WPAC: 91W - Tropical Depression

[Hayabusa]

91W INVEST 250916 1800 22.3N 168.0E WPAC 15 1013

[Hayabusa]

Euro AI has been showing this becoming a significant TC but is just a fish storm...

[Hayabusa]

Now low

ABPW10 PGTW 170200
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND SOUTH
PACIFIC OCEANS REISSUED/170200Z-170600ZSEP2025//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/161951ZSEP2025//
AMPN/REF A IS A TROPICAL CYCLONE WARNING.//
RMKS/
1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA):
A. TROPICAL CYCLONE SUMMARY:
(1) AT 16SEP25 1800Z, TROPICAL STORM 23W (TWENTYTHREE) WAS
LOCATED NEAR 16.1N 122.2E, APPROXIMATELY 114 NM NORTHEAST OF MANILA,
PHILIPPINES, AND HAD TRACKED NORTHWESTWARD AT 04 KNOTS OVER THE PAST
SIX HOURS. MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED AT 45 KNOTS
GUSTING TO 55 KNOTS. SEE REF A (WTPN31 PGTW 162100) FOR FURTHER
DETAILS.
(2) NO OTHER TROPICAL CYCLONES.
B. TROPICAL DISTURBANCE SUMMARY:
(1) THE AREA OF CONVECTION (INVEST 90W) PREVIOUSLY LOCATED NEAR
15.0N 137.5E IS NOW LOCATED NEAR 13.6N 136.6E, APPROXIMATELY 225 NM
NORTH-NORTHWEST OF YAP. ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND
A RECENT 162205Z F16 SSMIS MICROWAVE IMAGE DEPICT A CONSOLIDATING,
OBSCURED LOW LEVEL CIRCULATION (LLC) WITH BROAD CONVECTIVE BANDING
AND PERSISTENT, FLARING CONVECTION. A RECENT 162051Z SCATTEROMETER
PASS REVEALS 15-20 KNOTS THROUGHOUT THE CIRCULATION.ENVIRONMENTAL
ANALYSIS REVEALS FAVORABLE CONDITIONS FOR DEVELOPMENT WITH LOW
VERTICAL WIND SHEAR OF 5-10 KNOTS, MODERATE DUAL-CHANNEL UPPER-LEVEL
OUTFLOW, AND WARM SEA SURFACE TEMPERATURES (SST) OF 30 TO 31 DEGREES
CELSIUS. GLOBAL MODELS AGREE ON GRADUAL CONSOLIDATION AND
INTENSIFICATION OF THE SYSTEM AS IT MOVES GENERALLY WEST-
NORTHWESTWARD. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 18 TO
23 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1007 MB.
THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS UPGRADED TO MEDIUM.
(2) AN AREA OF CONVECTION (INVEST 91W) HAS PERSISTED NEAR 22.9N
167.1E, APPROXIMATELY 221 NM NORTH OF WAKE ISLAND. ANIMATED
MULTISPECTRAL SATELLITE IMAGERY DEPICTS A PARTIALLY OBSCURED, LOWER
LEVEL CIRCULATION (LLC) WITH FLARING CONVECTION, PRIMARILY IN THE
SOUTHERN SEMICIRCLE. A RECENT 162209Z ASCAT PASS SHOWS A SHARP TROUGH
WITH A SWATH OF WINDS OF 15-20 KNOTS ALONG THE SOUTHEAST OF THE
TROUGH. ENVIRONMENTAL ANALYSIS REVEALS FAVORABLE CONDITIONS FOR
DEVELOPMENT WITH LOW VERTICAL WIND SHEAR (VWS) OF 10-15 KNOTS, GOOD
POLEWARD UPPER-LEVEL OUTFLOW, AND WARM SEA SURFACE TEMPERATURES (SST)
OF 29-30 C. GLOBAL MODELS AGREE ON A GENERAL WEST-NORTHWESTWARD
TRACK, BUT ARE SPLIT ON DEVELOPMENT, WITH ENSEMBLES SHOWING MORE
INTENSIFICATION THAN THE DETERMINISTIC ECMWF AND GFS. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 13 TO 18 KNOTS. MINIMUM SEA
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1013 MB. THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS IS LOW.
(3) NO OTHER SUSPECT AREAS.
C. SUBTROPICAL SYSTEM SUMMARY: NONE.
2. SOUTH PACIFIC AREA (WEST COAST OF SOUTH AMERICA TO 135 EAST):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY: NONE.
C. SUBTROPICAL SYSTEM SUMMARY: NONE.
3. JUSTIFICATION FOR REISSUE: UPGRADED
AREA IN PARA 1.B.(1) TO MEDIUM AND ADDED LOW AREA IN PARA. 1.B.(2).//
NNNN

