WPAC: SAOLA - Post-Tropical

[Sciencerocks]

 https://twitter.com/zoom_earth/status/1695580285138514076

[Teban54]

[cycloneye]

https://i.postimg.cc/sDmyfHJh/image.png

Irwin comming at EPAC. The northern Hemisphere is very active right now with ACE well above average at 325.9.

[Sciencerocks]

[doomhaMwx]

https://i.postimg.cc/sDmyfHJh/image.png

Well, the majority of S2K members are from the US, so that's understandable. This will become even more obvious when Saola and Idalia are simultaneously nearing/making landfall in ~3 days' time but with significant differences in intensity.

[dexterlabio]

https://i.postimg.cc/sDmyfHJh/image.png

Already happened before in 2018 with Mangkhut and Florence. It's understandable given where the majority of forum users are from. Funny though that Idalia is not even named yet

[mrbagyo]

https://i.postimg.cc/sDmyfHJh/image.png

Saola is the apple of the eye in Tybbs forum (currently has 46 pages)
meanwhile Idalia only has 2 pages.

[FireRat]

https://i.postimg.cc/sDmyfHJh/image.png

This is way too funny!! So true, with Saola being such a nice-looking powerhouse too. Watch it make a run at C5 in the next 24 hrs

[Cyclenall]

I've mainly been following Saola, even when it was a TD due to the unique southward track and landmass impacts. Looking at the forecast discussion and the steering maps like 500 mb I still don't know what is causing this to move due south for a long distance. Doing so while being a major is also amazing.

[Hayabusa]

HFSA really loves to go overhype mode more than the HWRF...

[Hayabusa]

Smap 09z only 82kts, either legit or the storm is too small to get a reliable estimate

WP, 09, 202308270934, 30, SMAP, IR, , 1620N, 12320E, , 1, 77, 1, , , , 34, NEQ, 45, 58, 0, 0, , , , , 1, 0, , W, NASA, RSS, , , , , , , , , , , , , , , , , , , , , , , , , , , , 1, max. wind is 10 minute sustained
WP, 09, 202308270934, 30, SMAP, IR, , 1620N, 12320E, , 1, 77, 1, , , , 50, NEQ, 30, 25, 0, 0, , , , , 1, 0, , W, NASA, RSS, , , , , , , , , , , , , , , , , , , , , , , , , , , , 1, max. wind is 10 minute sustained
WP, 09, 202308270934, 30, SMAP, IR, , 1620N, 12320E, , 1, 77, 1, , , , 64, NEQ, 19, 17, 0, 0, , , , , 1, 0, , W, NASA, RSS, , , , , , , , , , , , , , , , , , , , , , , , , , , , 1, max. wind is 10 minute sustained

12z jtwc up to 125 kts

09W SAOLA 230827 1200 16.2N 123.2E WPAC 125 932

[doomhaMwx]

Moving east now.

[Sciencerocks]

[cycloneye]

09W SAOLA 230827 1800 16.2N 123.6E WPAC 110 932

[underthwx]

Looks like Saola is moving South-Souheast, or parallel to the Northeastern coast of the Phillipines? My fiancee is concerned about some of her family in Metro Manila, mainly her brother who lives there. The rest are in Igbarras, and Western Visayas. Will Saola(Goring), pose flooding/landslide threats in either region?

