ABIO10 PGTW 132230
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE INDIAN OCEAN
/REISSUED/132230Z-141800ZJAN2021//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/132151ZJAN21//
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 99S) PREVIOUSLY LOCATED 
NEAR 13.1S 77.4E IS NOW LOCATED NEAR 13.5S 77.7E, APPROXIMATELY 475 
NM SOUTHEAST OF DIEGO GARCIA. ANIMATED ENHANCED INFRARED SATELLITE 
IMAGERY AND A 131336Z SSMIS 91GHZ MICROWAVE IMAGE REVEAL 
DISORGANIZED FORMATIVE BANDING WRAPPING INTO A WEAK LOW LEVEL 
CIRCULATION CENTER. A 131541Z METOP-B ASCAT PASS REVEALS AN 
ELONGATED, ASYMMETRIC LLCC WITH 25-30 KNOT WINDS TO THE SOUTH. 
INVEST 99S IS IN A FAVORABLE ENVIRONMENT FOR DEVELOPMENT WITH GOOD 
OUTFLOW ALOFT, LOW (10-15KTS) VERTICAL WIND SHEAR AND WARM (28-30C) 
SEA SURFACE TEMPERATURES. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 
INVEST 99S WILL TRACK WESTWARD AND CONSOLIDATE OVER THE NEXT 
SEVERAL DAYS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 
TO 20 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 UPGRADED TO MEDIUM.
      (2) THE AREA OF CONVECTION (INVEST 90S) PREVIOUSLY LOCATED 
NEAR 11.8S 97.3E IS NOW LOCATED NEAR 12.1S 97.2E, APPROXIMATELY 15 
NM EAST OF COCOS ISLAND. ANIMATED ENHANCED INFRARED SATELLITE 
IMAGERY AND A 131541Z MHS 89GHZ MICROWAVE IMAGE REVEAL A 
CONSOLIDATING SYSTEM WITH BUILDING DEEP CONVECTION OVERHEAD AND 
IMPROVING CONVECTIVE BANDING OVER THE WESTERN SEMICIRCLE WRAPPING 
INTO A TIGHTENING CENTER. SURFACE OBSERVATIONS FROM THE COCOS 
ISLANDS (YPCC) INDICATE SOUTHERLY WINDS AT 27KTS WITH SLP 1004MB 
(3MB 24HR PRESSURE DECREASE). A 131425Z METOP-A ASCAT PASS SHOWS A 
TIGHT LLCC WITH 20-25 KNOT WRAPPING WINDS AND SMALL AREA OF 30-35 
KNOT WINDS TO THE SOUTHWEST. INVEST 90S IS IN A FAVORABLE 
ENVIRONMENT FOR DEVELOPMENT WITH GOOD POLEWARD OUTFLOW ALOFT, 
MODERATE (20-25KTS) VERTICAL WIND SHEAR, AND WARM (28-30C) SEA 
SURFACE TEMPERATURES. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 
INVEST 90S WILL TRACK SOUTHWESTWARD,INTENSIFYING TO WARNING 
THRESHOLD  WITHIN THE NEXT 24-36 HOURS. MAXIMUM SUSTAINED SURFACE 
WINDS ARE ESTIMATED AT 25 TO 30 KNOTS. 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 
UPGRADED TO HIGH. SEE REF A (WTXS21 PGTW 132200) FOR FURTHER 
DETAILS.
      (3) NO OTHER SUSPECT AREAS.
   C. SUBTROPICAL SYSTEM SUMMARY: NONE.
3. JUSTIFICATION FOR REISSUE: UPGRADED AREA IN PARA 2.B.(2) TO 
HIGH AND UPGRADED AREA IN PARA 2.B.(1) TO MEDIUM.//
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