WPAC: CHANTHU - Post-Tropical

[Yellow Evan]

Cat 5 only makes sense if internal AODT numbers support it. SAB and JTWC do not support such an intensity. Honestly this is in the early stages of an ERC so probably been steady in intensity for a while.

[Kingarabian]

Cat.5 all day for me. Dvorak won't support it for now but microwave clearly does. Eyewall strength is off the temperature brightness scale, along with the core being tight, compact and perfectly circular.

[StormTracker89]

Cat 5 only makes sense if internal AODT numbers support it. SAB and JTWC do not support such an intensity. Honestly this is in the early stages of an ERC so probably been steady in intensity for a while.

Dvorak is pretty much useless in a case like this with an eye around 5nm wide. Even ADT can't hold track on it. So in the absence of that, use what you have which is appearance, analogs, persistence. And the last "good" ADT eye fix which had an eye temp of +16C was at 0340Z. By that measure, at that time it likely was at least T7.0/140kt. So I'm on board with supporting the 140kt.

[Hayabusa]

The GFS is the westernmost this run, usually it's the Euro.

[Yellow Evan]

Cat 5 only makes sense if internal AODT numbers support it. SAB and JTWC do not support such an intensity. Honestly this is in the early stages of an ERC so probably been steady in intensity for a while.

Nevermind, this might still be intensifying. Hopefully we get a good intensity estimate from somewhere.

[Hayabusa]

Revised 00Z 120 to 130

19W CHANTHU 210908 0600 15.6N 131.3E WPAC 140 922
19W CHANTHU 210908 0000 16.0N 132.3E WPAC 130 932
19W CHANTHU 210907 1800 16.3N 133.5E WPAC 125 937

[Kingarabian]

Revised 00Z 120 to 130

19W CHANTHU 210908 0600 15.6N 131.3E WPAC 140 922
19W CHANTHU 210908 0000 16.0N 132.3E WPAC 130 932
19W CHANTHU 210907 1800 16.3N 133.5E WPAC 125 937

Maybe sub 900 pressure since the eye is so small.

[Hayabusa]

Latest track forecast making a close approach to Luzon

[mrbagyo]

ultra weird structure revealed by latest microwave pass

[StormTracker89]

ultra weird structure revealed by latest microwave pass
https://i.imgur.com/Cm6BjgF.jpg

Looks like an embryo or even the Alien!

[Yellow Evan]

Revised 00Z 120 to 130

19W CHANTHU 210908 0600 15.6N 131.3E WPAC 140 922
19W CHANTHU 210908 0000 16.0N 132.3E WPAC 130 932
19W CHANTHU 210907 1800 16.3N 133.5E WPAC 125 937

Maybe sub 900 pressure since the eye is so small.

This storm is too small for a really insane pressure. CKZ supports ~920 mbar.

[aspen]

IMO, this is closer to 150-155 kt now. I’m surprised by how long the pinhole structure has lasted for.

[doomhaMwx]

06Z forecast tracks from different agencies.

[aspen]

The eye is quickly filling in now, looks like an EWRC might be starting.

[WAcyclone]

A new SMAP pass should come in in a few minutes but Chanthu may be very close to the eastern edge of the swath (but hopefully not too close!).

[StormTracker89]

Will be interesting to see how the forecast track may change in light of the 06Z GEFS run, with a bifurcation taking shape, with roughly even split between a poleward turn over or just east of Taiwan, and or a flatter trajectory towards the vicinity of Hong Kong. Will the agencies stick with their current forecasts projecting a track poleward west of Taiwan or start to flatten it out? https://www.weathernerds.org/models/gefs.html?&inittype=zoom&initfield=MSLP_Surface&initcycle=determine&initfhour=108&initimdimx=1050&initimdimy=750&initrange=32.604000000000:105.404761904685:4.788000000000:149.195238095220&initcx1=120&initcy1=326&initcx2=512&initcy2=600&initcross=False&initsound=False&initsoundx=115&initsoundy=321&initloop=False&initoverlay=False&initlstart=000&initlend=336&initlint=6&initol1=MSLP_Surface&initol2=null&initol3=null&initol4=null&initol5=null&initcities=Off&inithgwys=Off&inittracks=On&initlows=On&initlatlon=Off

[WAcyclone]

SMAP got it but it looks like the extremely small core may have been undersampled by the instrument. The highest pixel value windspeed obtained was about 88 kt 10-minute (~98 kt 1 minute). Nothing can replace recon, unfortunately.

[dexterlabio]

WPAC having its 2nd Category 5 in 2021 gives this year a slight edge over 2020, although it remains to be seen if the basin will be more consistent in producing more potent storms towards the end of the year.

[doomhaMwx]

EWRC ongoing

[StormTracker89]

SMAP got it but it looks like the extremely small core may have been undersampled by the instrument. The highest pixel value windspeed obtained was about 88 kt 10-minute (~98 kt 1 minute). Nothing can replace recon, unfortunately.

https://i.imgur.com/JlFiSb1.jpg

Not surprising given that nearly the entire core of the system would fit in one 40-km pixel. Resolution of SMAP just isn't good enough to effectively capture a super small system such as this. Too bad we don't have any SAR hits either. That would provide measurements nearly as good as airborne recon.