WTPS31 PGTW 190900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 05P (YASA) WARNING NR 028// RMKS/ 1. TROPICAL CYCLONE 05P (YASA) WARNING NR 028 01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 190600Z --- NEAR 21.7S 178.0W MOVEMENT PAST SIX HOURS - 180 DEGREES AT 08 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING EXTRATROPICAL RADIUS OF 034 KT WINDS - 135 NM NORTHEAST QUADRANT 195 NM SOUTHEAST QUADRANT 160 NM SOUTHWEST QUADRANT 115 NM NORTHWEST QUADRANT REPEAT POSIT: 21.7S 178.0W --- FORECASTS: 12 HRS, VALID AT: 191800Z --- 22.7S 178.1W MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING EXTRATROPICAL RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT 140 NM SOUTHEAST QUADRANT 120 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 205 DEG/ 06 KTS --- 24 HRS, VALID AT: 200600Z --- 23.8S 178.6W MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING EXTRATROPICAL RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT 140 NM SOUTHEAST QUADRANT 120 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 210 DEG/ 06 KTS --- 36 HRS, VALID AT: 201800Z --- 24.9S 179.3W MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY EXTRATROPICAL RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT 140 NM SOUTHEAST QUADRANT 120 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT --- REMARKS: 190900Z POSITION NEAR 22.0S 178.0W. 19DEC20. TROPICAL CYCLONE 05P (YASA), LOCATED APPROXIMATELY 296 NM SOUTHEAST OF SUVA, FIJI, HAS TRACKED SOUTHWARD AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS AN ELONGATED AND RAGGED LOW-LEVEL CIRCULATION CENTER (LLCC), WITH FLARING DEEP CONVECTION TO THE SOUTHEAST AND EXPOSED OUTER BANDS TO THE WEST. THE SYSTEM IS CONTINUING TO TRACK SOUTH- SOUTHEASTWARD AS IT INTERACTS WITH AN APPROACHING UPPER-LEVEL TROUGH TO THE WEST AND CROSSES THE 26C ISOTHERM. THE INITIAL POSITION IS ASSESSED WITH FAIR CONFIDENCE BASED ON THE PARTIALLY EXPOSED LLCC IN THE VISIBLE IMAGERY AND A RAGGED LLCC EVIDENT IN A 190621Z AMSU-B COMPOSITE MICROWAVE IMAGE. THE INITIAL INTENSITY IS ASSESSED AT 45 KNOTS WITH FAIR CONFIDENCE BASED ON MULTI-AGENCY DVORAK INTENSITY ESTIMATES BETWEEN T3.0-3.5 (PGTW AND KNES), AND AN ADVANCED DVORAK TECHNIQUE (ADT) ESTIMATE OF T2.9 (44 KNOTS). TC 05P IS FORECAST TO CONTINUE TRACKING SOUTH-SOUTHWEST ALONG THE SOUTHWEST PERIPHERY OF AN EXTENSION OF THE STR WHICH IS BUILDING SOUTHWARD TO THE EAST OF THE SYSTEM. OVER THE NEXT 24 HOURS, THE SYSTEM IS FORECAST TO BECOME FULLY EMBEDDED UNDER THE UPPER-LEVEL TROUGH. VERTICAL WIND SHEAR (VWS) IS EXPECTED TO STEADILY INCREASE TO WELL OVER 50 KONTS AHEAD OF THE TROUGH, THEN DECREASE AFTER THE SYSTEM BECOMES VERTICALLY STACKED WITH THE TROUGH ALOFT. AS TC 05P MOVES SOUTH OVER COOLER (24- 25C) WATERS AND IS DECAPITATED BY THE HIGH VWS, IT WILL RAPIDLY TRANSITION TO A SHALLOW, WARM CORE, SUBTROPICAL SYSTEM BY TAU 36. SLIGHT WEAKENING IS FORECAST THROUGH THE FORECAST PERIOD, BUT WILL REMAIN A STRONG SUBTROPICAL LOW AT TAU 36. NUMERICAL MODEL GUIDANCE IS IS FAIR AGREEMENT, WITH INCREASING UNDERTAINTY AFTER TAU 24 DUE TO THE COMPLEX INTERACTION WITH THE UPPER-LEVEL TROUGH AND SUBTROPCAL TRANSITION, LENDING OVERALL FAIR CONFIDENCE TO THE JTWC FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 190600Z IS 20 FEET. NEXT WARNINGS AT 191500Z, 192100Z, 200300Z AND 200900Z.// NNNN