ABIO10 PGTW 050200 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE INDIAN OCEAN /REISSUED/050200Z-051800ZFEB2021// REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/041951ZFEB2021// AMPN/REF A IS A TROPICAL CYCLONE WARNING.// RMKS/ 1. NORTH INDIAN OCEAN AREA (MALAY PENINSULA WEST TO COAST OF AFRICA): A. TROPICAL CYCLONE SUMMARY: NONE. B. TROPICAL DISTURBANCE SUMMARY: NONE. C. SUBTROPICAL SYSTEM SUMMARY: NONE. 2. SOUTH INDIAN OCEAN AREA (135E WEST TO COAST OF AFRICA): A. TROPICAL CYCLONE SUMMARY: (1) AT 04FEB21 1800Z, TROPICAL CYCLONE 18S (EIGHTEEN) WAS LOCATED NEAR 24.8S 113.1E, APPROXIMATELY 160 NM SOUTH-SOUTHWEST OF LEARMONTH, AUSTRALIA, AND HAD TRACKED SOUTHWESTWARD AT 03 KNOTS OVER THE PAST SIX HOURS. MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED AT 35 KNOTS GUSTING TO 45 KNOTS. SEE REF A (WTXS31 PGTW 042100) FOR FURTHER DETAILS. (2) NO OTHER TROPICAL CYCLONES. B. TROPICAL DISTURBANCE SUMMARY: (1) THE AREA OF CONVECTION (INVEST 90S) PREVIOUSLY LOCATED NEAR 11.2S 81.3E IS NOW LOCATED NEAR 11.6S 81.4E, APPROXIMATELY 900 NM WEST OF COCOS ISLANDS. ANIMATED ENHANCED MULTISPECTRAL IMAGERY AND A 042223Z SSMIS 85 GHZ SATELLITE IMAGE DEPICTS A CONSOLIDATING LOW LEVEL CIRCULATION CENTER WITH FLARING CONVECTION ALOFT. UPPER LEVEL ANALYSIS INDICATES 90S IS IN A FAVORABLE ENVIRONMENT FOR DEVELOPMENT WITH GOOD DIVERGENCE ALOFT, (MODERATE 20-25KTS) VERTICAL WIND SHEAR AND WARM (29-30C) SEA SURFACE TEMPERATURES. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 90S WILL GRADUALLY DEVELOP AND CONTINUE TO TRACK EASTWARD OVER THE NEXT 24 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1003 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS UPGRADED TO MEDIUM. (2) NO OTHER SUSPECT AREAS. C. SUBTROPICAL SYSTEM SUMMARY: NONE. 3. JUSTIFICATION FOR REISSUE: UPGRADED AREA IN PARA. 2.B.(1) TO MEDIUM.// NNNN