WTPN21 PHNC 121530 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE FORMATION ALERT// RMKS/ 1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN 105 NM EITHER SIDE OF A LINE FROM 11.6N 121.3W TO 12.2N 126.4W 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 121206Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 11.7N 122.5W. THE SYSTEM IS MOVING WEST-NORTHWESTWARD AT 13 KNOTS. 2. REMARKS: THE AREA OF CONVECTION (INVEST 92E) HAS PERSISTED NEAR 11.7N 122.5W, APPROXIMATELY 1283 NM SOUTHWEST OF SAN DIEGO. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS DEEPENING CONVECTION CONSOLIDATING AROUND A LOW LEVEL CIRCULATION (LLC). A 1222Z 91H GHS SSMIS MICROWAVE PASS SHOWS STRONG CONVECTIVE BANDS DISPLACED TO THE SOUTHWEST AND NORTH OF THE LLC. UPPER LEVEL ANALYSIS INDICATES THE DISTURBANCE IS LOCATED IN AN AREA OF FAVORABLE VWS AND FAIR OUTLFOW. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 18 TO 23 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1005 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 131530Z. // NNNN