[Hayabusa]

JMA 12Z TD

WWJP27 RJTD 171200
WARNING AND SUMMARY 171200.
WARNING VALID 181200.
WARNING IS UPDATED EVERY 6 HOURS.
TROPICAL DEPRESSION 1012 HPA AT 23N 166E WEST SLOWLY.

[Hayabusa]

Euro 00z makes an anticyclonic loop instead of recurving early

[Hayabusa]

Latest Euro 12z makes this more intense than 90W

[Hayabusa]

Wow, it reintensifies and tracks westward after doing a loop in the later taus

[Hayabusa]

12z uncertainty is widespread

[Hayabusa]

JMA 18Z

TD c
Issued at 2025/09/17 19:30 UTC
Analysis at 09/17 18 UTC
Grade TD
Scale -
Intensity -
Center position N22°20′ (22.3°)
E165°35′ (165.6°)
Direction and speed of movement W Slow
Central pressure 1010 hPa
Maximum sustained wind speed near center 15 m/s (30 kt)
Maximum wind gust speed 23 m/s (45 kt)

[Hayabusa]

Up to medium

ABPW10 PGTW 172000
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND SOUTH
PACIFIC OCEANS REISSUED/172000Z-180600ZSEP2025//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/171351ZSEP2025//
AMPN/REF A IS A TROPICAL CYCLONE WARNING.//
RMKS/
1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA):
A. TROPICAL CYCLONE SUMMARY:
(1) AT 17SEP25 1200Z, TROPICAL DEPRESSION 23W (TWENTYTHREE) WAS
LOCATED NEAR 18.6N 120.5E, APPROXIMATELY 242 NM NORTH OF MANILA,
PHILIPPINES, AND HAD TRACKED NORTHWESTWARD AT 10 KNOTS OVER THE PAST
SIX HOURS. MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED AT 25 KNOTS
GUSTING TO 35 KNOTS. SEE REF A (WTPN31 PGTW 171500) FOR FURTHER
DETAILS.
(2) NO OTHER TROPICAL CYCLONES.
B. TROPICAL DISTURBANCE SUMMARY:
(1) THE AREA OF CONVECTION (INVEST 90W) PREVIOUSLY LOCATED NEAR
13.6N 136.6E IS NOW LOCATED NEAR 15.7N 134.3E, APPROXIMATELY 329 NM
NORTH-NORTHWEST OF YAP. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
(EIR) DEPICTS A POORLY ORGANIZED BROAD CIRCULATION CENTER WITH WEAK
CENTRAL CONVECTION. ENVIRONMENTAL ANALYSIS FOR THE AREA INDICATES
FAVORABLE CONDITIONS FOR DEVELOPMENT WITH LOW VERTICAL WIND SHEAR (10-
15 KTS), WARM SEA SURFACE TEMPERATURES (30-31 C) AND GOOD EQUATORWARD
OUTFLOW ALOFT. GLOBAL DETERMINISTIC MODELS HAVE 90W TRACKING NORTH
NORTHWEST WITH GFS BEING SLIGHTLY MORE INTENSE THAN ECMWF. GLOBAL
ENSEMBLE GUIDANCE HAS 90W TRACKING NORTH NORTHWEST, WHILE ECENS
PROJECTING HIGHER INTENSITY THAN GEFS. MAXIMUM SUSTAINED SURFACE
WINDS ARE ESTIMATED AT 18 TO 23 KNOTS. MINIMUM SEA LEVEL PRESSURE IS
ESTIMATED TO BE NEAR 1008 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS MEDIUM.
(2) THE AREA OF CONVECTION (INVEST 91W) PREVIOUSLY LOCATED NEAR
22.9N 167.1E IS NOW LOCATED NEAR 23.4N 165.9E, APPROXIMATELY 350 NM
NORTH OF WAKE. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY (EIR)
DEPICTS PERSISTENT DEEP CONVECTION WITHIN THE TROPICAL WAVE AS IT
BEGINS TO SLOWLY CONSOLIDATE A LOW LEVEL CIRCULATION CENTER (LLCC). A
171013Z ASCAT IMAGE SHOWS 15-20 KNOT WINDS COMING DIRECTLY FROM THE
SOUTH. ENVIRONMENTAL ANALYSIS FOR THE AREA INDICATES FAVORABLE
CONDITIONS FOR DEVELOPMENT WITH LOW VERTICAL WIND SHEAR (10-15 KTS),
WITH WARM SEA SURFACE TEMPERATURES (30-31 C) AND GOOD EQUATORWARD
OUTFLOW ALOFT. GLOBAL DETERMINISTIC MODELS ARE IN FAIR AGREEMENT THAT
91W WILL CONTINUE TO TRACK WEST WITH ECMWF BEING MORE INTENSE THAN THE
OTHER MODELS. GLOBAL ENSEMBLE GUIDANCE HAS 91W TRACKING WEST WITH
ECMWF HAVING A HIGHER INTENSITY GUIDANCE THAN GEFS. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 18 TO 23 KNOTS. MINIMUM SEA LEVEL
PRESSURE IS ESTIMATED TO BE NEAR 1009 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.
2. SOUTH PACIFIC AREA (WEST COAST OF SOUTH AMERICA TO 135 EAST):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY: NONE.
C. SUBTROPICAL SYSTEM SUMMARY: NONE.
3. JUSTIFICATION FOR REISSUE: UPGRADED AREA IN PARA 1.B.(2) TO
MEDIUM.//
NNNN

