WPAC: CHANTHU - Post-Tropical

[Hayabusa]

Still a little way to go before reaching Meranti levels it must reach those eye temperatures below, right now it's at 16 C
13/12Z is where Meranti's best track at peak 170 knots.

2016SEP13 103000 7.1 915.6 143.0 7.1 7.3 7.3 NO LIMIT OFF OFF 20.16 -78.86 EYE 20 IR 80.6 20.36 -123.15 SPRL HIM-8 31.3
2016SEP13 110000 7.1 915.5 143.0 7.1 7.3 7.3 NO LIMIT OFF OFF 20.53 -78.74 EYE 20 IR 84.6 20.39 -123.05 SPRL HIM-8 31.4
2016SEP13 113000 7.1 915.5 143.0 7.1 7.2 7.2 NO LIMIT OFF OFF 20.24 -78.62 EYE 20 IR 84.6 20.53 -122.85 COMBO HIM-8 31.6
2016SEP13 120000 7.2 912.5 146.0 7.2 7.2 7.2 NO LIMIT OFF OFF 20.55 -78.12 EYE 20 IR 84.6 20.47 -122.86 SPRL HIM-8 31.6
2016SEP13 124000 7.2 910.1 146.0 7.2 7.2 7.2 NO LIMIT OFF OFF 21.18 -77.87 EYE 20 IR 84.6 20.52 -122.73 SPRL HIM-8 31.7
2016SEP13 130000 7.2 910.1 146.0 7.2 7.1 7.1 NO LIMIT OFF OFF 20.47 -77.28 EYE 20 IR 84.6 20.54 -122.67 COMBO HIM-8 31.8
2016SEP13 133000 7.2 910.1 146.0 7.2 7.1 7.1 NO LIMIT OFF OFF 21.54 -77.17 EYE 20 IR 84.6 20.58 -122.57 COMBO HIM-8 31.9
2016SEP13 141000 7.2 910.1 146.0 7.1 7.2 7.2 NO LIMIT ON OFF 21.05 -77.96 EYE 21 IR 84.6 20.67 -122.40 SPRL HIM-8 32.1
2016SEP13 143000 7.2 910.1 146.0 7.1 7.2 7.2 NO LIMIT ON OFF 20.89 -77.93 EYE 20 IR 84.6 20.70 -122.34 COMBO HIM-8 32.2
2016SEP13 151000 7.2 910.1 146.0 7.1 7.1 7.1 NO LIMIT ON OFF 20.94 -77.31 EYE 20 IR 84.6 20.77 -122.22 COMBO HIM-8 32.3
2016SEP13 154000 7.2 910.1 146.0 7.1 7.0 7.0 NO LIMIT ON OFF 20.81 -76.91 EYE 20 IR 84.6 20.71 -121.92 COMBO HIM-8 32.5
2016SEP13 161000 7.2 910.1 146.0 7.1 7.1 7.1 NO LIMIT ON OFF 21.07 -77.37 EYE 20 IR 84.6 20.76 -121.94 COMBO HIM-8 32.5

[mrbagyo]

The eye is starting to appear on Aparri's radar
https://i.imgur.com/eIPzCJQ.gif

I know you're very knowledgeable with the geography in this area. Can you point out which observation station/area to monitor to get some sort of idea on Chanthu's actual numbers?

There are synoptic station in Basco ( 98134) and Itbayat (98132) Island.
There's also an AWS in Sta. Ana Cagayan.

[Hayabusa]

I am looking forward to the AMSU estimate, it estimated 179 knots peak for Meranti the highest at that time before being taken over by Goni at 181 knots.

[mrbagyo]

[NotoSans]

 https://twitter.com/squirtleinhk/status/1436212476329136128

[Hayabusa]

TPPN11 PGTW 100620

A. SUPER TYPHOON 19W (CHANTHU)

B. 10/0600Z

C. 17.83N

D. 123.50E

E. ONE/HMWRI8

F. T7.5/7.5/D2.0/24HRS STT: D0.5/03HRS

G. IR/EIR/VIS/MSI

H. REMARKS: 07A/PBO IRREG EYE/ANMTN. WMG EYE SURROUNDED BY CMG
YIELDS AN E# OF 6.5. ADDED 1.0 EYE ADJUSTMENT FOR CMG, TO YIELD
A DT OF 7.5. MET AND PT AGREE. DBO DT.

