ABIO10 PGTW 201800
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE INDIAN
/OCEAN/201800Z-211800ZSEP2021//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/201821ZSEP2021//
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 90S) PREVIOUSLY LOCATED 
NEAR 9.9S 84.1E IS NOW LOCATED NEAR 9.5S 84.2E. ANIMATED ENHANCED 
INFRARED IMAGERY DEPICTS AN EXPOSED LOW LEVEL CIRCULATION CENTER 
(LLCC) WITH FLARING CONVECTION DISPLACED TO THE SOUTH. A 1454 ASCAT-
A IMAGE SHOWS WRAPPING 25 KT WINDS IN THE SOUTHERN SEMICIRCLE. 
ENVIRONMENTAL ANALYSIS REVEALS MARGINALLY UNFAVORABLE CONDITIONS 
WITH HIGH (30-40 KT) VWS OFFSET BY PRONOUNCED RADIAL OUTFLOW AND 
HIGH SEA SURFACE TEMPERATURES (29-30C). GLOBAL MODELS ARE IN 
AGREEMENT THAT INVEST 90S WILL TRACK TO THE SOUTHWEST WITH THE GFS 
DETERMINISTIC MODEL SHOWING THE MOST AGGRESSIVE PREDICTION. MAXIMUM 
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 23 TO 27 KNOTS. MINIMUM SEA 
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1007 MB. THE POTENTIAL FOR 
THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 
HOURS IS HIGH. SEE REF A (WTXS21 PGTW 201830) FOR FURTHER DETAILS.
      (2) NO OTHER SUSPECT AREAS.
   C. SUBTROPICAL SYSTEM SUMMARY: NONE.//
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