ABIO10 PGTW 280530
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE INDIAN OCEAN
/REISSUED/280530Z-281800ZSEP2021//
RMKS/
1. NORTH INDIAN OCEAN AREA (MALAY PENINSULA WEST TO COAST OF AFRICA):
   A. TROPICAL CYCLONE SUMMARY: NONE.
   B. TROPICAL DISTURBANCE SUMMARY:
      (1) AN AREA OF CONVECTION (INVEST 98B) HAS PERSISTED NEAR 
13.1N 89.0E, APPROXIMATELY 39.8 NM EAST OF KOLKATA. MAXIMUM 
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 27 TO 33 KNOTS. ANIMATED 
VISIBLE IMAGERY SHOWS THAT INVEST 98B HAS RAPIDLY CONSOLIDATED INTO 
A COMPACT TROPICAL DEPRESSION OVER THE PAST SIX HOURS. ANIMATED 
RADAR DATA FROM INDIA AND BANGLADESH INDICATE THAT A WELL DEFINED 
LOW LEVEL CIRCULATION CENTER (LLCC) HAS FORMED JUST SOUTH OF THE 
COASTLINE OF BANGLADESH. A 280246Z ASCAT-B PASS INDICATED A COMPACT 
LLCC SURROUNDED BY 25 KNOT WINDS, WITH A PATCH OF 35-40 KNOT WINDS 
IN THE EASTERN SEMICIRCLE UNDER DEEP, FLARING CONVECTION. THE SYSTEM 
IS EXPECTED TO MAKE LANDFALL WITHIN THE NEXT HOUR TO TWO TO THE 
SOUTHEAST OF KOLKATA AS A HIGH-END TROPICAL DEPRESSION WITH WIND 
GUSTS ABOVE TROPICAL STORM STRENGTH. ONCE ASHORE, THE SYSTEM SHOULD 
RAPIDLY DISSIPATE. THE ENVIRONMENT IS CURRENTLY FAVORABLE, WITH VERY 
WARM SSTS, LOW TO MODERATE SHEAR AND GOOD DIFFLUENT OUTFLOW TO THE 
WEST. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1000 MB. 
THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE 
WITHIN THE NEXT 24 HOURS IS MEDIUM.
      (2) NO OTHER SUSPECT AREAS.
   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: NONE.
   C. SUBTROPICAL SYSTEM SUMMARY: NONE.
3. JUSTIFICATION FOR REISSUE: UPGRADED AREA IN PARA. 1.B.(1) TO 
MEDIUM.//
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