ABIO10 PGTW 311800
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE INDIAN 
OCEAN/311800ZDEC2025-011800ZJAN2026//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/311351ZDEC2025//
REF/B/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/301951ZDEC2025//
REF/C/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/311351ZDEC2025//
NARR/REF A IS A TROPICAL CYCLONE WARNING. REF B IS A TROPICAL CYCLONE 
FINAL WARNING. REF C 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:
      (1) AT 31DEC25 1200Z, TROPICAL CYCLONE 09S (GRANT) WAS LOCATED 
NEAR 15.7S 69.6E, APPROXIMATELY 543 NM SOUTH-SOUTHWEST OF DIEGO 
GARCIA, AND HAD TRACKED WESTWARD AT 23 KNOTS OVER THE PAST SIX HOURS. 
MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED AT 100 KNOTS GUSTING 
TO 125 KNOTS. SEE REF A (WTXS32 PGTW 311500) FOR FURTHER DETAILS.
      (2) AT 30DEC25 1800Z, TROPICAL CYCLONE 10S (HAYLEY) WAS LOCATED 
NEAR 16.8S 124.3E, APPROXIMATELY 137 NM EAST-NORTHEAST OF BROOME, 
AUSTRALIA, AND HAD TRACKED EASTWARD AT 11 KNOTS OVER THE PAST SIX 
HOURS. MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED AT 55 KNOTS 
GUSTING TO 70 KNOTS. SEE REF B (WTXS31 PGTW 302100) FOR THE FINAL 
WARNING ON THIS SYSTEM.
      (3) NO OTHER TROPICAL CYCLONES.
   B. TROPICAL DISTURBANCE SUMMARY:
      (1) THE AREA OF CONVECTION (INVEST 90S) PREVIOUSLY LOCATED NEAR 
10.5S 105.4E IS NOW LOCATED NEAR 10.5S 105.7E, APPROXIMATELY 5 NM 
NORTH OF CHRISTMAS ISLAND. ANIMATED ENHANCED INFRARED SATELLITE 
IMAGERY (EIR) DEPICTS A FULLY OBSCURED, LOW LEVEL CIRCULATION (LLC) 
WITH PERSISTENT CONVECTION BUILDING OVER THE CENTER. ENVIRONMENTAL 
ANALYSIS REVEALS A MARGINALLY FAVORABLE ENVIRONMENT FOR DEVELOPMENT 
WITH LOW TO MODERATE VERTICAL WIND SHEAR (VWS) OF 15-20 KNOTS, GOOD 
POLEWARD UPPER-LEVEL OUTFLOW, AND WARM SEA SURFACE TEMPERATURES (SST) 
OF 28-29 C. GLOBAL MODELS ARE IN GOOD AGREEMENT ON FURTHER 
DEVELOPMENT AND A SOUTHEASTWARD TRACK OVER THE NEXT 24 HOURS. MAXIMUM 
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 28 TO 33 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 REMAINS HIGH. SEE REF C (WTXS21 PGTW 311330) FOR FURTHER 
DETAILS.
      (2) NO OTHER SUSPECT AREAS.
   C. SUBTROPICAL SYSTEM SUMMARY: NONE.//
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