ABIO10 PGTW 081800
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE INDIAN
/OCEAN/081800Z-091800ZAPR2021//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/081352ZAPR2021//
REF/B/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/081351ZAPR2021//
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 08APR21 1500Z, TROPICAL CYCLONE 27S (TWENTYSEVEN) WAS 
LOCATED NEAR 14.9S 106.2E, APPROXIMATELY 628 NM NORTHWEST OF 
LEARMONTH, AUSTRALIA, AND HAD TRACKED NORTHWESTWARD AT 07 KNOTS OVER 
THE PAST SIX HOURS. MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED 
AT 35 KNOTS GUSTING TO 45 KNOTS. SEE REF A (WTXS32 PGTW 081500) FOR 
FURTHER DETAILS.
      (2) AT 08APR21 1500Z, TROPICAL CYCLONE 26S (SEROJA) WAS 
LOCATED NEAR 18.0S 111.1E, APPROXIMATELY 315 NM NORTH-NORTHWEST OF 
LEARMONTH, AUSTRALIA, AND HAD TRACKED SOUTH- SOUTHWESTWARD AT 09 
KNOTS OVER THE PAST SIX HOURS. MAXIMUM SUSTAINED SURFACE WINDS WERE 
ESTIMATED AT 55 KNOTS GUSTING TO 70 KNOTS. SEE REF B (WTXS31 PGTW 
081500) FOR FURTHER DETAILS.
      (3) NO OTHER TROPICAL CYCLONES.
   B. TROPICAL DISTURBANCE SUMMARY:
      (1) THE AREA OF CONVECTION (INVEST 91S) PREVIOUSLY LOCATED 
NEAR 9.7S 91.4E IS NOW LOCATED NEAR 9.9S 93.9E, APPROXIMATELY 221 NM 
NORTH-NORTHWEST OF COCOS ISLANDS, AUSTRALIA. ANIMATED ENHANCED 
INFRARED (EIR) SATELLITE IMAGERY REVEALS CYCLING CONVECTION TO THE 
SOUTHWEST OF AN OBSCURE LOW LEVEL CIRCULATION (LLC). INVEST 91S IS 
IN A MARGINAL ENVIRONMENT FOR TROPICAL DEVELOPMENT WITH GOOD 
POLEWARD OUTFLOW ALOFT, WARM (29-30C) SEA SURFACE TEMPERATURES 
OFFSET BY STRONG (25-30KTS) VERTICAL WIND SHEAR (VWS). GLOBAL MODELS 
ARE IN GOOD AGREEMENT THAT INVEST 91S WILL CONSOLIDATE AND INTENSIFY 
OVER THE NEXT 48-72 HOURS AS IT TRACKS TO THE SOUTHEAST UNDER AN 
AREA OF MODERATE (15-25KTS) VWS. MAXIMUM SUSTAINED SURFACE WINDS ARE 
ESTIMATED AT 25 TO 30 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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