE WITH INCREASING VWS (35-40 KNOTS). ADDITIONALLY, SST VALUES ARE EXPECTED TO DECREASE TO 26-25C AFTER TAU 12, WHICH WILL LEAD TO MORE RAPID WEAKENING AND DISSIPATION BY TAU 36. NUMERICAL MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT LENDING HIGH CONFIDENCE TO THE JTWC FORECAST TRACK WITH A 45NM SPREAD IN MODEL SOLUTIONS AT TAU 36. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 010600Z IS 21 FEET. NEXT WARNINGS AT 011500Z, 012100Z, 020300Z AND 020900Z. REFER TO TROPICAL CYCLONE 16P (BINA) FINAL WARNING (WTPS32 PGTW). REFER TO TROPICAL CYCLONE 17P (LUCAS) WARNINGS (WTPS33 PGTW) FOR SIX-HOURLY UPDATES.// NNNN