WTPN22 PGTW 290530 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 90W)// RMKS/ 1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN 120 NM EITHER SIDE OF A LINE FROM 6.6N 153.0E TO 9.1N 148.2E 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 6.8N 152.8E. THE SYSTEM IS MOVING WEST-NORTHWESTWARD AT 06 KNOTS. 2. REMARKS: THE AREA OF CONVECTION (INVEST 90W) PREVIOUSLY LOCATED NEAR 6.0N 153.6E IS NOW LOCATED NEAR 6.8N 152.8E, APPROXIMATELY 622 NM SOUTHEAST OF GUAM. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS MID TO UPPER LEVEL TURNING OVER AN ILL DEFINED LOW LEVEL CIRCULATION (LLC). A 290328Z AMSR2 89GHZ SATELLITE IMAGE DEPICTS AN IMPROVING CONVECTIVE STRUCTURE WITH THE DEEP CONVECTION DISPLACED TO THE WEST-SOUTHWEST OF THE LLC. ANALYSIS INDICATES A FAVORABLE ENVIRONMENT FOR DEVELOPMENT CHARACTERIZED BY WARM (30-31C) SEA SURFACE TEMPERATURES, A POINT SOURCE ALOFT, AND LOW (<15 KTS) VERTICAL WIND SHEAR (VWS). GLOBAL MODELS ARE IN FAIR AGREEMENT THAT INVEST 90W WILL POTENTIALLY GAIN INTENSITY OVER THE NEXT COUPLE OF DAYS AND THEN LOSE STRENGTH AS IT PROPAGATES NORTHWESTWARD, WITH THE EXCEPTION OF GFS, WHICH SHOWS A STRENGTHENING AND CONSOLIDATION BEYOND TAU 72. 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 300530Z.// NNNN