WTPN21 PGTW 290300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE FORMATION ALERT// RMKS/ 1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN 120 NM EITHER SIDE OF A LINE FROM 15.1N 116.9E TO 17.7N 114.8E 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 290000Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 15.1N 116.9E. THE SYSTEM IS MOVING SOUTHEASTWARD AT 04 KNOTS. 2. REMARKS: THE AREA OF CONVECTION (INVEST 97W) PREVIOUSLY LOCATED NEAR 15.5N 116.5E IS NOW LOCATED NEAR 15.1N 116.9E, APPROXIMATELY 460 NM SOUTH-SOUTHEAST OF HONG KONG. ANIMATED ENHANCED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A CONSOLIDATED LOW LEVEL CIRCULATION CENTER (LLCC)BECOMING MORE ORGANIZED WITH DEEPENING CONVECTION. 282049 SSMIS 91GHZ SHOWS A BROAD, OPEN, SYMETRICAL CIRCULATION WITH A MONSOON DEPRESSION-LIKE SIGNATURE. THE MOST RECENT JTWC UPPER LEVEL STREAM LINE ANALYSIS REVEALS A POINT SOURCE NORTHEAST OF INVEST 97W THAT IS ENHANCING EQUATORWARD OUTFLOW. ENVIRONMENTAL ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH LOW (10-15 KNOT) VWS, MODERATE DIVERGENCE ALOFT, AND WARM (30C) SEA SURFACE TEMPERATURES. THE MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 999MB. GFS IS THE MOST AGGRESSIVE, BUT GLOBAL MODELS ARE IN GOOD AGREEMENT ON SLOW DEVELOPMENT ALONG A NORTHWESTWARD TRACK TO THE COAST OF SOUTHEAST CHINA, WITH INTENSIFICATION GRADUALLY UP TO LANDFALL. 3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY 300300Z. // NNNN