Indian Ocean Tropical Cyclone Tracking

Tropical Cyclone COURTNEY Tracking

1. TROPICAL CYCLONE 27S (COURTNEY) WARNING NR 010    
   01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   270600Z --- NEAR 16.8S 100.0E
     MOVEMENT PAST SIX HOURS - 275 DEGREES AT 10 KTS
     POSITION ACCURATE TO WITHIN 060 NM
     POSITION BASED ON CENTER LOCATED BY SATELLITE
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT
                            030 NM SOUTHEAST QUADRANT
                            035 NM SOUTHWEST QUADRANT
                            020 NM NORTHWEST QUADRANT
   RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT
                            045 NM SOUTHEAST QUADRANT
                            050 NM SOUTHWEST QUADRANT
                            040 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
                            080 NM SOUTHEAST QUADRANT
                            095 NM SOUTHWEST QUADRANT
                            080 NM NORTHWEST QUADRANT
   REPEAT POSIT: 16.8S 100.0E

ABIO10 PGTW 270500 COR
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE INDIAN OCEAN 
REISSUED CORRECTED/270500Z-280500ZMAR2025//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/261951ZMAR2025//
REF/B/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/270721ZMAR2025//
NARR/REF A IS A TROPICAL CYCLONE WARNING. REF B 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 26MAR25 1800Z, TROPICAL CYCLONE 27S (COURTNEY) WAS 
LOCATED NEAR 17.4S 102.2E, APPROXIMATELY 438 NM SOUTHEAST OF THE 
COCOS ISLANDS, AND HAD TRACKED WESTWARD AT 10 KNOTS OVER THE PAST SIX 
HOURS. MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED AT 70 KNOTS 
GUSTING TO 85 KNOTS. SEE REF A (WTXS31 PGTW 262100) FOR FURTHER 
DETAILS.
      (2) NO OTHER TROPICAL CYCLONES.
   B. TROPICAL DISTURBANCE SUMMARY:
      (1) THE AREA OF CONVECTION (INVEST 93S) PREVIOUSLY LOCATED NEAR 
14.9S 121.0E IS NOW LOCATED NEAR 13.8S 121.4E, APPROXIMATELY 252 NM 
NORTH OF BROOME, AUSTRALIA. ANIMATED MULTISPECTRAL SATELLITE IMAGERY 
(MSI) DEPICTS EXPOSED LOW LEVEL CLOUD LINES WRAPPING INTO A WELL-
DEFINED LOW LEVEL CIRCULATION CENTER (LLCC), WITH VERY INTENSE, DEEP 
PERSISTENT CONVECTION SHEARED OFF TO THE WEST SIDE. A 270142Z 
ASCAT-C BULLSEYE PASS SHOWS A WELL-DEFINED CENTER, WITH A SWATH OF 30 
KNOT WINDS OVER THE WESTERN SEMICIRCLE. ENVIRONMENTAL ANALYSIS 
REVEALS A MARGINALLY FAVORABLE ENVIRONMENT FOR DEVELOPMENT WITH 
MODERATE TO HIGH VERTICAL WIND SHEAR (VWS) OF 20-25 KNOTS, OFFSET BY 
WESTWARD UPPER-LEVEL OUTFLOW AND WARM SEA SURFACE TEMPERATURES (SST) 
OF 30-31 C. OVER THE COURSE OF 48 HOURS, BOTH DETERMINISTIC AND 
ENSEMBLE MODELS AGREE ON THE SYSTEM'S TRACK, INITIALLY MOVING THE 
SYSTEM NORTHEAST BEFORE SHIFTING TO A SOUTHEASTWARD TRACK TOWARD THE 
NORTHWESTERN COAST OF AUSTRALIA. CONFIDENCE IN DEVELOPMENT IS SPLIT, 
WITH MOST MODEL MEMBERS REACHING TROPICAL STORM STRENGTH. WHILE ECMWF 
AND NAVGEM PREDICT A WEAKER SYSTEM (25-30 KNOTS), THE GFS MODEL 
FORECASTS A STRONGER SYSTEM, POTENTIALLY REACHING WARNING CRITERIA BY 
TAU 18. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 25 TO 30 
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 997 MB. THE 
POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE 
WITHIN THE NEXT 24 HOURS IS UPGRADED TO HIGH. SEE REF B (WTXS21 PGTW 
270500) FOR FURTHER DETAILS.
      (2) NO OTHER SUSPECT AREAS.
   C. SUBTROPICAL SYSTEM SUMMARY: NONE.
3. JUSTIFICATION FOR REISSUE: UPGRADED AREA IN PARA. 2.B.(1) TO HIGH.
4. JUSTIFICATION FOR CORRECTION: CORRECTED DIRECTION IN REFERENCE TO 
THE COAST OF AUSTRALIA IN PARA. 2.B.(1). UPDATED REF B DTG TO REFLECT 
CORRECTED TCFA MESSAGE.//
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