WTPS31 PGTW 171500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 05P (YASA) WARNING NR 021// RMKS/ 1. TROPICAL CYCLONE 05P (YASA) WARNING NR 021 01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 171200Z --- NEAR 17.2S 179.9W MOVEMENT PAST SIX HOURS - 120 DEGREES AT 14 KTS POSITION ACCURATE TO WITHIN 050 NM POSITION BASED ON CENTER LOCATED BY A COMBINATION OF SATELLITE AND RADAR PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 115 KT, GUSTS 140 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 055 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 045 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 100 NM NORTHEAST QUADRANT 095 NM SOUTHEAST QUADRANT 085 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 175 NM NORTHEAST QUADRANT 170 NM SOUTHEAST QUADRANT 155 NM SOUTHWEST QUADRANT 145 NM NORTHWEST QUADRANT REPEAT POSIT: 17.2S 179.9W --- FORECASTS: 12 HRS, VALID AT: 180000Z --- 18.4S 178.3W MAX SUSTAINED WINDS - 105 KT, GUSTS 130 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 030 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 070 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 160 NM NORTHEAST QUADRANT 170 NM SOUTHEAST QUADRANT 140 NM SOUTHWEST QUADRANT 130 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 150 DEG/ 09 KTS --- 24 HRS, VALID AT: 181200Z --- 19.9S 177.3W MAX SUSTAINED WINDS - 095 KT, GUSTS 115 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT 160 NM SOUTHEAST QUADRANT 140 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 160 DEG/ 07 KTS --- 36 HRS, VALID AT: 190000Z --- 21.2S 176.8W MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 010 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 130 NM NORTHEAST QUADRANT 150 NM SOUTHEAST QUADRANT 130 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 190 DEG/ 06 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 191200Z --- 22.4S 177.0W MAX SUSTAINED WINDS - 070 KT, GUSTS 085 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 010 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT 140 NM SOUTHEAST QUADRANT 130 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 215 DEG/ 04 KTS --- 72 HRS, VALID AT: 201200Z --- 23.7S 178.0W MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING SUBTROPICAL RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT 140 NM SOUTHEAST QUADRANT 120 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 235 DEG/ 06 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 211200Z --- 25.1S 179.7E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY SUBTROPICAL RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT 140 NM SOUTHEAST QUADRANT 120 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 120 HR POSIT: 250 DEG/ 06 KTS --- 120 HRS, VALID AT: 221200Z --- 25.9S 177.2E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY SUBTROPICAL RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT 140 NM SOUTHEAST QUADRANT 120 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT --- REMARKS: 171500Z POSITION NEAR 17.5S 179.5W. 17DEC20. TROPICAL CYCLONE 05P (YASA), LOCATED APPROXIMATELY 111 NM EAST-NORTHEAST OF SUVA, FIJI, HAS TRACKED EAST-SOUTHEASTWARD AT 14 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A DRAMATICALLY WEAKENED SYSTEM, WITH THE PREVIOUSLY WELL ESTABLISHED EYE HAVING FULLY FILLED IN AND DISSIPATED BY THE 0600Z HOUR, AFTER PASSING OVER THE ISLAND OF VANUA LEVU. THE INITIAL POSITION IS PLACED WITH MODERATE CONFIDENCE DUE TO THE OBSCURED NATURE OF THE LOW-LEVEL CIRCULATION CENTER (LLCC) AND THE LACK OF ANY RECENT MICROWAVE IMAGERY. FIJI RADAR DATA WAS NOT CONCLUSIVE, BUT DID PROVIDE SOME ADDITIONAL CLARITY TO THE INITIAL POSITION. THE INITIAL INTENSITY IS ASSESSED AT 115 KNOTS BASED ON A PGTW/KNES DVORAK CURRENT INTENSITY ESTIMATES OF T6.0 (115 KTS), AND AN ADVANCED DVORAK TECHNIQUE (ADT) ESTIMATE OF T5.5 (102 KTS). UPPER- LEVEL ANALYSIS INDICATES RADIAL OUTFLOW WITH ENHANCED, BUT WEAKENING, POLEWARD OUTFLOW INTO THE MID-LATITUDE WESTERLIES TO THE SOUTH, WITH MODERATE (15-25 KTS) VWS. SEA SURFACE TEMPERATURES REMAIN WARM (27-28C). TC 05P IS FORECAST TO CONTINUE TRACKING SOUTHEASTWARD THROUGH TAU 24 UNDER THE STEERING INFLUENCE OF THE DEEP-LAYER NEAR EQUATORIAL-SUBTROPICAL RIDGE (NER-STR) COMPLEX LOCATED TO THE EAST. AFTER TAU 24, A RELATIVELY STRONG MID-LATITUDE TROUGH WILL PASS BY TO THE SOUTH, WEAKENING THE STEERING RIDGE TO THE EAST, ALLOWING FOR THE SYSTEM TO SLOW DOWN AND TURN SOUTH THROUGH TAU 48. THEREAFTER ANOTHER STR DEVELOPS AND BUILDS NORTH OF THE NEW ZEALAND, BECOMING THE DOMINATE STEERING MECHANISM AND PUSHING TC 05P ONTO A SOUTHWESTWARD TRACK BY TAU 72. THE COMBINATION OF STEADILY INCREASING VWS AND DECREASING SSTS WILL OFFSET THE CONTINUED ROBUST OUTFLOW, LEADING TO STEADY WEAKENING THROUGH TAU 96. AROUND TAU 72, AS THE SYSTEM MOVES OVER WATERS COOLER THAN 26C AND BEGINS TO INTERACT WITH AN UPPER-LEVEL 200MB LOW, IT IS FORECAST TO TRANSITION TO A SUBTROPICAL STORM, COMPLETING THE TRANSITION BY TAU 96. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT THROUGH TAU 48 AND THIS PORTION OF THE JTWC FORECAST IS LAID NEAR THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE. IN THE TAU 72-120 RANGE HOWEVER, THERE IS HIGH UNCERTAINTY IN THE TIMING AND STRENGTH OF THE TURN TO THE SOUTHWEST, WITH GFS BEING THE SHARPEST AND FASTEST TURN, WHILE THE ECMWF IS THE SLOWEST AND TURNS THE SYSTEM TOWARDS THE EAST, LEADING TO A NEARLY 600NM SPREAD BY TAU 120. THIS PORTION OF THE JTWC FORECAST TRACK LIES FAIRLY CLOSE THE GFS SOLUTION, TO THE WEST AND SLIGHTLY SLOWER THAN THE CONSENSUS TRACK WITH LOW CONFIDENCE DUE TO THE HIGH UNCERTAINTY IN THE TRACK GUIDANCE.MAXIMUM SIGNIFICANT WAVE HEIGHT AT 171200Z IS 30 FEET. NEXT WARNINGS AT 172100Z, 180300Z, 180900Z AND 181500Z.// NNNN