WTPS31 PGTW 172100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 05P (YASA) WARNING NR 022// RMKS/ 1. TROPICAL CYCLONE 05P (YASA) WARNING NR 022 01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 171800Z --- NEAR 17.9S 179.4W MOVEMENT PAST SIX HOURS - 135 DEGREES AT 12 KTS POSITION ACCURATE TO WITHIN 020 NM POSITION BASED ON CENTER LOCATED BY A COMBINATION OF SATELLITE AND SYNOPTIC DATA PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 060 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 110 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 085 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 190 NM NORTHEAST QUADRANT 165 NM SOUTHEAST QUADRANT 150 NM SOUTHWEST QUADRANT 175 NM NORTHWEST QUADRANT REPEAT POSIT: 17.9S 179.4W --- FORECASTS: 12 HRS, VALID AT: 180600Z --- 19.4S 177.9W MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 030 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 080 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 180 NM NORTHEAST QUADRANT 170 NM SOUTHEAST QUADRANT 120 NM SOUTHWEST QUADRANT 130 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 150 DEG/ 08 KTS --- 24 HRS, VALID AT: 181800Z --- 20.7S 177.1W MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 030 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT 150 NM SOUTHEAST QUADRANT 120 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 170 DEG/ 07 KTS --- 36 HRS, VALID AT: 190600Z --- 22.0S 176.9W MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING SUBTROPICAL RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT 130 NM SOUTHEAST QUADRANT 110 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 195 DEG/ 05 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 191800Z --- 23.0S 177.2W MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING SUBTROPICAL RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT 110 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 220 DEG/ 05 KTS --- 72 HRS, VALID AT: 201800Z --- 24.4S 178.5W MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY SUBTROPICAL RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT 120 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT --- REMARKS: 172100Z POSITION NEAR 18.3S 179.0W. 17DEC20. TROPICAL CYCLONE (TC) 05P (YASA), LOCATED APPROXIMATELY 126 NM EAST OF SUVA, FIJI, HAS TRACKED SOUTHEASTWARD AT 12 KNOTS OVER THE PAST SIX HOURS. AFTER COMPLETING AN EYEWALL REPLACEMENT CYCLE WHILE CROSSING VANUA LEVU, TC 05P HAS BEGUN TO INTERACT WITH AN APPROACHING UPPER-LEVEL TROUGH WITH INCREASING (20-25 KNOTS) VERTICAL WIND SHEAR (VWS), WHICH HAS CONTRIBUTED TO A SIGNIFICANT WEAKENING TREND. ANIMATED MULTISPECTRAL SATELLITE IMAGERY CURRENTLY DEPICTS AN EXPOSED, TIGHTLY-WRAPPED LOW-LEVEL CIRCULATION CENTER (LLCC), WHICH SUPPORTS THE INITIAL POSITION WITH GOOD CONFIDENCE, AND RAPIDLY DECAYING DEEP CONVECTION SHEARED TO THE SOUTHEAST. THUS, DVORAK DATA-T INTENSITY ESTIMATES HAVE DROPPED TO T4.5 (77 KNOTS) WITH CURRENT INTENSITY ESTIMATES AT 5.5 (102 KNOTS). THESE ESTIMATES ARE IN AGREEMENT WITH THE 171800Z ADT ESTIMATE OF T4.6/5.3 (80/100 KNOTS). THE SYSTEM'S CENTER IS CURRENTLY LOCATED 38NM WEST-NORTHWEST OF LAKEBA ISLAND, WHICH IS REPORTING NORTHEASTERLY WINDS AT 40 KNOTS (10-MINUTE AVERAGE). TC 05P WILL TRACK SOUTHEASTWARD TO SOUTHWARD ALONG THE PERIPHERY OF THE SUBTROPICAL RIDGE TO THE NORTHEAST BUT WILL REMAIN EMBEDDED WITHIN THE DEEP UPPER-LEVEL TROUGH WITH MODERATE TO STRONG VWS AND CONVERGENCE ALOFT, WHICH WILL LEAD TO A STEADY WEAKENING TREND. NUMERICAL MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT DURING THIS PHASE. AFTER TAU 36, TC 05P WILL BEGIN SUBTROPICAL TRANSITION AS IT APPROACHES THE SUBTROPICAL JET WITH VWS INCREASING TO 35 TO 50 KNOTS AND SST VALUES COOLING TO 25C. TC 05P IS FORECAST TO COMPLETE SUBTROPICAL TRANSITION AS IT TRACKS UNDER THE AFOREMENTIONED JET AND THE WIND FIELD EXPANDS AND BECOMES HIGHLY ASYMMETRIC. AFTER TAU 36, NUMERICAL MODEL GUIDANCE DIVERGES WITH INCREASING UNCERTAINTY IN THE JTWC FORECAST TRACK DUE TO THE COMPLEX TRANSITION AND MERGER WITH THE UPPER-LEVEL TROUGH / LOW. THEREFORE, THERE IS MODERATE OVERALL CONFIDENCE IN THE JTWC FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 171800Z IS 28 FEET. NEXT WARNINGS AT 180300Z, 180900Z, 181500Z AND 182100Z.// NNNN