WTPS31 PGTW 220100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 20P (REUBEN) WARNING NR 002// RMKS/ 1. TROPICAL CYCLONE 20P (REUBEN) WARNING NR 002 02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 220000Z --- NEAR 23.4S 174.9W MOVEMENT PAST SIX HOURS - 130 DEGREES AT 13 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT 075 NM SOUTHEAST QUADRANT 075 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT REPEAT POSIT: 23.4S 174.9W --- FORECASTS: 12 HRS, VALID AT: 221200Z --- 24.6S 174.1W MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 075 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 170 DEG/ 06 KTS --- 24 HRS, VALID AT: 230000Z --- 25.7S 173.9W MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 075 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 195 DEG/ 03 KTS --- 36 HRS, VALID AT: 231200Z --- 26.3S 174.1W MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT 075 NM SOUTHEAST QUADRANT 075 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 235 DEG/ 03 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 240000Z --- 26.7S 174.7W MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER VECTOR TO 72 HR POSIT: 215 DEG/ 03 KTS --- 72 HRS, VALID AT: 250000Z --- 27.7S 175.5W MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 220300Z POSITION NEAR 23.7S 174.7W. TROPICAL CYCLONE (TC) 20P (REUBEN), LOCATED APPROXIMATELY 492 NM SOUTHEAST OF SUVA, FIJI, HAS TRACKED SOUTHEASTWARD AT 13 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) CONTINUES TO DEPICT PERSISTENT DEEP CONVECTION SHEARED TO THE SOUTHEAST. AN OLDER 202114Z ASCAT PASS PARTIALLY SHOWED 35 TO 40 KNOT WINDS ON THE EASTERN SEMI-CIRCLE. THE CURRENT POSITION IS BASED ON THE MSI AND SATELLITE FIXES FROM PGTW, KNES AND PHFO WITH GOOD CONFIDENCE. THE INITIAL INTENSITY OF 40 KNOTS IS BASED ON THE ASCAT DATA AND HEDGED HIGHER THAN CONSENSUS DVORAK ESTIMATES OF T2.5 FROM ALL REPORTING AGENCIES. UPPER LEVEL ANALYSIS INDICATES TC REUBEN REMAINS IN AN AREA OF MODERATE (20-25 KNOT) VERTICAL WIND SHEAR (VWS) OFFSET BY EXCELLENT POLEWARD OUTFLOW, AS EVIDENT ON THE WATER VAPOR IMAGERY. TC 20P IS CURRENTLY TRACKING ALONG THE WESTERN PERIPHERY OF A MID-LAYERED SUBTROPICAL RIDGE (STR) TO THE EAST. AFTER TAU 24, TC REUBEN IS EXPECTED TO SLOW DOWN AS A MIGRATORY UPPER-LEVEL TROUGH PASSES TO THE NORTH WEAKENING THE STR. MARGINALLY- FAVORABLE CONDITIONS WILL REMAIN ALLOWING THE SYSTEM TO SLIGHTLY INTENSIFY OVER THE NEXT 24 HOURS. AFTERWARDS, THE COMBINED EFFECT OF INCREASING VWS AND COOLING SEA SURFACE TEMPERATURES WILL ERODE THE CYCLONE LEADING TO ITS DISSIPATION BY THE END OF THE FORECAST PERIOD. DUE TO A LARGE SPREAD AMONG AVAILABLE MODEL GUIDANCE, JTWC TRACK FORECAST CONFIDENCE LEVEL REMAINS LOW. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 220000Z IS 14 FEET. NEXT WARNINGS AT 221500Z AND 230300Z. REFER TO TROPICAL CYCLONE 18P (NATHAN) WARNINGS (WTPS32 PGTW) FOR TWELVE-HOURLY UPDATES.//