WTPN21 PGTW 081400 COR MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE FORMATION ALERT CORRECTED// RMKS/ 1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN 145 NM EITHER SIDE OF A LINE FROM 15.7N 112.9E TO 20.4N 112.7E 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 23 TO 28 KNOTS. METSAT IMAGERY AT 081200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 16.0N 112.9E. THE SYSTEM IS MOVING NORTH-NORTHEASTWARD AT 04 KNOTS. 2. REMARKS: THE AREA OF CONVECTION (INVEST 97W) PREVIOUSLY LOCATED NEAR 15.3N 112.8E IS NOW LOCATED NEAR 16.0N 112.9E, APPROXIMATELY 384 NM SOUTH OF HONG KONG. ANIMATED ENHANCED INFRARED (EIR) SATELLITE AND MICROWAVE IMAGERY DEPICT A BROAD, DISORGANIZED MONSOON DEPRESSION IN THE SOUTH CHINA SEA WHICH IS STEADILY CONSOLIDATING. THE RADIUS OF MAXIMUM WINDS (RMW) WAS PREVIOUSLY ESTIMATED TO BE GREATER THAN 150NM, BUT A 081200Z SHIP OBSERVATION OF 32 KNOTS APPROXIMATELY 110NM TO THE SOUTHWEST SUGGESTS THE RMW HAS STARTED TO SHRINK DOWN, APPROACHING THE TRANSITION POINT TO A TROPICAL DEPRESSION. A 081031Z 91GHZ SSMIS MICROWAVE REVEALED MULTIPLE WEST-EAST AND NORTH-SOUTH ORIENTED CONVECTIVE BANDS BUT AS OF YET NO DISTINCT CENTER OF CIRCULATION. MEANWHILE, ANIMATED EIR AND MODEL FIELDS SUGGEST A SECONDARY CIRCULATION CENTER DEVELOPING NEAR 17.5N 118.0E, WHICH IS EXPECTED TO RAPIDLY MOVE WESTWARD AND MERGE WITH 97W AS IT MOVES TO THE NORTHEAST. SHIP OBSERVATIONS FROM THE BROADER REGION INDICATE A VERY BROAD WIND FIELD WITH WINDS UP TO 25-30 KNOTS, EXTENDING IN A BAND TO THE NORTH AS FAR AS 20N AND TO THE SOUTH TO NEAR 10N. ENVIRONMENTAL ANALYSIS INDICATES GOOD OUTFLOW IN THE MID AND UPPER LEVELS, LOW (5-10 KNOTS) VWS IN THE IMMEDIATE VICINITY, AND WARM (29-30C) SEA SURFACE TEMPERATURES. OVERALL CONDITIONS ARE RIPE FOR DEVELOPMENT, YET A REGION OF UNFAVORABLE SHEAR (20-30KT) STRETCHING FROM HAINAN TO THE LUZON STRAIT, AND THE SLOW RATE OF CONSOLIDATION ARE PROVING TO BE STIFF BARRIERS TO MORE RAPID DEVELOPMENT. DETERMINISTIC AND ENSEMBLE MODELS AGREE THAT THE CIRCULATION ASSOCIATED WITH 97W WILL MAINTAIN A BROAD WIND FIELD AS IT STARTS ITS NORTHERLY TRACK, MERGE WITH THE VORTICITY CENTER CURRENTLY DEVELOPING TO THE NORTHEAST AND CONSOLIDATE JUST ENOUGH BEFORE LANDFALL TO MEET THE CRITERIA FOR A TROPICAL DEPRESSION. INTENSITY GUIDANCE SHOWS STEADY INTENSIFICATION TO A WEAK TO MODERATE TROPICAL STORM STRENGTH SYSTEM PRIOR TO LANDFALL. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 23 TO 28 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1000 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS UPGRADED TO HIGH. 3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY 091430Z. 4. JUSTIFICATION FOR CORRECTION: CORRECTED INVEST NUMBER FROM 98W TO 97W ON GRAPHIC. // NNNN