ABIO10 PGTW 031800 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE INDIAN /OCEAN/031800Z-041800ZMAR2021// REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/031352ZMAR2021// 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 03MAR21 1200Z, TROPICAL CYCLONE 22S (MARIAN) WAS LOCATED NEAR 19.3S 92.1E, APPROXIMATELY 1235 NM WEST OF LEARMONTH, AUSTRALIA, AND HAD TRACKED EAST-SOUTHEASTWARD AT 07 KNOTS OVER THE PAST SIX HOURS. MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED AT 50 KNOTS GUSTING TO 65 KNOTS. SEE REF A (WTXS31 PGTW 031500) FOR FURTHER DETAILS. (2) NO OTHER TROPICAL CYCLONES. B. TROPICAL DISTURBANCE SUMMARY: (1) THE AREA OF CONVECTION (INVEST 90S) PREVIOUSLY LOCATED NEAR 15.2S 65.6E IS NOW LOCATED NEAR 15.6S 67.4E, APPROXIMATELY 576 NM SOUTHWEST OF DIEGO GARCIA. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY AND A 031428Z SSMIS 91GHZ MICROWAVE IMAGE DEPICT FRAGMENTED FORMATIVE BANDING WRAPPING INTO AN ELONGATED LOW LEVEL CIRCULATION CENTER (LLCC) WITH FLARING CONVECTION IN THE EASTERN SEMICIRCLE. INVEST 90S IS IN A FAVORABLE ENVIRONMENT FOR DEVELOPMENT WITH GOOD OUTFLOW ALOFT, LOW (<15KTS) VERTICAL WIND SHEAR (VWS) AND WARM (29- 30C) SEA SURFACE TEMPERATURES. GLOBAL MODELS ARE IN GENERAL AGREEMENT THAT INVEST 90S WILL TRACK EAST-SOUTHEASTWARD AS IT SLOWLY CONSOLIDATES. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25 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 IS UPGRADED TO MEDIUM. (2) NO OTHER SUSPECT AREAS. C. SUBTROPICAL SYSTEM SUMMARY: NONE.// NNNN