WPAC: HAIKUI - Post-Tropical

[Subtrop]

93W INVEST 230825 0000 14.5N 141.1E WPAC 15 0

[Hayabusa]

Models make this a large TC, which may have an impact on Saola's future track
Eps 00z

[Sciencerocks]

[Hayabusa]

Now low

ABPW10 PGTW 251800
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND SOUTH
PACIFIC OCEANS REISSUED/251800Z-260600ZAUG2023//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/251351ZAUG2023//
REF/B/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/251352ZAUG2023//
NARR/REFS A AND B ARE TROPICAL CYCLONE WARNINGS.//
RMKS/
1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA):
A. TROPICAL CYCLONE SUMMARY:
(1) AT 25AUG23 1200Z, TYPHOON 09W (SAOLA) WAS LOCATED NEAR 19.4N
123.8E, APPROXIMATELY 480 NM SOUTH- SOUTHWEST OF KADENA AB, AND HAD
TRACKED SOUTH-SOUTHWESTWARD AT 04 KNOTS OVER THE PAST SIX HOURS.
MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED AT 90 KNOTS GUSTING TO
110 KNOTS. SEE REF B (WTPN32 PGTW 251500) FOR FURTHER DETAILS.
(2) AT 25AUG23 1200Z, TROPICAL STORM 08W (DAMREY) WAS LOCATED
NEAR 21.5N 155.8E, APPROXIMATELY 190 NM SOUTH-SOUTHEAST OF MINAMI TORI
SHIMA, AND HAD TRACKED NORTHWARD AT 14 KNOTS OVER THE PAST SIX HOURS.
MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED AT 45 KNOTS GUSTING TO
55 KNOTS. SEE REF A (WTPN31 PGTW 251500) FOR FURTHER DETAILS.
(3) NO OTHER TROPICAL CYCLONES.
B. TROPICAL DISTURBANCE SUMMARY:
(1) AN AREA OF CONVECTION (INVEST 93W) HAS PERSISTED NEAR 14.8N
142.0E, APPROXIMATELY 180 NM WEST-NORTHWEST OF GUAM. ANIMATED ENHANCED
INFRARED SATELLITE IMAGERY AND A 251345Z GMI 89 GHZ MICROWAVE PASS
DEPICT A BROAD AND HIGHLY DISORGANIZED LOW LEVEL CIRCULATION WITH
INTENSE CONVECTIVE BURSTS ASSOCIATED WITH STRONG (20-25 KTS),
CONVERGENT MONSOONAL WESTERLIES. ENVIRONMENTAL ANALYSIS REVEALS
FAVORABLE CONDITIONS WITH A POINT SOURCE OVER THE SYSTEM WITH GOOD
OUTFLOW ALOFT. ADDITIONALLY, WARM (29-30 C) SST AND LOW (10-15 KTS)
VERTICAL WIND SHEAR ARE CONDUCIVE FOR DEVELOPMENT. GLOBAL MODELS
INDICATE 93W WILL TRACK SLOWLY EASTWARD WITH STEADY DEVELOPMENT OVER
THE NEXT 48 HOURS. THE SYSTEM WILL LIKELY STALL OVER OR TO THE WEST OF
THE NORTHERN MARIANAS WITH STRONG MONSOONAL FLOW PERSISTING OVER THE
REGION. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1000 MB. THE
POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN
THE NEXT 24 HOURS IS LOW.

[Hayabusa]

12z

[underthwx]

It looks as if 93W will not pose a threat to the Phillipines?