[cycloneye]

TCFA.

WTPN21 PGTW 180200
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
160 NM EITHER SIDE OF A LINE FROM 23.5N 164.3E TO 24.7N 156.0E
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 23 TO 28 KNOTS. METSAT
IMAGERY AT 180000Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 23.5N 164.3E. THE SYSTEM IS MOVING WESTWARD AT 12 KNOTS.
2. REMARKS:THE AREA OF CONVECTION (INVEST 91W) PREVIOUSLY LOCATED 22.9N
167.1E IS NOW LOCATED 23.5N 164.3E APPROXIMATELY 282 NM NORTH NORTHWEST
OF WAKE.ANIMATED ENHANCED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS
A CONSOLIDATING LOW LEVEL CIRCULATION CENTER (LLCC), WITH PERSISTENT
DEEP CONVECTION FROM THE SOUTH SOUTHEAST. A 172240Z ASCAT IMAGE REVEALS
20-25 KNOT WINDS TO THE EAST AND NORTHEAST OF 91W. ENVIRONMENTAL
ANALYSIS FOR THE AREA INDICATES FAVORABLE CONDITIONS FOR DEVELOPMENT
WITH LOW VERTICAL WIND SHEAR (10-15 KTS), WITH WARM SEA SURFACE
TEMPERATURES (30-31C) AND GOOD EQUATORWARD OUTFLOW ALOFT. GLOBAL
DETERMINISTIC MODELS ARE NOT IN AGREEMENT WITH ECMWF SHOWING SUPPORT FOR
A HIGHER INTENSITY OVER THE NEXT 48 HOURS WHILE NO OTHER DETERMINISTIC
MODELS SHOW SUPPORT. GLOBAL ENSEMBLE GUIDANCE HAS 91W ONLY PICKING UP ON
ECENS WITH A HIGHER INTENSITY OVER GEFS. MAXIMUM SUSTAINED SURFACE WINDS
ARE ESTIMATED AT 23 TO 28 KNOTS.MINIMUM SEA LEVEL PRESSURE IS ESTIMATED
TO BE NEAR 1001 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

[cycloneye]