WTPS21 PGTW 282130 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 91P) REISSUED// REF/A/JOINT TYPHOON WRNCEN PEARL HARBOR HI/272121DEC2024// AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.// RMKS/ 1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN 120 NM EITHER SIDE OF A LINE FROM 16.3S 173.8E TO 17.1S 179.7W WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME. WINDS IN THE AREA ARE ESTIMATED TO BE 28 TO 33 KNOTS. METSAT IMAGERY AT 281800Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 16.3S 174.2E. THE SYSTEM IS MOVING EAST-SOUTHEASTWARD AT 04 KNOTS. 2. REMARKS: THE AREA OF CONVECTION (INVEST 91P) PREVIOUSLY LOCATED NEAR 14.7S 170.9E IS NOW LOCATED HAS NEAR 16.3S 174.2E, APPROXIMATELY 205 NM WEST NORTHWEST OF NADI. ANIMATED HIMAWARI-9 INFRARED SATELLITE IMAGERY INDICATES A COMPACT BUT WELL-FORMED AREA OF DEEP CONVECTION EMBEDDED WITHIN THE SOUTH PACIFIC CONVERGENCE ZONE (SPCZ) AND SLOWLY DISSIPATING. THE FIRST FEW FRAMES OF DAYLIGHT IN THE VISIBLE CHANNEL REVEALS PULSATING OVERSHOOTING CLOUD TOPS NEAR THE CENTER OF THE CENTRAL DENSE OVERCAST, WITH FORMATIVE BANDING STRUCTURES TRYING TO BECOME ESTABLISHED. THE CURRENT INTENSITY IS ASSESSED TO BE 30 KTS BASED ON THE LIMITED DATA AVAILABLE. FAVORABLE ENVIRONMENTAL CONDITIONS CHARACTERIZED BY LOW VWS (05-10KT), GOOD DIVERGENT POLEWARD OUTFLOW, MOIST MID-LEVEL RELATIVE HUMIDITY, AND WARM SST (29-30C). ECMWF ENSEMBLE (ECENS) HAS APPROXIMATELY 30% OF MEMBERS STILL DEVELOPING THE SYSTEM OVER THE NEXT 36 HOURS, HOWEVER THE AVAILABLE 12Z GLOBAL MODELS ARE NOT HANDLING THE CURRENT ANALYSIS WELL, WHICH IS OFTEN TYPICAL OF SYSTEMS WITHIN THE SPCZ. THAT SAID, IT IS POSSIBLE INVEST 91P MAY HAVE ALREADY REACHED ITS PEAK AND HAS ONLY A LIMITED WINDOW FOR ADDITIONAL DEVELOPMENT AS IT TRACKS EAST SOUTHEASTWARD, DUE TO DRIER AIR THAT SHOULD BEGIN TO ENCROACH OVER THE NEXT 24 TO 36 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 28 TO 33 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1001 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS HIGH. THIS SUPERSEDES REF A (WTPN21 PGTW 272130). 3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY 292130Z. // NNNN