WTPN21 PGTW 240300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 98W)// RMKS/ 1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN 180 NM EITHER SIDE OF A LINE FROM 7.6N 150.4E TO 16.2N 145.4E 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 19 TO 24 KNOTS. METSAT IMAGERY AT 240200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 8.4N 150.0E. THE SYSTEM IS MOVING NORTH-NORTHWESTWARD AT 04 KNOTS. 2. REMARKS: THE AREA OF CONVECTION (INVEST 98W) PREVIOUSLY LOCATED NEAR 8.0N 151.2E IS NOW LOCATED NEAR 8.4N 150.0E, APPROXIMATELY 424 NM SOUTHEAST OF GUAM. ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND A 232303Z GMI 89GHZ SATELLITE IMAGERY DEPICTS A BROAD AREA OF FLARING CONVECTION, WITH A WEAKLY DEFINED LOW LEVEL CIRCULATION CENTER, AND AN AREA OF STRONG WINDS NOW WRAPPING AROUND THE SYSTEM. ENVIRONMENTAL ANALYSIS REVEALS THAT INVEST 98W IS IN A FAVORABLE ENVIRONMENT FOR DEVELOPMENT WITH, WARM SEA SURFACE TEMPERATURES (30C), GOOD RADIAL OUTFLOW ALOFT, AND LOW TO MODERATE VERTICAL WIND SHEAR (15-20KTS) GLOBAL MODELS ARE IN GOOD AGREEMENT THAT INVEST 98W WILL GENERALLY TRACK NORTHWESTWARD OVE THE NEXT 48 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 18 TO 23 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 IS HIGH. 3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY 250300Z.// NNNN