[cycloneye]

WDPN32 PGTW 272100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (SAOLA) WARNING NR 017//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
INITIAL POSITION: 16.0N 123.7E
INITIAL INTENSITY: 110 KTS
GEOGRAPHIC REFERENCE: 177 NM EAST-NORTHEAST OF MANILA,
PHILIPPINES
MOVEMENT PAST 6 HOURS: EAST-SOUTHEASTWARD AT 04 KTS
SIGNIFICANT WAVE HEIGHT: 42 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TYPHOON (TY) 09W HAS WEAKENED CONSIDERABLY OVER THE PAST SIX HOURS
WITH THE RECENT LOSS OF THE EYE AND A SHRINKING, MORE ASYMMETRIC
CONVECTIVE CORE AS DEPICTED IN THE ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY. A 271656Z AMSR2 89 GHZ MICROWAVE IMAGE REVEALS A
SMALL MICROWAVE EYE, WHICH SUPPORTS THE INITIAL POSITION WITH HIGH
CONFIDENCE, AND AN ASYMMETRIC CORE WITH DECAYING DEEP CONVECTION
OVER THE NORTHERN QUADRANT. THE EYEWALL REMAINS INTACT BUT HAS A
DEVELOPING BREAK OVER THE NORTH QUADRANT. THE CIMSS M-PERC PRODUCT
SHOWS INCREASING PROBABILITIES (90-100 PERCENT) FOR AN EYEWALL
REPLACEMENT CYCLE (ERC), HOWEVER, HIGH RESOLUTION MICROWAVE IMAGERY
HAS BEEN SPARSE SO IT'S DIFFICULT TO VERIFY AN ERC. ADDITIONALLY,
INTERACTION WITH LAND AND UPWELLING COOLER WATER ARE ALSO
CONTRIBUTING TO THE RECENT WEAKENING TREND. THE INITIAL INTENSITY
OF 110 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE CURRENT
INTENSITY ESTIMATES FROM PGTW, KNES AND RJTD.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA

CURRENT STEERING MECHANISM: NEAR-EQUATORIAL (NER) RIDGE ENTRENCHED
TO THE SOUTH WITH A WEAK EXTENSION OF THE NER TO THE EAST,
SEPARATING 09W FROM A DEVELOPING TROPICAL SYSTEM (INVEST 93W) NEAR
THE NORTHERN MARIANAS.

AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T5.5 - 102 KTS
RJTD: T6.0 - 115 KTS
KNES: T5.5 - 102 KTS
CIMSS ADT: 102 KTS AT 271730Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
VWS: 5-10 KTS
SST: 30-31 CELSIUS
OUTFLOW: MODERATE RADIAL
OTHER FACTORS: DYNAMIC OCEAN COOLING

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: BASED ON THE CLEAR WEAKENING TREND,
FORECAST INTENSITIES THROUGH TAU 36 HAVE BEEN DECREASED
SIGNIFICANTLY.

FORECAST DISCUSSION: TY 09W HAS STARTED TO SLOWLY TURN EASTWARD AND
NOW APPEARS TO BE TURNING EAST-NORTHEASTWARD AS EXPECTED. 09W IS
FORECAST TO ACCELERATE POLEWARD OVER THE NEXT 24 HOURS. FURTHER
WEAKENING IS EXPECTED OVER THE NEXT 12 HOURS THEN A STEADY
REINTENSIFICATION PHASE SHOULD OCCUR AS THE SYSTEM TRACKS AWAY FROM
LUZON AND OVER WARMER SST. AFTER TAU 24, STEERING SHOULD TRANSITION
FROM THE NER TO A BUILDING SUBTROPICAL RIDGE (STR) OVER THE EAST
CHINA SEA. THIS WILL ALLOW TY 09W TO TRACK WEST-NORTHWESTWARD
THROUGH TAU 120. THE STR, ESPECIALLY THE WESTERN EXTENT, SHOULD
REMAIN WEAK DUE TO THE PRESENCE OF A STRONG, BROAD UPPER LEVEL LOW
AND TROUGH DEVELOPING OVER NORTHEAST ASIA THUS TRACK SPEEDS WILL
REMAIN CLIMATOLOGICALLY SLOW. TY 09W WILL PEAK NEAR 125 KNOTS BY
TAU 72 WITH STEADY WEAKENING IN THE EXTENDED FORECAST PERIOD DUE TO
INTERACTION WITH TAIWAN AND SOUTHEAST CHINA.

