WTXS21 PGTW 071100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 97S) REISSUED// REF/A/JOINT TYPHOON WRNCEN PEARL HARBOR HI/071051Z MAR 22// AMPN/REF A IS TROPICAL CYCLONE FORMATION ALERT (WTXS21 PGTW 071100)// RMKS/ 1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN 120 NM EITHER SIDE OF A LINE FROM 15.2S 52.2E TO 15.1S 48.1E 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 20 TO 25 KNOTS. METSAT IMAGERY AT 070600Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 15.2S 52.1E. THE SYSTEM IS MOVING WESTWARD AT 03 KNOTS. 2. REMARKS:THE AREA OF CONVECTION (INVEST 97S) PREVIOUSLY LOCATED NEAR 15.2S 52.4E IS NOW LOCATED NEAR 15.2S 52.1E, APPROXIMATELY 233NM NORTHEAST OF TOAMASINA, MADAGASCAR. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A WELL DEFINED LOW LEVEL CIRCULATION CENTER (LLCC) WITH FRAGMENTED CONVECTIVE BANDING WRAPPING INTO THE LLCC FROM THE SOUTH, WHILE A RECENT 070544Z ASCAT PARTIAL PASS REVEALS A DOMINATE SWATH OF 20 TO 25 KNOT WINDS WRAPPING INTO THE LLCC FROM THE SOUTH AND WEST. ANALYSIS INDICATES THE ENVIRONMENT IS OVERALL FAVORABLE FOR TROPICAL CYCLONE DEVELOPMENT WITH FEEBLE RADIAL OUTFLOW, LOW VERTICAL WIND SHEAR (10-15KTS), AND WARM SEA SURFACE TEMPERATURES (28-29C). GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 97S WILL REMAIN GENERALLY QUASI-STATIONARY IN THE NEAR-TERM AND THEN MEANDER SLOWLY WEST TOWARDS MADAGASCAR OVER THE NEXT 24 TO 36. HOWEVER THE TIMING OF WHEN 97S REACHES WARNING CRITERIA DIFFERS, WITH MESOSCALE MODELS INCLUDING HWRF AND COAMPS-TC INTENSIFYING THE DISTURBANCE TO TROPICAL STORM STRENGTH WITHIN 24 HOURS, PRIOR TO LANDFALL, WHILE ECMWF AND OTHER DETERMINISTIC MODELS HOLD THE INTENSITY BELOW TROPICAL STORM STRENGTH THROUGH LANDFALL, FOLLOWED BY WEAKENING THEREAFTER. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1004 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS HIGH. THIS SUPERSEDES REF A. 3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY 081100Z. // NNNN