WTPN21 PGTW 202200 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 90W)// RMKS/ 1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN 125 NM EITHER SIDE OF A LINE FROM 18.2N 122.6E TO 22.7N 122.3E 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 15 TO 20 KNOTS. METSAT IMAGERY AT 201800Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 18.4N 122.6E. THE SYSTEM IS MOVING NORTHWARD AT 09 KNOTS. 2. REMARKS: THE AREA OF CONVECTION (INVEST 90W) PREVIOUSLY LOCATED NEAR 17.5N 122.7E IS NOW LOCATED NEAR 18.4N 122.6E, APPROXIMATELY 285 NM SOUTH-SOUTHEAST OF KAOHSIUNG, TAIWAN. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY AND A 202023Z SSMIS 91GHZ MICROWAVE IMAGE DEPICT A CONSOLIDATING LOW LEVEL CIRCULATION CENTER (LLCC) WITH FLARING CONVECTION ALONG THE EASTERN PERIPHERY OF THE DISTURBANCE. UPPER-LEVEL ANALYSIS SHOWS 90W TO BE IN A FAVORABLE ENVIRONMENT FOR DEVELOPMENT WITH GOOD EQUATORWARD OUTFLOW, MODERATE VWS (15-20KT), AND WARM SST (30-31C). GLOBAL MODELS ARE IN STRONG AGREEMENT THAT 90W WILL TRACK NORTH- NORTHWESTWARD INTO A REGION OF LOWER VERTICAL WIND SHEAR AND GRADUALLY INTENSIFY. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1006 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 212200Z. // NNNN