ABIO10 PGTW 091800
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE INDIAN 
OCEAN/091800Z-101800ZAPR2021//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/091352ZAPR2021//
REF/B/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/091351ZAPR2021//
NARR/REFS A AND B ARE TROPICAL CYCLONE WARNINGS.//
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 09APR21 1200Z, TROPICAL CYCLONE 27S (ODETTE) WAS 
LOCATED NEAR 15.6S 111.0E, APPROXIMATELY 439 NM NORTH-NORTHWEST OF 
LEARMONTH, AUSTRALIA, AND HAD TRACKED EAST-SOUTHEASTWARD AT 19 KNOTS 
OVER THE PAST SIX HOURS. MAXIMUM SUSTAINED SURFACE WINDS WERE 
ESTIMATED AT 40 KNOTS GUSTING TO 50 KNOTS. SEE REF A (WTXS32 PGTW 
091500) FOR FURTHER DETAILS.
      (2) AT 09APR21 1200Z, TROPICAL CYCLONE 26S (SEROJA) WAS 
LOCATED NEAR 20.2S 108.9E, APPROXIMATELY 317NM WEST-NORTHWEST OF 
LEARMONTH, AUSTRALIA, AND HAS TRACKED SOUTHWESTWARD AT 07 KNOTS OVER 
THE PAST SIX HOURS. MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED 
AT 55 KNOTS GUSTING TO 70 KNOTS. SEE REF B (WTXS31 PGTW 091500) FOR 
FURTHER DETAILS.
      (3) NO OTHER TROPICAL CYCLONES.
   B. TROPICAL DISTURBANCE SUMMARY:
      (1) THE AREA OF CONVECTION (INVEST 91S) PREVIOUSLY LOCATED 
NEAR 9.9S 93.9E IS NOW LOCATED NEAR 11.7S 97.5E, APPROXIMATELY 46 NM 
NORTHEAST OF THE COCOS ISLANDS. ANIMATED ENHANCED INFRARED (EIR) 
SATELLITE IMAGERY AND A 091013Z SSMIS 91 GHZ MICROWAVE IMAGE SHOW 
FLARING CONVECTION IN THE SOUTHERN PERIPHERY OF A BROAD, ELONGATED 
LOW LEVEL CIRCULATION (LLC). INVEST 91S IS IN A MARGINAL ENVIRONMENT 
FOR TROPICAL DEVELOPMENT WITH MINIMAL POLEWARD OUTFLOW AND MODERATE 
(15-20KTS) VERTICAL WIND SHEAR OFFSET BY WARM (28-29C) SEA SURFACE 
TEMPERATURES. GLOBAL MODELS ARE IN GENERAL AGREEMENT THAT INVEST 91S 
WILL INTENSIFY SLIGHTLY OVER THE NEXT 48-72 HOURS AS IT TRACKS TO 
THE SOUTHEAST. 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 REMAINS LOW.
      (2) NO OTHER SUSPECT AREAS.
   C. SUBTROPICAL SYSTEM SUMMARY: NONE.//
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