I. ADDITIONAL POSITIONS: NONE


HEINS

[dexterlabio]

Looks like Chanthu will be missing Northeast Luzon by a few miles, which means the core will have more time uninterrupted over water, thus increasing the chances for further intensification. I wonder if it can snatch Surigae's record as the strongest WPAC typhoon this year.

It will be terrible for those in the Batanes islands and Taiwan if that happens though. While Meranti's direct passage in Itbayat provided insightful wind and pressure readings, the island sustained tremendous damage that even the natives living there who are already used to typhoons said that Meranti is the worst one they experienced.

[sikkar]

Is PAGASA website down?

[Hayabusa]

19W CHANTHU 210910 0600 17.9N 123.4E WPAC 145 916

[Yellow Evan]

TXPQ29 KNES 100652
TCSWNP

A. 19W (CHANTHU)

B. 10/0530Z

C. 17.8N

D. 123.5E

E. ONE/HIMAWARI-8

F. T6.5/6.5

G. IR/EIR/VIS

H. REMARKS...THIS INTENSITY ESTIMATE WAS DERIVED USING 4 KM IR DATA. AN
EYE EMBEDDED WITHIN CMG RESULTS IN AN ENO OF 6.5. A WMG EYE SURROUNDED
BY CMG RESULTS IN AN EADJ OF +1.0 GIVING A DT OF 7.5. THE MET IS 7.0
BASED ON A RAPIDLY DEVELOPING TREND IN APPARENT INTENSITY OVER THE
PAST 24 HOURS. THE PT IS 7.5. THE FT IS BASED ON CONSTRAINTS LIMITING
CHANGE IN INTENSITY TO 1.5 T NUMBERS OVER 12 HOURS. THE AVERAGE DVORAK
DT OVER THE PAST 6 HOURS DOES NOT JUSTIFY BREAKING CONSTRAINTS FOR THIS
CLASSIFICATION.

I. ADDL POSITIONS

NIL


...HOSLEY

Not sure how applicable said constraint is here.

[Yellow Evan]

19W CHANTHU 210910 0600 17.9N 123.4E WPAC 145 916

Lmao this is out of character for the JTWC nowadays.

[StormTracker89]

19W CHANTHU 210910 0600 17.9N 123.4E WPAC 145 916

Lmao this is out of character for the JTWC nowadays.

Out of character how?

[Sciencerocks]

19W CHANTHU 210910 0600 17.9N 123.4E WPAC 145 916

Lmao this is out of character for the JTWC nowadays.

Out of character how?

Too conservative. This thing is at least 155 knots.

[mrbagyo]

Looks like PAGASA will go with 115 knots - 10 min (T7.5)?
 https://twitter.com/johnarielrojas/status/1436228047854735365

[Kingarabian]

TXPQ29 KNES 100652
TCSWNP

A. 19W (CHANTHU)

B. 10/0530Z

C. 17.8N

D. 123.5E

E. ONE/HIMAWARI-8

F. T6.5/6.5

G. IR/EIR/VIS

H. REMARKS...THIS INTENSITY ESTIMATE WAS DERIVED USING 4 KM IR DATA. AN
EYE EMBEDDED WITHIN CMG RESULTS IN AN ENO OF 6.5. A WMG EYE SURROUNDED
BY CMG RESULTS IN AN EADJ OF +1.0 GIVING A DT OF 7.5. THE MET IS 7.0
BASED ON A RAPIDLY DEVELOPING TREND IN APPARENT INTENSITY OVER THE
PAST 24 HOURS. THE PT IS 7.5. THE FT IS BASED ON CONSTRAINTS LIMITING
CHANGE IN INTENSITY TO 1.5 T NUMBERS OVER 12 HOURS. THE AVERAGE DVORAK
DT OVER THE PAST 6 HOURS DOES NOT JUSTIFY BREAKING CONSTRAINTS FOR THIS
CLASSIFICATION.