[Hayabusa]

Up to medium

ABPW10 PGTW 261800
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND SOUTH
PACIFIC OCEANS REISSUED/261800Z-270600ZAUG2023//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/261351ZAUG2023//
REF/B/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/261352ZAUG2023//
NARR/REFS B AND A ARE TROPICAL CYCLONE WARNINGS.//
RMKS/
1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA):
A. TROPICAL CYCLONE SUMMARY:
(1) AT 26AUG23 1200Z, TYPHOON 09W (SAOLA) WAS LOCATED NEAR 17.5N
123.1E, APPROXIMATELY 212 NM NORTHEAST OF MANILA, PHILIPPINES, AND HAD
TRACKED SOUTHWARD AT 05 KNOTS OVER THE PAST SIX HOURS. MAXIMUM
SUSTAINED SURFACE WINDS WERE ESTIMATED AT 110 KNOTS GUSTING TO 135
KNOTS. SEE REF B (WTPN32 PGTW 261500) FOR FURTHER DETAILS.
(2) AT 26AUG23 1200Z, TROPICAL STORM 08W (DAMREY) WAS LOCATED
NEAR 28.0N 151.1E, APPROXIMATELY 728 NM SOUTHEAST OF YOKOSUKA, JAPAN,
AND HAD TRACKED NORTHWESTWARD AT 25 KNOTS OVER THE PAST SIX HOURS.
MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED AT 50 KNOTS GUSTING TO
65 KNOTS. SEE REF A (WTPN31 PGTW 261500) FOR FURTHER DETAILS.
(3) NO OTHER TROPICAL CYCLONES.
B. TROPICAL DISTURBANCE SUMMARY:
(1) THE AREA OF CONVECTION (INVEST 93W) PREVIOUSLY LOCATED NEAR
15.5N 143.3E IS NOW LOCATED NEAR 16.3N 143.1E, APPROXIMATELY 198 NM
NORTH-NORTHWEST OF GUAM. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
AND A 261521Z ATMS 88.2 GHZ PASS DEPICT A SLOWLY CONSOLIDATING LOW
LEVEL CIRCULATION WITH A CURVED DEEP CONVECTIVE BAND IN THE NORTHERN
SEMICIRCLE. A 261220Z ASCAT-C PASS REVEALS AN ELONGATED, DEFINED
CIRCULATION WITH 15-20 KT WINDS TO THE WEST AND 20-25 KT, CONVERGENT,
MONSOONAL WESTERLIES DISPLACED TO THE SOUTH OF THE SYSTEM.
ENVIRONMENTAL ANALYSIS REVEALS FAVORABLE CONDITIONS FOR DEVELOPMENT
WITH WARM (29-30 C) SST, LOW (5-10 KTS) VERTICAL WIND SHEAR, AND
ROBUST POLEWARD OUTFLOW ALOFT. GLOBAL MODELS INDICATE 93W WILL TRACK
SLOWLY EASTWARD WITH STEADY DEVELOPMENT OVER THE NEXT 48 HOURS. THE
SYSTEM WILL LIKELY STALL OVER OR TO THE WEST OF THE NORTHERN MARIANAS
WITH STRONG MONSOONAL FLOW PERSISTING OVER THE REGION. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1000 MB. THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS
IS UPGRADED TO MEDIUM.

[Hayabusa]

It looks as if 93W will not pose a threat to the Phillipines?

Could be an indirect threat if it enhances the southwest monsoon bringing rains

[Hayabusa]

Euro 12z is a mess, doesn't develop it significantly compared to previous runs, and tracks further west enough that it does a binary interaction with a decaying Saola.

[Subtrop]

WTPQ52 RJTD 270000
RSMC TROPICAL CYCLONE ADVISORY
NAME TD
ANALYSIS
PSTN 270000UTC 17.3N 143.8E POOR
MOVE NE SLOWLY
PRES 1000HPA
MXWD 030KT
GUST 045KT
FORECAST
24HF 280000UTC 17.3N 143.5E 70NM 70%
MOVE ALMOST STATIONARY
PRES 998HPA
MXWD 035KT
GUST 050KT
48HF 290000UTC 17.5N 141.6E 110NM 70%
MOVE W SLOWLY
PRES 992HPA
MXWD 045KT
GUST 065KT
72HF 300000UTC 18.5N 138.0E 140NM 70%
MOVE WNW 09KT
PRES 990HPA
MXWD 050KT
GUST 070KT
96HF 310000UTC 19.5N 136.7E 180NM 70%
MOVE NW SLOWLY
PRES 990HPA
MXWD 050KT
GUST 070KT
120HF 010000UTC 21.9N 135.1E 240NM 70%
MOVE NNW 07KT
PRES 990HPA
MXWD 050KT
GUST 070KT =