MODEL DISCUSSION: WITH THE EXCEPTION OF NAVGEM, NUMERICAL MODEL
GUIDANCE IS IN GOOD AGREEMENT THROUGH TAU 72 LENDING HIGH
CONFIDENCE TO THE JTWC FORECAST TRACK. AFTER TAU 72, TRACK GUIDANCE
DIVERGES WITH A 320 NM CROSS-TRACK SPREAD IN SOLUTIONS AT TAU 120.
THIS INCREASING UNCERTAINTY AND LOW TRACK CONFIDENCE IS REFLECTED
IN THE 271200Z EPS AND GEFS ENSEMBLES, WHICH SHOW A LARGE SPREAD.
BOTH THE GFS DETERMINISTIC SOLUTION AND GEFS ENSEMBLE SUGGEST A
PROBLEMATIC, POTENTIAL SCENARIO WHERE INVEST 93W STRENGTHENS AND
TRACKS WESTWARD TOWARD TAIWAN, CLOSING TO ABOUT 590 NM AT TAU 120.
SOME DEGREE OF INTERACTION THEN OCCURS BETWEEN THE TWO SYSTEMS.
THIS POTENTIAL SCENARIO IS COMPLEX AND WILL BE MONITORED CLOSELY.

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

[cycloneye]

09W SAOLA 230828 0000 16.8N 124.4E WPAC 95 959

[cycloneye]

WDPN32 PGTW 280300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (SAOLA) WARNING NR 018//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
INITIAL POSITION: 16.8N 124.3E
INITIAL INTENSITY: 115 KTS
GEOGRAPHIC REFERENCE: 232 NM NORTHEAST OF MANILA, PHILIPPINES
MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 10 KTS
SIGNIFICANT WAVE HEIGHT: 42 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
AS DEPICTED IN ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY,
TYPHOON (TY) 09W ACCELERATED ABRUPTLY NORTHEASTWARD OVER THE PAST
SIX HOURS AND RAPIDLY REFORMED A SMALL 6NM EYE. THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON ANIMATED
MULTISPECTRAL SATELLITE IMAGERY. A 272220Z SSMIS 91 GHZ COLOR
COMPOSITE MICROWAVE IMAGE SHOWS A SMALL 40 NM INNER EYEWALL
SURROUNDED BY A MOAT AND A FRAGMENTED OUTER EYEWALL. AS MENTIONED IN
THE 271800Z PROGNOSTIC REASONING MESSAGE, THE CIMSS M-PERC
PRODUCT INDICATED A HIGH PROBABILITY OF AN EYEWALL REPLACEMENT
CYCLE (ERC) OCCURRING. THE MOST RECENT PROBABILITIES HAVE DROPPED
FROM 90 PERCENT TO ABOUT 50 PERCENT BUT STILL SUGGEST AN IMMINENT
ERC.

INITIAL WIND RADII BASIS: SAR DATA

CURRENT STEERING MECHANISM: NEAR-EQUATORIAL (NER) RIDGE ENTRENCHED
TO THE SOUTH WITH A WEAK EXTENSION OF THE NER TO THE EAST,
SEPARATING 09W FROM A DEVELOPING TROPICAL SYSTEM (INVEST 93W) NEAR
THE NORTHERN MARIANAS.

AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T6.0 - 115 KTS
RJTD: T5.0 - 90 KTS
RCTP: T6.5 - 127 KTS
KNES: T5.5 - 102 KTS
CIMSS SATCON: 78 KTS AT 272220Z
CIMSS ADT: 84 KTS AT 272330Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
VWS: 5-10 KTS
SST: 29-30 CELSIUS
OUTFLOW: MODERATE RADIAL

