SUBJ/TROPICAL CYCLONE FORMATION ALERT REISSUED // WTPN21 PGTW 272100 REF/A/JOINT TYPHOON WRNCEN PEARL HARBOR HI/262151Z JUL 22// AMPN/REF IS TROPICAL CYCLONE FORMATION ALERT (WTPN21 PGTW 262200)// RMKS/ 1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN 120 NM EITHER SIDE OF A LINE FROM 18.4N 140.4E TO 28.0N 132.1E 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 271800Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 18.7N 140.1E. THE SYSTEM IS MOVING NORTH-NORTHWESTWARD AT 10 KNOTS. 2. REMARKS: THE AREA OF CONVECTION (INVEST 93W) PREVIOUSLY LOCATED NEAR 16.1N 142.6E IS NOW LOCATED NEAR 18.7N 140.1E, APPROXIMATELY 415 NM NORTHWEST OF GUAM. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY AND A 271632Z AMSR2 PASS DEPICT BROAD FLARING CONVECTION MOSTLY CONFINED TO THE NORTHEAST AND SOUTHERN QUADRANTS OBSCURING AN ASSESSED LOW LEVEL CIRCULATION (LLC). ENVIRONMENTAL ANALYSIS INDICATES THE INVEST IS IN A MODERATELY FAVORABLE AREA FOR DEVELOPMENT DEFIND BY LOW (10-15KTS) VERTICAL WIND SHEAR, WARM (29-30C) SEA SURFACE TEMERATURES. ADDITIONALLY, A WESTWARD TRANSITING TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) CELL IS ENHANCING POLEWARD AND EQUATORWARD OUTFLOW, YET IS OFFSET BY SOME DRY AIR ENTRAINMENT. OTHER SCATTEROMETRY SHOWS A SHARP TROUGH AT THE SURFACE WITH 20 KNOT WINDS IN THE NORTHEAST AND SOUTHERN QUADRANTS LIKELY ASSOCIATED WITH THUNDERSTORM ACTIVITY. NUMERICAL MODELS ARE IN GENERAL AGREEMENT THAT THE SYSTEM WILL TRACK NORTHWESTWARD AND DEEPEN OVER THE NEXT 24-48 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 18 TO 23 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1002 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS HIGH. 3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY 282100Z. // NNNN