I. ADDL POSITIONS

NIL


...HOSLEY

Not sure how applicable said constraint is here.

Too bad the initial idea behind Dvorak - which was for a set of rules and guidelines to be followed so that the best intensity for a TC is found - is now lost and varies based on each persons preference/bias.

[WALL-E]

TXPQ29 KNES 100652
TCSWNP

A. 19W (CHANTHU)

B. 10/0530Z

C. 17.8N

D. 123.5E

E. ONE/HIMAWARI-8

F. T6.5/6.5

G. IR/EIR/VIS

H. REMARKS...THIS INTENSITY ESTIMATE WAS DERIVED USING 4 KM IR DATA. AN
EYE EMBEDDED WITHIN CMG RESULTS IN AN ENO OF 6.5. A WMG EYE SURROUNDED
BY CMG RESULTS IN AN EADJ OF +1.0 GIVING A DT OF 7.5. THE MET IS 7.0
BASED ON A RAPIDLY DEVELOPING TREND IN APPARENT INTENSITY OVER THE
PAST 24 HOURS. THE PT IS 7.5. THE FT IS BASED ON CONSTRAINTS LIMITING
CHANGE IN INTENSITY TO 1.5 T NUMBERS OVER 12 HOURS. THE AVERAGE DVORAK
DT OVER THE PAST 6 HOURS DOES NOT JUSTIFY BREAKING CONSTRAINTS FOR THIS
CLASSIFICATION.

I. ADDL POSITIONS

NIL


...HOSLEY

Not sure how applicable said constraint is here.

Too bad the initial idea behind Dvorak - which was for a set of rules and guidelines to be followed so that the best intensity for a TC is found - is now lost and varies based on each persons preference/bias.

Every piece supports a clear FT7.0+, while there is this DT constraint, so let's stick to the constraint, as the storm should strictly intensify accordingly.

[StormTracker89]

Lmao this is out of character for the JTWC nowadays.

Out of character how?

Too conservative. This thing is at least 155 knots.

Well they are certainly closer to reality than all the other agencies like Pagasa and JMA. Of course we'll never know for certain without recon but I agree it's up over 145.

[Yellow Evan]

19W CHANTHU 210910 0600 17.9N 123.4E WPAC 145 916

Lmao this is out of character for the JTWC nowadays.

Out of character how?

The JTWC isn’t hugging there own Dvorak estimates simply because SAB decided to enforce their Dvorak constraints.

[Yellow Evan]

----- Current Analysis -----
Date : 10 SEP 2021 Time : 074000 UTC
Lat : 18:07:47 N Lon : 123:20:23 E


CI# /Pressure/ Vmax
7.3 / 911.7mb/149.0kt


Final T# Adj T# Raw T#
7.3 7.4 7.4

Estimated radius of max. wind based on IR : 17 km

Center Temp : +15.9C Cloud Region Temp : -78.7C

Scene Type : EYE

[WALL-E]

TPPN11 PGTW 100903

A. SUPER TYPHOON 19W (CHANTHU)

B. 10/0830Z

C. 18.22N

D. 123.31E

E. ONE/HMWRI8

F. T7.5/7.5/D2.0/24HRS STT: S0.0/03HRS

G. IR/EIR/VIS/MSI

H. REMARKS: 07A/PBO IRREG EYE/ANMTN. WMG EYE SURROUNDED BY CMG
YIELDS AN E# OF 6.5. ADDED 1.0 EYE ADJUSTMENT FOR CMG, TO YIELD
A DT OF 7.5. MET AND PT AGREE. DBO DT.

I. ADDITIONAL POSITIONS:
10/0436Z 17.65N 123.57E ATMS
10/0527Z 17.73N 123.57E ATMS


HEINS

PGTW issued FT7.5 for 09z, now wait for 12z and a 155KT