WTPS31 PGTW 100300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 20P (TWENTY) WARNING NR 001// REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/091451ZFEB2021// AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.// RMKS/ 1. TROPICAL CYCLONE 20P (TWENTY) WARNING NR 001 01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 100000Z --- NEAR 25.1S 177.7W MOVEMENT PAST SIX HOURS - 175 DEGREES AT 16 KTS POSITION ACCURATE TO WITHIN 050 NM POSITION BASED ON CENTER LOCATED BY A COMBINATION OF SATELLITE AND EXTRAPOLATION PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT REPEAT POSIT: 25.1S 177.7W --- FORECASTS: 12 HRS, VALID AT: 101200Z --- 28.7S 176.9W MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 000 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 190 NM NORTHEAST QUADRANT 160 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 165 DEG/ 18 KTS --- 24 HRS, VALID AT: 110000Z --- 32.2S 175.6W MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING EXTRATROPICAL RADIUS OF 034 KT WINDS - 160 NM NORTHEAST QUADRANT 140 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 150 DEG/ 17 KTS --- 36 HRS, VALID AT: 111200Z --- 35.2S 173.5W MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING EXTRATROPICAL RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 010 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 140 DEG/ 20 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 120000Z --- 38.2S 170.3W MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT WIND RADII VALID OVER OPEN WATER ONLY EXTRATROPICAL --- REMARKS: 100300Z POSITION NEAR 26.0S 177.5W. 10FEB21. TROPICAL CYCLONE (TC) 20P (TWENTY), LOCATED APPROXIMATELY 473 NM SOUTH-SOUTHEAST OF SUVA, FIJI, HAS TRACKED SOUTHWARD AT 16 KNOTS (KTS) OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS CONVECTIVE BANDING WRAPPING INTO A PARTIALLY EXPOSED LOW LEVEL CIRCULATION WITH THE ASSOCIATED DEEP CONVECTION BEING SHEARED OVER THE EASTERN SEMICIRCLE. AN EXTRAPOLATION OF A 092048Z BULLSEYE METOP-B ASCAT IMAGE IN CONJUNCTION WITH THE MSI LENDS GOOD CONFIDENCE TO THE INITIAL POSITION. THE INITIAL INTENSITY OF 45 KTS IS HEDGED BETWEEN MULTI- AGENCY DVORAK CURRENT INTENSITY ESTIMATES OF T2.5-3.5 (35-55 KTS, KNES/PGTW/ABRF) AND IS BASED ON A SWATH OF 40-45KT WIND BARBS IN THE AFOREMENTIONED ASCAT IMAGE. THE 34-KNOT WIND RADII HAVE BEEN UPDATED BASED ON THE ASCAT PASS AS WELL. ENVIRONMENTAL ANALYSIS REVEALS TC 20P IS TRACKING INTO A MARGINALLY FAVORABLE ENVIRONMENT CHARACTERIZED BY WARM (26-27 CELSIUS) SEA SURFACE TEMPERATURES (SST) AND ROBUST DUAL CHANNEL UPPER LEVEL OUTFLOW OFFSET BY PERSISTENT HIGH (25-30 KTS) VERTICAL WIND SHEAR (VWS). TC 20P IS TRACKING ALONG THE WESTERN PERIPHERY OF AN EXTENSION OF A NEAR EQUATORIAL RIDGE (NER) POSITIONED TO THE NORTHEAST. THE NER IS EXPECTED TO STEER THE SYSTEM GENERALLY SOUTH-SOUTHEASTWARD FOR THE DURATION OF THE FORECAST. IN THE NEAR TERM, THE CONDUCIVE SST AND ROBUST OUTFLOW ALOFT WILL ALLOW THE SYSTEM A BRIEF PERIOD OF INTENSIFICATION TO 50 KTS BY TAU 12. AFTERWARDS, THE SYSTEM WILL STEADILY WEAKEN DUE TO CONTINUED HIGH VWS AND RAPIDLY COOLING SST (20-21 CELSIUS BY TAU 48). BY TAU 24, THE SYSTEM WILL BEGIN TO INTERACT WITH THE BAROCLINIC ZONE AND START EXTRATROPICAL TRANSITION (ETT). NUMERICAL MODEL GUIDANCE IS IN STRONG AGREEMENT WITH A SPREAD OF 80 NM AT TAU 36. AFTER TAU 36, THE MODEL SOLUTIONS BEGIN TO DIVERGE AS THE SYSTEM BECOMES EMBEDDED WITHIN THE WESTERLY FLOW AND COMPLETES ETT BY TAU 48, IF NOT SOONER. OVERALL, THERE IS GOOD CONFIDENCE IN THE JTWC TRACK FORECAST WHICH LIES NEAR THE MULTI-MODEL CONSENSUS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 100000Z IS 18 FEET. NEXT WARNINGS AT 100900Z, 101500Z, 102100Z AND 110300Z. 2. THIS CANCELS AND SUPERCEDES REF A (WTPS21 PGTW 091500 COR).// NNNN