[Subtrop]

WTPN21 PGTW 271500
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
130 NM EITHER SIDE OF A LINE FROM 18.6N 144.2E TO 20.9N 136.6E
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 18 TO 23 KNOTS. METSAT
IMAGERY AT 271200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 18.6N 143.9E. THE SYSTEM IS MOVING NORTHWARD AT 11 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 93W) PREVIOUSLY LOCATED NEAR
16.4N 143.5E IS NOW LOCATED NEAR 18.0N 143.9E, APPROXIMATELY 316 NM NORTH
OF GUAM. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY AND A 270805Z SSMIS
91 GHZ IMAGE DEPICT A BROAD AREA OF SHARP TROUGHING WITH PERSISTENT, DEEP
CONVECTIVE BANDING HIDING THE PROSPECTIVE LOW LEVEL CIRCULATON CENTER
(LLCC). A 271130Z ASCAT-C PARTIAL PASS SHOWS 15-20KT WINDS TO THE EAST OF
THE ASSESSED CENTER. ENVIRONMENTAL ANALYSIS REVEALS FAVORABLE CONDITIONS
FOR DEVELOPMENT WITH WARM (29-30 C) SST AND ROBUST POLEWARD OUTFLOW ALOFT
OFFSET BY MODERATE (15-20KTS) VERTICAL WIND SHEAR. GLOBAL MODELS INDICATE
93W WILL TRACK SLOWLY WESTWARD WITH STEADY DEVELOPMENT OVER THE NEXT 48
HOURS. THE SYSTEM WILL LIKELY STALL NEAR THE WEST OF THE NORTHERN
MARIANAS WITH STRONG MONSOONAL FLOW PERSISTING OVER THE REGION, AIDING IN
ITS DEEPENING AND DEVELOPMENT.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 18 TO 23 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1000 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
281500Z.
//
NNNN

[Hayabusa]

12z gfs goes far west than the previous runs that it initiates a binary interaction with Saola still a strong typhoon.

[Sciencerocks]

[cycloneye]

JMA upgrades to TS HAIKUI.

T2311(Haikui)
Issued at 2023/08/28 01:25 UTC
Analysis at 08/28 00 UTC
Grade TS
Scale -
Intensity -
Center position N18°25′ (18.4°)
E143°00′ (143.0°)
Direction and speed of movement W 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 30-kt wind area 220 km (120 NM)

[cycloneye]

 https://twitter.com/ForceThirteen/status/1696002031570346448

[cycloneye]

JTWC ufrades to TS.

10W HAIKUI 230828 1800 18.6N 139.6E WPAC 35 1001

[cycloneye]

10W HAIKUI 230829 1200 19.1N 137.2E WPAC 50 988

[cycloneye]

WDPN33 PGTW 291500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 10W (HAIKUI) WARNING NR
005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
INITIAL POSITION: 19.1N 137.2E
INITIAL INTENSITY: 50 KTS
GEOGRAPHIC REFERENCE: 411 NM SOUTHWEST OF IWO TO
MOVEMENT PAST 6 HOURS: WESTWARD AT 07 KTS
SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) AND PROXY VISIBLE SATELLITE
IMAGERY DEPICTS A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER
(LLCC) TO THE EAST OF AN AREA OF PERSISTENT CONVECTION WITH ROBUST
OVERSHOOTING TOPS. WHILE THE CONVECTION IS IMPRESSIVE, BASED ON THE
PROXY VISIBLE IMAGERY AND A 290918Z SSMIS 91GHZ IMAGE AND A 291202Z
AMSU-B 89GHZ IMAGE, THE VORTEX IS SIGNIFICANTLY TILTED TO THE WEST
WITH HEIGHT DUE TO PERSISTENT MODERATE EASTERLY SHEAR. THIS IS
BORN OUT IN HAFS-A CROSS SECTIONS WHICH SHOW AN EXTREMELY TILTED
VORTEX. THE LATEST IMAGERY SHOWS CONVECTION IS PUSHING EAST AGAINST
THE SHEAR, AND THE LLCC IS TUCKING BACK UNDER THE EASTERN PORTION OF
THE CDO FEATURE, BUT IT REMAINS TO BE SEEN IF THIS PUSH WILL SUSTAIN
ITSELF. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED
ON THE LLCC EVIDENT IN THE IMAGERY DESCRIBED ABOVE. THE INITIAL
INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON EVALUATION OF
THE AGENCY DVORAK CURRENT INTENSITY ESTIMATES AVERAGING T3.5 AND
THE SUBJECTIVE ESTIMATES AVERAGING ROUGHLY 55 KNOTS. THE SYSTEM IS
TRACKING WESTWARD ALONG THE SOUTHERN SIDE OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) TO THE NORTH. ENVIRONMENTAL ANALYSIS
REVEALS ROUGHLY FAVORABLE CONDITIONS, WITH WARM SSTS AND GOOD
WESTWARD AND EQUATORWARD OUTFLOW OFFSET BY THE MODERATE EASTERLY
SHEAR.

