SIO: INVEST 09S

[Subtrop]

97S INVEST 250106 0000 9.4S 115.2E SHEM 15 1009

[StormWeather]

TCFA on Invest 97S (Tropical Low 09U)

WTXS21 PGTW 100200
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 97S)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
A 120 NM RADIUS OF 17.9S 102.8E WITHIN THE NEXT 12 TO 24 HOURS.
AVAILABLE DATA DOES NOT JUSTIFY ISSUANCE OF NUMBERED TROPICAL
CYCLONE WARNINGS AT THIS TIME. WINDS IN THE AREA ARE ESTIMATED TO
BE 28 TO 33 KNOTS. METSAT IMAGERY AT 102000Z INDICATES THAT A
CIRCULATION CENTER IS LOCATED NEAR 17.4S 103.5E. THE SYSTEM IS
MOVING SOUTHWARD AT 07 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 97S) PREVIOUSLY LOCATED NEAR
16.7S 103.6E IS NOW LOCATED NEAR 17.4S 103.5E, APPROXIMATELY 495 NM
SOUTHEAST OF THE COCOS ISLANDS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
DEPICTS A QUICKLY CONSOLIDATING LLCC WITH DEEP PERSISTENT CONVECTION
BUILDING OVER THE CENTER. A 092318Z SSMIS F-17 91 GHZ DEPICTS LOW LEVEL
CLOUDS TIGHTLY WRAPPING INTO THE SYSTEM CENTER. ENVIRONMENTAL ANALYSIS
REVEALS FAVORABLE CONDITIONS FOR DEVELOPMENT WITH LOW VERTICAL WIND SHEAR
(10-15 KNOTS), WARM (29-30C) SEA SURFACE TEMPERATURES, AND MODERATE RADIAL
OUTFLOW ALOFT. GLOBAL ENSEMBLES ARE MORE AGGRESSIVE OVERALL WHILE
DETERMINISTIC MODELS SHOW A SMALL WINDOW OF POTENTIAL GALE FORCE
INTENSITY. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 28 TO 33
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 998 MB. THE
POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
110200Z.//
NNNN

[StormWeather]

TCFA on Invest 97S (Tropical Low 09U)

WTXS21 PGTW 100200
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 97S)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
A 120 NM RADIUS OF 17.9S 102.8E WITHIN THE NEXT 12 TO 24 HOURS.
AVAILABLE DATA DOES NOT JUSTIFY ISSUANCE OF NUMBERED TROPICAL
CYCLONE WARNINGS AT THIS TIME. WINDS IN THE AREA ARE ESTIMATED TO
BE 28 TO 33 KNOTS. METSAT IMAGERY AT 102000Z INDICATES THAT A
CIRCULATION CENTER IS LOCATED NEAR 17.4S 103.5E. THE SYSTEM IS
MOVING SOUTHWARD AT 07 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 97S) PREVIOUSLY LOCATED NEAR
16.7S 103.6E IS NOW LOCATED NEAR 17.4S 103.5E, APPROXIMATELY 495 NM
SOUTHEAST OF THE COCOS ISLANDS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
DEPICTS A QUICKLY CONSOLIDATING LLCC WITH DEEP PERSISTENT CONVECTION
BUILDING OVER THE CENTER. A 092318Z SSMIS F-17 91 GHZ DEPICTS LOW LEVEL
CLOUDS TIGHTLY WRAPPING INTO THE SYSTEM CENTER. ENVIRONMENTAL ANALYSIS
REVEALS FAVORABLE CONDITIONS FOR DEVELOPMENT WITH LOW VERTICAL WIND SHEAR
(10-15 KNOTS), WARM (29-30C) SEA SURFACE TEMPERATURES, AND MODERATE RADIAL
OUTFLOW ALOFT. GLOBAL ENSEMBLES ARE MORE AGGRESSIVE OVERALL WHILE
DETERMINISTIC MODELS SHOW A SMALL WINDOW OF POTENTIAL GALE FORCE
INTENSITY. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 28 TO 33
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 998 MB. THE
POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
110200Z.//
NNNN

[cycloneye]

THE AREA OF CONVECTION (INVEST 97S) PREVIOUSLY LOCATED NEAR
17.4S 103.5E IS NOW LOCATED NEAR 17.7S 103.3E, APPROXIMATELY 499 NM
NORTHWEST OF THE COCOS ISLANDS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY DEPICTS A LOW LEVEL CIRCULATION CENTER THAT HAS BECOME EXPOSED
AND SEPARATED FROM ANY DEEP CONVECTION. ENVIRONMENTAL ANALYSIS REVEALS
MARGINALLY FAVORABLE CONDITIONS FOR DEVELOPMENT WITH LOW VERTICAL WIND
SHEAR (10-15 KNOTS), WARM (29-30C) SEA SURFACE TEMPERATURES, OFFSET BY
WEAK OUTFLOW ALOFT. THERE HAS BEEN AN INCREASE IN DRY AIR ENTRAINMENT
INTO 97S CAUSING THE SYSTEM TO WEAKEN AND THE LIKELIHOOD OF DEVELOPMENT
TO DECREASING. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 23 TO 38
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 DOWNGRADED TO LOW.

[Subtrop]

JTWC TRANSITIONED TO SH092025

NINE, SH, S, , , , , 09, 2025, TD, S, 2025010712, 2025011518, , , , , 5, , 2, SH092025

[StormWeather]

JTWC TRANSITIONED TO SH092025

NINE, SH, S, , , , , 09, 2025, TD, S, 2025010712, 2025011518, , , , , 5, , 2, SH092025

I’m sorry…. WHAT!?

[StormWeather]

JTWC TRANSITIONED TO SH092025

NINE, SH, S, , , , , 09, 2025, TD, S, 2025010712, 2025011518, , , , , 5, , 2, SH092025

With the recent designation of 10S this appears to be valid. Might have to stay tuned for reanalysis.

[StormWeather]

According to the Wikipedia article on the 2024-25 Australian Region Tropical Cyclone Season, BOM retroactively upgraded this system to Category 1 on the Australian Scale, meaning the AR now has 8 tropical cyclones, and this system is now recognized by both the JTWC and BOM as a tropical cyclone.