WTPN21 PGTW 300530 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 90W)// REF/A/JOINT TYPHOON WRNCEN PEARL HARBOR HI/290521ZMAY21// AMPN/REF IS TROPICAL CYCLONE FORMATION ALERT (WTPN22 PGTW 290530)// RMKS/ 1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN 120 NM EITHER SIDE OF A LINE FROM 7.2N 149.3E TO 9.6N 145.6E 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 18 TO 23 KNOTS. METSAT IMAGERY AT 300000Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 7.4N 149.0E. THE SYSTEM IS MOVING WEST-NORTHWESTWARD AT 12 KNOTS. 2. REMARKS: THE AREA OF CONVECTION (INVEST 90W)PREVIOUSLY LOCATED NEAR 6.8N 152.8E IS NOW LOCATED NEAR 7.4N 149.0E, APPROXIMATELY 445 NM SOUTHEAST OF GUAM. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS UPPER LEVEL TURNING AND FLARING CONVECTION WITHOUT A DISCERNIBLE LOW LEVEL CIRCULATION CENTER (LLCC). ANALYSIS INDICATES A FAVORABLE ENVIRONMENT FOR DEVELOPMENT CHARACTERIZED BY LOW TO MODERATE (10-20 KTS) VERTICAL WIND SHEAR (VWS), EQUATORWARD OUTFLOW, AND WARM (30-31C) SEA SURFACE TEMPERATURES (SST). GLOBAL MODELS GENERALLY AGREE THAT INVEST 90W WILL LOSE STRENGTH AS IT PROPAGATES NORTHWESTWARD. HWRF INDICATES MINOR DEVELOPMENT THE NEXT 48 HOURS AND REACHING WARNING CRITERIA BY TAU 72. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 18 TO 23 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1005 MB. IN CONSIDERATION OF THE FAVORABLE ENVIRONMENT, THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS HIGH. THIS SUPERSEDES REF A. 3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY 310530Z. // NNNN