ABIO10 PGTW 031430
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE INDIAN OCEAN
/REISSUED/031430Z-031800ZAPR2021//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/031351ZAPR2021//
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:
      (1) THE AREA OF CONVECTION (INVEST 90B) PREVIOUSLY LOCATED 
NEAR 12.2N 97.3E HAS DISSIPATED AND IS NO LONGER SUSPECT FOR THE 
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE IN THE NEXT 24 HOURS.
      (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:
      (1) THE AREA OF CONVECTION (INVEST 99S) PREVIOUSLY LOCATED 
NEAR 11.0S 122.3E IS NOW LOCATED NEAR 10.7S 123.8E, APPROXIMATELY 
209 NM NORTH OF BROWSE ISLAND, AUSTRALIA. ANIMATED MULTISPECTRAL 
SATELLITE IMAGERY AND A 031054Z SSMIS F-17 91GHZ MICROWAVE IMAGE 
DEPICT FLARING DEEP CONVECTION CIRCLING A PARTIALLY OBSCURED LOW 
LEVEL CIRCULATION CENTER (LLCC) WITH FRAGMENTED FORMATIVE BANDING 
WRAPPING IN FROM THE SOUTH AND EAST. A 031150Z METOP-A ASCAT PASS 
REVEALS A TIGHT LLCC WITH A SMALL, BUT ENHANCED, WIND FIELD OF 20 TO 
30 KNOTS WITH A COUPLE 35 KNOT WIND BARBS TO THE NORTH. 99S IS 
CURRENTLY IN A FAVORABLE ENVIRONMENT WITH WARM (30 CELSIUS) SEA 
SURFACE TEMPERATURES, LOW (10 TO 15 KNOT) VERTICAL WIND SHEAR, AND 
GOOD RADIAL OUTFLOW. GLOBAL MODELS ARE IN GENERAL AGREEMENT THAT 99S 
WILL REMAIN LARGELY QUASISTATIONARY WITH SLIGHTLY NORTHEASTWARD 
MOVEMENT BEFORE TURNING 180 DEGREES TO THE SOUTHWEST IN AROUND 18 TO 
24 HOURS. IN THAT TIME, 99S WILL CONTINUE TO INTENSIFY; HOWEVER, 
MODELS DISAGREE ON TIMING WITH THE MAJORITY PREDICTING 99S REACHING 
WARNING THRESHOLD IN APPROXIMATELY 36 HOURS, WHILE ECMWF, THE ONLY 
OUTLIER, PREDICTS A QUICKER INTENSIFICATION, REACHING WARNING 
THRESHOLD IN 12 TO 24 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE 
ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED 
TO BE NEAR 999 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 031400) FOR FURTHER DETAILS.
      (2) THE AREA OF CONVECTION (INVEST 90S) PREVIOUSLY LOCATED 
NEAR 9.5S 103.3E IS NOW LOCATED NEAR 10.8S 102.9E, APPROXIMATELY 168 
NM WEST OF CHRISTMAS ISLAND. ANIMATED MULTISPECTRAL SATELLITE 
IMAGERY AND A 030949Z SSMIS F-16 91GHZ MICROWAVE IMAGE DEPICT 
FRAGMENTED DEEP CONVECTION IN POTENTIAL BANDING FEATURES WRAPPING 
AROUND A SLIGHTLY ELONGATED, FULLY OBSCURED LOW LEVEL CIRCULATION 
(LLC). A 030306Z METOP-C ASCAT PASS REVEALS A SYMMETRIC, WEAK LLC 
SURROUNDED BY 5 TO 15 KNOTS OF WIND. 90S IS CURRENTLY IN A FAVORABLE 
ENVIRONMENT WITH WARM (30 CELSIUS) SEA SURFACE TEMPERATURES AND 
EXCELLENT POLEWARD OUTFLOW BEING SLIGHTLY OFFSET BY MODERATE (15 TO 
20 KNOT) VERTICAL WIND SHEAR. GLOBAL MODELS ARE IN GOOD AGREEMENT 
THAT 90S WILL CONTINUE TO TRACK GENERALLY SOUTHEASTWARD, REMAINING 
ELONGATED WHILE INTENSIFYING, POTENTIALLY REACHING WARNING THRESHOLD 
IN 2 TO 4 DAYS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 
TO 25 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1003 
MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL 
CYCLONE WITHIN THE NEXT 24 HOURS IS UPGRADED TO MEDIUM.
      (3) NO OTHER SUSPECT AREAS.
   C. SUBTROPICAL SYSTEM SUMMARY: NONE.
3. JUSTIFICATION FOR REISSUE: UPGRADED AREA IN PARA 2.B.(1) TO A 
HIGH AND AREA IN PARA 2.B.(2) TO MEDIUM. AREA IN PARA 1.B.(1) HAS 
DISSIPATED.//
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