WTPN21 PHNC 201000MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//SUBJ/TROPICAL CYCLONE FORMATION ALERT//RMKS/1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN100 NM EITHER SIDE OF A LINE FROM 18.6N 107.4W TO 22.2N 109.7WWITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFYISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.WINDS IN THE AREA ARE ESTIMATED TO BE 15 TO 20 KNOTS. METSAT IMAGERY AT 200930Z INDICATES THAT A CIRCULATION CENTER IS LOCATEDNEAR 19.0N 107.5W. THE SYSTEM IS MOVING NORTH-NORTHWESTWARD AT08 KNOTS