WTPS31 PGTW 310300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 15P (ANA) WARNING NR 005// RMKS/ 1. TROPICAL CYCLONE 15P (ANA) WARNING NR 005 03 ACTIVE TROPICAL CYCLONES IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 310000Z --- NEAR 18.2S 178.6E MOVEMENT PAST SIX HOURS - 150 DEGREES AT 08 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 090 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 025 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 165 NM NORTHEAST QUADRANT 120 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 180 NM NORTHWEST QUADRANT REPEAT POSIT: 18.2S 178.6E --- FORECASTS: 12 HRS, VALID AT: 311200Z --- 19.7S 179.0E MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 010 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 200 NM NORTHEAST QUADRANT 140 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 140 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 170 DEG/ 07 KTS --- 24 HRS, VALID AT: 010000Z --- 21.0S 179.2E MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 230 NM NORTHEAST QUADRANT 160 NM SOUTHEAST QUADRANT 130 NM SOUTHWEST QUADRANT 110 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 145 DEG/ 06 KTS --- 36 HRS, VALID AT: 011200Z --- 22.0S 179.9E 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 030 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 220 NM NORTHEAST QUADRANT 160 NM SOUTHEAST QUADRANT 140 NM SOUTHWEST QUADRANT 110 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 150 DEG/ 09 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 020000Z --- 23.5S 179.1W MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 090 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 190 NM NORTHEAST QUADRANT 150 NM SOUTHEAST QUADRANT 130 NM SOUTHWEST QUADRANT 110 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 140 DEG/ 11 KTS --- 72 HRS, VALID AT: 030000Z --- 26.8S 176.2W 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 - 140 NM NORTHEAST QUADRANT 120 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 140 DEG/ 13 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 040000Z --- 30.8S 172.3W MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 310300Z POSITION NEAR 18.6S 178.7E. 31JAN21. TROPICAL CYCLONE 15P (ANA), LOCATED APPROXIMATELY 13 NM EAST-SOUTHEAST OF SUVA, FIJI, HAS TRACKED SOUTH-SOUTHEASTWARD AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) INDICATES A WELL ORGANIZED, SYMMETRIC CENTRAL DENSE OVERCAST OBSCURING THE LOW LEVEL CIRCULATION CENTER (LLCC) AND OVERSHOOTING TOPS NEAR THE CENTER. A 302235Z GMI 89GHZ MICROWAVE IMAGE DEPICTED A WEAK CENTER OVER SOUTHERN VITI LEVU WITH WELL DEFINED CONVECTIVE BANDS TO THE SOUTH AND WRAPPING INTO THE LLCC, LENDING HIGH CONFIDENCE TO THE INITIAL POSITION. THE INITIAL INTENSITY IS ASSESSED WITH MODERATE CONFIDENCE BASED ON A DVORAK CURRENT INTENSITY ESTIMATE OF T4.0 (65 KTS) FROM PGTW (AUTOMATED FIXES WERE OVERLAND AND THUS PROVIDED NO INTENSITY ESTIMATE). UPPER- LEVEL ANALYSIS REVEALS THE SYSTEM LIES IN A REGION WHICH IS CURRENTLY FAVORABLE WITH LOW (10-15 KTS) VWS, STRONG POLEWARD AND MODERATE EQUATORWARD OUTFLOW AND WARM (27-28C) WATERS. TC 15P IS CURRENTLY TRACKING SOUTHWARD ALONG THE WESTERN PERIPHERY OF A DEEP- LAYER SUBTROPICAL RIDGE (STR) CENTERED TO THE EAST. THE SYSTEM IS FORECAST TO SOUTH-SOUTHEASTWARD THROUGH THE DURATION OF THE FORECAST PERIOD ALONG THE WESTERN SIDE OF THE AFOREMENTIONED STR. TC 15P HAS LIKELY REACHED THE PEAK OF ITS INTENSITY BUT IS FORECAST TO MAINTAIN 65 KNOTS THROUGH TAU 12. THE SYSTEM WILL SLOWLY WEAKEN THROUGH TAU 48 PRIMARILY DUE TO SLOWLY INCREASING VWS. AFTER TAU 48, THE SYSTEM WILL BEGIN TO INTERACT WITH THE MORE SUBSTANTIAL MID-LATITUDE WESTERLIES AHEAD OF AN APPROACHING TROUGH, LEADING TO DRAMATICALLY INCREASED VWS VALUES, WHILE ALSO MOVING OVER INCREASINGLY COOLER WATERS, LEADING TO A MUCH FASTER RATE OF WEAKENING. ADDITIONALLY, TC 16P IS EXPECTED TO RAPIDLY APPROACH FROM THE NORTH AND ULTIMATELY BE ABSORBED WITHIN TC 15P WHICH WILL CAUSE THE SYSTEM TO WEAKEN EVEN FURTHER AS THE CORE IS DISRUPTED BY THE MERGER WITH TC 16P. TC 15P IS FORECAST TO FULLY DISSIPATE AS A TROPICAL CYCLONE BY TAU 96. NUMERICAL MODEL GUIDANCE IS IN GOOD OVERALL AGREEMENT ON THE TRACK SCENARIO BUT WITH SIGNIFICANT ALONG-TRACK SPREAD, PARTICULARLY IN THE LATER TAUS. THE JTWC FORECAST TRACK REMAINS CONSISTENT WITH THE PREVIOUS FORECAST AND LIES NEAR TO BUT SLOWER OVERALL, THAN THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE THROUGH TAU 48, AND LOW CONFIDENCE THEREAFTER. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 310000Z IS 20 FEET. NEXT WARNINGS AT 310900Z, 311500Z, 312100Z AND 010300Z. REFER TO TROPICAL CYCLONE 16P (SIXTEEN) WARNINGS (WTPS32 PGTW) FOR SIX-HOURLY UPDATES. REFER TO TROPICAL CYCLONE 17P (SEVENTEEN) WARNINGS (WTPS33 PGTW) FOR SIX-HOURLY UPDATES.// NNNN