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: AFTER A SHORT PERIOD OF WEAKENING, TY 09W
APPEARS TO BE POISED TO REINTENSIFY TO A PEAK OF 130 KNOTS BY TAU
24. THE SYSTEM SHOULD MAINTAIN SUPER TYPHOON STRENGTH THROUGH AT
LEAST TAU 36. AFTER TAU 24, STEERING SHOULD TRANSITION FROM THE NER
TO A BUILDING SUBTROPICAL RIDGE (STR) OVER THE EAST CHINA SEA. THIS
WILL ALLOW TY 09W TO TRACK WEST-NORTHWESTWARD THROUGH TAU 120. THE
STR, ESPECIALLY THE WESTERN EXTENT, SHOULD REMAIN WEAK DUE TO THE
PRESENCE OF A STRONG, BROAD UPPER LEVEL LOW AND TROUGH DEVELOPING
OVER NORTHEAST ASIA THUS TRACK SPEEDS WILL REMAIN CLIMATOLOGICALLY
SLOW. STEADY WEAKENING WILL OCCUR IN THE EXTENDED FORECAST PERIOD DUE
TO LAND INTERACTION WITH TAIWAN AND SOUTHEAST CHINA.

MODEL DISCUSSION: WITH THE EXCEPTION OF NAVGEM, NUMERICAL MODEL
GUIDANCE IS IN GOOD AGREEMENT THROUGH TAU 72 LENDING HIGH
CONFIDENCE TO THE JTWC FORECAST TRACK. THERE IS MEDIUM CONFIDENCE
IN THE JTWC INTENSITY FORECAST DUE TO POTENTIAL FOR AN ERC, WHICH
MAY TEMPORARILY WEAKEN THE SYSTEM. HOWEVER, CONDITIONS APPEAR
FAVORABLE FOR SIGNIFICANT INTENSIFICATION OVER THE NEXT TWO DAYS
WITH RAPID INTENSIFICATION GUIDANCE TRIGGERED AND THE 271800Z
COAMPS-TC ENSEMBLE SHOWING A 30-40 PERCENT PROBABILITY OF RAPID
INTENSIFICATION OCCURRING THROUGH TAU 48. AFTER TAU 72, TRACK
GUIDANCE DIVERGES WITH A 390 NM CROSS-TRACK SPREAD IN SOLUTIONS AT
TAU 120. THIS INCREASING UNCERTAINTY AND LOW TRACK CONFIDENCE IS
REFLECTED IN THE 271800Z EPS AND GEFS ENSEMBLES, WHICH SHOW A LARGE
SPREAD. BOTH THE GFS DETERMINISTIC SOLUTION AND GEFS ENSEMBLE
SUGGEST A PROBLEMATIC, POTENTIAL SCENARIO WHERE INVEST 93W
STRENGTHENS AND TRACKS WESTWARD TOWARD TAIWAN, CLOSING TO ABOUT 590
NM AT TAU 120. SOME DEGREE OF BINARY INTERACTION THEN OCCURS BETWEEN
THE TWO SYSTEMS. THIS POTENTIAL SCENARIO IS COMPLEX AND WILL BE
MONITORED CLOSELY.


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

[doomhaMwx]

It appears Saola's unexpected weakening after moving away from Luzon can also be attributed to the imminent (or maybe ongoing) EWRC mentioned by JTWC. The forming secondary eyewall captured by SSMIS at ~22Z is still visible on more recent PAGASA radar images.

[xtyphooncyclonex]

Saola seems to be part of a phenomenon my amateur eye has seen this year. I've noticed that there has been an overall breakdown in our steering patterns that's made storms linger for longer and exhibit erratic tracks --- seen with Mawar, Doksuri, Khanun, Lan, and now, Saola. This pattern also seems to have indirectly made storms rack up more ACE than usual. Not sure if it's exclusive to 2023, however.

With Khanun, rather than simply striking China, it ended up meandering the Ryukyus. With Doksuri, Mawar, and Lan, they simply moved slower than normal for most of their lifetimes (especially given Lan's latitude, where storms usually sprint).