ABIO10 PGTW 101800 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE INDIAN OCEAN/101800Z- 111800ZAPR2023// REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/101351ZAPR2023// 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 10APR23 1200Z, TROPICAL CYCLONE 18S (EIGHTEEN) WAS LOCATED NEAR 13.4S 122.5E, APPROXIMATELY 717 NM NORTHEAST OF LEARMONTH, AUSTRALIA, AND HAD TRACKED WEST- SOUTHWESTWARD AT 06 KNOTS OVER THE PAST SIX HOURS. MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED AT 45 KNOTS GUSTING TO 55 KNOTS. SEE REF A (WTXS31 PGTW 101500) FOR FURTHER DETAILS. (2) NO OTHER TROPICAL CYCLONES. B. TROPICAL DISTURBANCE SUMMARY: NONE. C. SUBTROPICAL SYSTEM SUMMARY: NONE.// NNNN