WTPN21 PHNC 211300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE FORMATION ALERT// RMKS/ 1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN 090 NM EITHER SIDE OF A LINE FROM 16.4N 103.9W TO 17.8N 108.6W 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 20 TO 25 KNOTS. METSAT IMAGERY AT 211200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 16.3N 104.1W. THE SYSTEM IS MOVING WESTWARD AT 11 KNOTS. 2. REMARKS: AN AREA OF CONVECTION (INVEST 96E) IS LOCATED NEAR 16.3N 104.1W, APPROXIMATELY 1213 NM SOUTHEAST OF SAN DIEGO, CA. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY AND A 210852Z GMI 89 GHZ GMI IMAGE DEPICT DEEP CONVECTION WITH SHALLOW RAIN BANDS WRAPPING INTO A WELL- DEFINED LOW LEVEL CIRCULATION (LLC). ENVIRONMENTAL ANALYSIS INDICATES A FAVORABLE AREA FOR DEVELOPMENT DEFINED BY FAIR WESTWARD OUTFLOW, LOW (5- 10KT) VERTICAL WIND SHEAR, AND WARM (28-29C) SEA SURFACE TEMPERATURES. GLOBAL MODELS ARE IN AGREEMENT THAT INVEST 96E WILL TRACK GENERALLY WESTWARD OVER THE NEXT 72-96 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1007 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 221300Z. // NNNN