ABIO10 PGTW 041800
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE INDIAN
/OCEAN/041800Z-051800ZFEB2021//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/041351ZFEB2021//
AMPN/REF A IS A TROPICAL CYCLONE WARNING.//
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:
      (1) AT 04FEB21 1200Z, TROPICAL CYCLONE 18S (EIGHTEEN) WAS 
LOCATED NEAR 24.6S 113.4E, APPROXIMATELY 143 NM SOUTH-SOUTHWEST OF 
LEARMONTH, AUSTRALIA, AND HAD TRACKED SOUTHWESTWARD AT 03 KNOTS OVER 
THE PAST SIX HOURS. MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED 
AT 35 KNOTS GUSTING TO 45 KNOTS. SEE REF A (WTXS31 PGTW 041500) FOR 
FURTHER DETAILS.
      (2) NO OTHER TROPICAL CYCLONES.
   B. TROPICAL DISTURBANCE SUMMARY:
      (1) AN AREA OF CONVECTION (INVEST 90S) HAS PERSISTED NEAR 
11.2S 81.3E, APPROXIMATELY 900 NM WEST OF COCOS ISLAND. ANIMATED 
ENHANCED INFRARED IMAGERY (EIR) AND A 041345Z SSMIS 91 GHZ SATELLITE 
IMAGE DEPICTS A DISORGANIZED LOW LEVEL CIRCULATION (LLC)WITH FLARING 
CONVECTION ALOFT. UPPER LEVEL ANALYSIS INDICATES 90S IS IN A 
MODERATELY FAVORABLE ENVIRONMENT FOR DEVELOPMENT WITH GOOD 
DIVERGENCE ALOFT AND WARM (29-30C) SEA SURFACE TEMPERATURES (SST) 
ONLY TO BE OFFSET BY STRONG (25-30 KTS) OF VERTICAL WIND SHEAR. 
GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 90S WILL CONTINUE TO TRACK 
EASTWARD OVER THE NEXT 24 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE 
ESTIMATED AT 15 TO 20 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 LOW.
      (2) NO OTHER SUSPECT AREAS.
   C. SUBTROPICAL SYSTEM SUMMARY: NONE.//
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