INITIAL WIND RADII BASIS: PERSISTENCE

CURRENT STEERING MECHANISM: SOUTHERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED TO THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T3.5 - 55 KTS
RJTD: T4.0 - 65 KTS
RCTP: T3.0 - 45 KTS
KNES: T3.0 - 45 KTS
CIMSS ADT: 47 KTS AT 291140Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
VWS: 15-20 KTS
SST: 30-31 CELSIUS
OUTFLOW: MODERATE EQUATORWARD

ANALYSIS CONFIDENCE:
INITIAL POSITION: MEDIUM
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: LOW

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE FORECAST POINTS IN THE LATER
PORTIONS IN THE FORECAST HAVE BEEN SHIFTED 150NM SOUTHWARD AS TRACK
UNCERTAINTY CONTINUES TO INCREASE.

FORECAST DISCUSSION: A REANALYSIS OF EARLIER MICROWAVE IMAGERY HAS
RESULTED IN A SLOWING IN THE TRACK SPEED, BUT NO MAJOR SHIFT IN THE
TRACK DIRECTION, WITH TROPICAL STORM (TS) 09W (HAIKUI) STILL
HEADING TOWARDS THE WEST-NORTHWEST ALONG THE SOUTHERN SIDE OF THE
STRONG STR FAR TO THE NORTHEAST. CONTINUING THE TREND ESTABLISHED
SIX HOURS AGO, MODEL GUIDANCE CONTINUES TO DIVERGE AT A STEADILY
INCREASING RATE, WITH THE DIVERGENCE BEGINNING AS EARLY AS TAU 36.
THE KEY DIFFERENCE FROM SIX HOURS AGO IS THAT THE ECMWF AND ITS
ENSEMBLE ARE NOW THE SOLE OUTLIERS IN TAKING THE SYSTEM ON A PATH
STRAIGHT AT OKINAWA AND ONWARDS INTO THE EAST CHINA SEA. THE
REMAINDER OF THE GUIDANCE IS TRENDING CLOSER TO THE GFS-BASED
FAMILY OF MODELS WHICH INSIST THE SYSTEM WILL TURN SHARPLY
SOUTHWEST AFTER TAU 36, PERFORM A COUNTER-CLOCKWISE LOOP, AND THEN
TRACK BACK TO THE NORTHEAST UNDER THE INFLUENCE OF A STRENGTHENING
RIDGE OVER EASTERN CHINA, AND A BINARY INTERACTION WITH A POTENTIAL
FUTURE TROPICAL CYCLONE DEVELOPING EAST OF GUAM. THE JTWC FORECAST
REMAINS CONSISTENT WITH THE PREVIOUS FORECAST AND THE CONSENSUS
MEAN TO TAU 48, THEN DEPARTS FROM THE MEAN, HEDGING TOWARDS THE
SOUTH AND WEST NEAR THE GFS ENSEMBLE MEAN. ENSEMBLE SPREAD IS LESS
THAN IT WAS EARLIER, WITH ONLY A HANDFUL OF GEFS MEMBERS SUPPORTING
THE NORTHERN TRACK. BUT THE 1000NM SPREAD BETWEEN THE GFS AND ECMWF
TRACKERS AT TAU 120 ARE INDICATIVE OF THE EXTREME UNCERTAINTY IN
THE FORECAST TRACK. HAVING BRIEFLY POKED ITS HEAD OUT OF FROM UNDER
THE CONVECTIVE MASS EARLIER IN THE DAY, THE LLCC HAS DECIDED ITS
HAD ENOUGH MOON SHINE FOR ONE NIGHT AND TUCKED BACK UNDER THE
CONVECTIVE SHIELD IN THE PAST COUPLE OF HOURS. DUE TO THE PRESENCE
OF PERSISTENT MODERATE EASTERLY SHEAR, IT REMAINS TO BE SEEN IF THE
CONVECTIVE TOWERS CURRENTLY FIRING ON THE UPSHEAR SIDE CAN ACTUALLY
CONTINUE FOR MORE THAN A BRIEF PERIOD OF TIME. SHEAR IS EXPECTED TO
REMAIN AT MODERATE LEVELS FOR THE NEXT 24 HOURS OR SO AND WILL PUT
A BRAKE ON VORTEX ALIGNMENT AND INTENSIFICATION. SHEAR IS EXPECTED
TO RELAX SOMEWHAT AFTER TAU 24, ALLOWING THE SYSTEM TO SYMMETRIZE
AND INTENSIFY AT A FASTER RATE, REACHING A PEAK OF 95 KNOTS BY TAU
72. HOWEVER, DUE TO THE EXTREME UNCERTAINTY IN THE TRACK, THE
INTENSITY GUIDANCE IS ALSO HIGHLY UNCERTAIN DUE TO THE RELATIONSHIP
BETWEEN THE TRACK AND INTENSITY. A TRACK MORE IN LINE WITH THE GFS
WILL RESULT IN A MUCH HIGHER INTENSITY PEAK, WHILE AN ECMWF-LIKE
TRACK WILL LEAD TO A LOWER PEAK.

