WTPS31 PGTW 272100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 04P (FOUR) WARNING NR 001// REF/A/JOINT TYPHOON WRNCEN PEARL HARBOR HI/261921NOV15// AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.// RMKS/ 1. TROPICAL CYCLONE 04P (FOUR) 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: 271800Z --- NEAR 13.4S 174.9W MOVEMENT PAST SIX HOURS - 125 DEGREES AT 13 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY REPEAT POSIT: 13.4S 174.9W --- FORECASTS: 12 HRS, VALID AT: 280600Z --- 14.4S 172.8W MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT 065 NM SOUTHEAST QUADRANT 065 NM SOUTHWEST QUADRANT 075 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 125 DEG/ 12 KTS --- 24 HRS, VALID AT: 281800Z --- 15.7S 170.7W MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT 075 NM SOUTHEAST QUADRANT 075 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 140 DEG/ 12 KTS --- 36 HRS, VALID AT: 290600Z --- 17.6S 169.1W MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING EXTRATROPICAL RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT 075 NM SOUTHEAST QUADRANT 075 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 145 DEG/ 11 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 291800Z --- 19.5S 167.8W MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING EXTRATROPICAL RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 140 DEG/ 06 KTS --- 72 HRS, VALID AT: 301800Z --- 21.3S 166.3W MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY EXTRATROPICAL --- REMARKS: 272100Z POSITION NEAR 13.7S 174.4W. TROPICAL CYCLONE (TC) 04P (FOUR), LOCATED APPROXIMATELY 251 NM WEST- NORTHWEST OF PAGO PAGO, HAS TRACKED SOUTHEASTWARD AT 13 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED AND VISIBLE SATELLITE IMAGERY INDICATE A CONSOLIDATING SYSTEM WITH INCREASING DEEP CONVECTION OVER THE LOW-LEVEL CIRCULATION CENTER (LLCC). A 271809Z SSMIS IMAGE DEPICTS IMPROVED DEEP CONVECTIVE BANDING OVER THE SOUTHERN SEMI-CIRCLE WRAPPING INTO THE SOUTHWEST QUADRANT OF THE LLCC WITH SHALLOW BANDING ELSEWHERE. UPPER-LEVEL ANALYSIS INDICATES LOW TO MODERATE NORTHWESTERLY VERTICAL WIND SHEAR (VWS), ASSOCIATED WITH A BROAD UPPER-LEVEL TROUGH, OFFSET BY GOOD POLEWARD OUTFLOW. SST VALUES ARE FAVORABLE AT 28 TO 29 CELSIUS. OVERALL, THERE IS FAIR CONFIDENCE IN THE CURRENT POSITION BASED ON THE SSMIS IMAGE AND LIMITED VISIBLE IMAGERY. THE INITIAL INTENSITY IS ASSESSED AT 35 KNOTS BASED ON THE HIGHER RANGE OF DVORAK INTENSITY ESTIMATES RANGING FROM T2.0 (30 KNOTS) TO T2.5 (35 KNOTS). TC 04P IS FORECAST TO TRACK EAST-SOUTHEASTWARD ALONG THE SOUTHERN PERIPHERY OF THE NEAR- EQUATORIAL RIDGE THROUGH TAU 24 BUT SHOULD GRADUALLY TURN SOUTHEASTWARD AS IT TRANSITIONS TO THE STEERING INFLUENCE OF THE SUBTROPICAL RIDGE. TC 04P IS EXPECTED TO INTENSIFY TO A PEAK OF 55 KNOTS BY TAU 24 TO 36 UNDER MARGINALLY-FAVORABLE CONDITIONS. HOWEVER, AFTER TAU 36, VWS IS FORECAST TO INCREASE MARKEDLY WITH SST VALUES DROPPING BELOW 26 CELSIUS, WHICH WILL SERVE TO WEAKEN THE SYSTEM. ADDITIONALLY, THE SYSTEM WILL BEGIN EXTRA-TROPICAL TRANSITION (ETT) AS IT INTERACTS WITH A WEAK BAROCLINIC ZONE. TC 04P WILL COMPLETE ETT BY TAU 72 AS IT GAINS FRONTAL CHARACTERISTICS AND IS EXPECTED TO REMAIN A GALE-FORCE LOW. OVERALL, THERE IS LOW CONFIDENCE IN THE JTWC FORECAST TRACK DUE TO A LARGE SPREAD IN DYNAMIC MODEL SOLUTIONS WITH SIGNIFICANT DIFFERENCES IN TRACK SPEED. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 271800Z IS 10 FEET. NEXT WARNINGS AT 280300Z, 280900Z, 281500Z AND 282100Z. THIS WARNING SUPERSEDES AND CANCELS REF A, JOINT TYPHOON WRNCEN 261921 NOV 15 TROPICAL CYCLONE FORMATION ALERT (WTPS21 PGTW 261930).//