WPAC: KOINU - Post-Tropical

[Hayabusa]

93W INVEST 230927 0000 14.2N 144.4E WPAC 15 0

[Hayabusa]

eps 18z

[Hayabusa]

Now low

ABPW10 PGTW 270300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND SOUTH
PACIFIC OCEANS REISSUED/270300Z-270600ZSEP2023//
RMKS/
1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY:
(1) AN AREA OF CONVECTION (INVEST 93W) HAS PERSISTED NEAR 13.8N
144.2E, APPROXIMATELY 36 NM NORTHWEST OF ANDERSON AFB, GUAM. ANIMATED
MULTISPECTRAL SATELLITE (MSI) DEPICTS AN ELONGATED SOUTHWEST TO
NORTHEAST ORIENTED TROUGH DRAPED ACROSS THE SOUTHERN MARIANAS THAT IS
SLOWLY CONSOLIDATING WITH PERSISTENT FLARING CONVECTION OVER A BROAD LOW
LEVEL CIRCULATION CENTER (LLCC). 93W IS LOCATED WITHIN THE EASTERN SIDE
OF A GYRE ENCOMPASSING THE PHILIPPINE SEA. ENVIRONMENTAL ANALYSIS SHOWS
FAVORABLE FACTORS FOR FURTHER DEVELOPMENT WITH FAVORABLE (10-15KT) VWS,
VERY WARM (30-31C) SST, AND MODERATE UPPER-LEVEL OUTFLOW THAT IS
EXPECTED TO IMPROVE IN ABOUT 3 DAYS. GLOBAL MODELS AGREE ON 93W RIDING
NORTHWESTWARDD ALONG THE EASTERN EDGE OF THE GYRE AND SLOWLY
CONSOLIDATING AND INTENSIFYING OVER THE NEXT FEW DAYS. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 13 TO 18 KNOTS. MINIMUM SEA LEVEL
PRESSURE IS ESTIMATED TO BE NEAR 1004 MB. THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS
IS LOW.

[Hayabusa]

GFS recurves, while Euro travels north then a westward track towards Luzon strait...

[Hayabusa]

00z

[Hayabusa]

eps 06z

[Hayabusa]

12z, Euro still same track towards Luzon strait

[Hayabusa]

eps 06z

[Hayabusa]

WWJP27 RJTD 281800
WARNING AND SUMMARY 281800.
WARNING VALID 291800.
WARNING IS UPDATED EVERY 6 HOURS.
TROPICAL DEPRESSION 1004 HPA AT 16N 137E WEST SLOWLY.

Euro 12z has turned stronger, while not developing the 160E'r anymore

[Hayabusa]

Eps 18z

[Hayabusa]

tcfa

WTPN21 PGTW 290230
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 93W)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
120 NM EITHER SIDE OF A LINE FROM 15.8N 136.5E TO 16.5N 131.1E
WITHIN THE NEXT 06 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 18 TO 23 KNOTS. METSAT
IMAGERY AT 290000Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 15.8N 136.2E. THE SYSTEM IS MOVING WESTWARD AT 10 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 93) PREVIOUSLY LOCATED NEAR
15.4N 141.5E IS NOW LOCATED NEAR 15.8N 136.2E, APPROXIMATELY 877 NM EAST
OF MANILA, PHILIPPINES. ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND A
282147Z SSMIS 91GHZ SATELLITE IMAGE SHOW MID-LEVEL TURNING AND SHALLOW
RAIN BANDS WRAPPING INTO A WELL-DEFINED, PARTLY EXPOSED LOW-LEVEL
CIRCULATION CENTER. ENVIRONMENTAL ANALYSIS REVEALS THE INVEST IS IN A
FAVORABLE ENVIRONMENT FOR DEVELOPMENT DEFINED BY ROBUST EQUATORWARD
OUTFLOW, FAVORABLE (10-15 KT) VERTICAL WIND SHEAR, AND VERY WARM (30-31C)
SEA SURFACE TEMPERATURES. THE INVEST IS ALSO IN AN AREA WITH A RELATIVELY
PRONOUNCED 850 MB VORTICITY SIGNATURE. GLOBAL MODELS ARE IN GENERAL
AGREEMENT THAT 93W WILL TRACK WEST TO WEST-NORTHWESTWARD AND INTENSIFY AS
IT APPROACHES NORTHERN LUZON. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 18 TO 23 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO
BE NEAR 1005 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
300230Z.
//
NNNN

[Hayabusa]

Jma

Issued at 2023/09/29 07:30 UTC
Analysis at 09/29 06 UTC
Grade TD
Scale -
Intensity -
Center position N15°10′ (15.2°)
E135°05′ (135.1°)
Direction and speed of movement W 10 km/h (6 kt)
Central pressure 1002 hPa
Maximum sustained wind speed near center 15 m/s (30 kt)
Maximum wind gust speed 23 m/s (45 kt)
Forecast for 09/30 06 UTC
Grade TS
Intensity -
Center position of probability circle N16°25′ (16.4°)
E132°10′ (132.2°)
Direction and speed of movement WNW 15 km/h (8 kt)
Central pressure 998 hPa
Maximum sustained wind speed near center 18 m/s (35 kt)
Maximum wind gust speed 25 m/s (50 kt)
Radius of probability circle 130 km (70 NM)
Forecast for 10/01 06 UTC
Grade TS
Intensity -
Center position of probability circle N18°30′ (18.5°)
E130°40′ (130.7°)
Direction and speed of movement NNW 10 km/h (6 kt)
Central pressure 996 hPa
Maximum sustained wind speed near center 18 m/s (35 kt)
Maximum wind gust speed 25 m/s (50 kt)
Radius of probability circle 200 km (110 NM)
Forecast for 10/02 06 UTC
Grade TS
Intensity -
Center position of probability circle N20°20′ (20.3°)
E129°30′ (129.5°)
Direction and speed of movement NNW Slow
Central pressure 994 hPa
Maximum sustained wind speed near center 20 m/s (40 kt)
Maximum wind gust speed 30 m/s (60 kt)
Radius of probability circle 260 km (140 NM)
Forecast for 10/03 06 UTC
Grade TS
Intensity -
Center position of probability circle N21°55′ (21.9°)
E127°40′ (127.7°)
Direction and speed of movement NW 10 km/h (6 kt)
Central pressure 990 hPa
Maximum sustained wind speed near center 23 m/s (45 kt)
Maximum wind gust speed 35 m/s (65 kt)
Radius of probability circle 330 km (180 NM)
Forecast for 10/04 06 UTC
Grade STS
Intensity -
Center position of probability circle N22°20′ (22.3°)
E123°50′ (123.8°)
Direction and speed of movement W 15 km/h (9 kt)
Central pressure 980 hPa
Maximum sustained wind speed near center 30 m/s (55 kt)
Maximum wind gust speed 40 m/s (80 kt)
Radius of probability circle 440 km (240 NM)
Radius of storm warning area 600 km (330 NM)

[Hayabusa]

00z

[doomhaMwx]

Unsurprisingly, GFS has caved into the Euro with regard to development and track.

[doomhaMwx]

PAGASA's first forecast has it as a typhoon near Batanes by mid-next week.

[Hayabusa]

14W FOURTEEN 230929 1200 15.5N 134.2E WPAC 25 1004

[Hayabusa]

EPS 06Z

[xtyphooncyclonex]

The sudden aggressiveness from the models right after development and its rather quick consolidation to a rather slow movement. I'm kinda getting Saola 2.0 vibes from this one.

[Hayabusa]

[cycloneye]

 https://twitter.com/squirtleinhk/status/1707860590499111178