ABIO10 PGTW 301800 
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE INDIAN
OCEAN/301800Z-311800ZOCT2021//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/292051ZOCT2021//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.//
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: NONE.
   B. TROPICAL DISTURBANCE SUMMARY:
      (1) THE AREA OF CONVECTION (INVEST 93S) PREVIOUSLY LOCATED 
NEAR 10.0S 86.6E IS NOW LOCATED NEAR 11.9S 82.9E, APPROXIMATELY 663 
NM EAST-SOUTHEAST OF DIEGO GARCIA. ANIMATED ENHANCED INFRARED (EIR) 
SATELLITE IMAGERY AND A 301253Z SSMIS 91GHZ IMAGE REVEAL A BROAD LOW 
LEVEL CIRCULATION CENTER DEFINED BY SHALLOW BANDING WITH DEEP 
CONVECTION CONFINED TO THE SOUTHWEST. A 301543Z ASCAT-B SHOWS AN 
ELONGATED DEFINED CIRCULATION WITH LIMITED GALE FORCE WINDS TO THE 
SOUTHWEST AND EXTENSIVE 20-25KT WINDS ENCAPSULATING THE REMAINING 
QUADRANTS. FOR THE ENVIRONMENTAL ANALYSIS, THERE IS MODERATE TO HIGH 
(20-30 KNOTS) VERTICAL WIND SHEAR WHICH IS OFFSET BY ROBUST POLEWARD 
OUTFLOW. ADDITIONALLY, THERE IS SIGNIFICANT DRY AIR ENTRAINMENT 
THROUGHOUT THE MID-LEVELS THAT IS HINDERING CONVECTIVE DEVELOPMENT. 
OVERALL, SST VALUES AT 27-28C ARE CONDUCIVE. GLOBAL MODELS ARE IN 
AGREEMENT THAT INVEST 93S WILL TRACK WESTWARD AND CONSOLIDATE OVER 
THE NEXT 24 HOURS. 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 HIGH. SEE REF A (WTXS21 
PGTW 292100) FOR FURTHER DETAILS.     
      (2) NO OTHER SUSPECT AREAS.
   C. SUBTROPICAL SYSTEM SUMMARY: NONE.//
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