MODEL DISCUSSION: AS DISCUSSED ABOVE, DETERMINISTIC TRACK GUIDANCE
EXHIBITS AND UNUSUALLY LARGE SPREAD OF NEAR 1000NM AT TAU 120,
WHILE ENSEMBLE MEMBER SHOW A SIMILARLY WIDE SPREAD. THE JTWC TRACK
LIES CLOSE TO THE CONSENSUS MEAN TO TAU 48, THEN IS SIGNIFICANTLY
SLOWER AND TO THE SOUTH OF THE MEAN THROUGH THE REMAINDER OF THE
FORECAST, MOST CLOSELY TRACKING THE GFS ENSEMBLE MEAN. CONFIDENCE
IS VERY LOW THROUGH THE ENTIRE FORECAST PERIOD AND MAJOR SHIFTS IN
THE TRACK CAN BE EXPECTED IN FUTURE FORECASTS AS THE STEERING
PATTERN CONTINUES TO EVOLVE. INTENSITY GUIDANCE IS VERY MIXED AS
WELL, WITH THE COAMPS-TC (BOTH VERSIONS) AND THE ENSEMBLE MEAN
INDICATING RAPID INTENSIFICATION (RI) AFTER TAU 24, TO A PEAK NEAR
150 KNOTS. HOWEVER, IN LIGHT OF THE FACT THAT THE COAMPS-TC TRACK
IS CLOSE TO THE GFS DETERMINISTIC, IT IS CURRENTLY ASSESSED AS
UNLIKELY. THE JTWC FORECAST LIES ON TOP OF THE CONSENSUS MEAN WITH
LOW CONFIDENCE, AND MAJOR CHANGES IN THE TRACK FORECAST WILL RESULT
IN LARGE SHIFTS IN THE INTENSITY FORECAST.

FORECAST CONFIDENCE:
TRACK 0 - 72 HR: LOW
TRACK 72-120 HR: LOW
INTENSITY 0 - 72 HR: LOW
INTENSITY 72-120 HR: LOW//

[Hayabusa]

00Z

[Sciencerocks]