WPAC: HAGIBIS - Post-Tropical

[euro6208]

HWRF with a secondary peak within the next 12 hours.

[Highteeld]

Likely overestimated by 15-20 knots due to JTWC goofy protocol

20W HAGIBIS 191008 0000 16.9N 143.7E WPAC 135 921

[euro6208]

Amazing that a small volcanic island (indicated by a red pointing arrow) out of nowhere in the Pacific got smacked by a pinhole.

[1900hurricane]

Eyewall replacement appears to be moving along without much issue.

[1900hurricane]

Likely overestimated by 15-20 knots due to JTWC goofy protocol

20W HAGIBIS 191008 0000 16.9N 143.7E WPAC 135 921

Believe it or not, JTWC might actually be somewhat close to reality in this case. Data from Wilma '05 in particular showed that the max winds can drop considerably at first as core pressure gradient transitions and the outer eyewall begins to take over. That doesn't change the likely considerable underestimation earlier though.

[Highteeld]

https://www.nrlmry.navy.mil//tcdat/tc2019/WP/WP202019/png/Infrared/himawari8/201910071020_WP202019_ahi_himawari8_Infrared_130.0_covg100p0_res1km.png
https://www.nrlmry.navy.mil/tcdat/tc15/EPAC/20E.PATRICIA/ir/ols/1km/20151023.1344.f19.x.ir1km.20EPATRICIA.175kts-880mb-172N-1056W.100pc.jpg
https://www.nrlmry.navy.mil/tcdat/tc05/ATL/25L.WILMA/ir/ols/1km/20051019.1233.f14.x.ir1km.25LWILMA.150kts-882mb-173N-828W.jpg

Edited for better resolution:

[Highteeld]

Likely overestimated by 15-20 knots due to JTWC goofy protocol

20W HAGIBIS 191008 0000 16.9N 143.7E WPAC 135 921

Believe it or not, JTWC might actually be somewhat close to reality in this case. Data from Wilma '05 in particular showed that the max winds can drop considerably at first as core pressure gradient transitions and the outer eyewall begins to take over. That doesn't change the likely considerable underestimation earlier though.

135 knots would be pretty phenomenal at this point, but I guess it's possible.

[Highteeld]

https://www.nrlmry.navy.mil//tcdat/tc2019/WP/WP202019/png/Infrared/himawari8/201910071020_WP202019_ahi_himawari8_Infrared_130.0_covg100p0_res1km.png
https://www.nrlmry.navy.mil/tcdat/tc15/EPAC/20E.PATRICIA/ir/ols/1km/20151023.1344.f19.x.ir1km.20EPATRICIA.175kts-880mb-172N-1056W.100pc.jpg
https://www.nrlmry.navy.mil/tcdat/tc05/ATL/25L.WILMA/ir/ols/1km/20051019.1233.f14.x.ir1km.25LWILMA.150kts-882mb-173N-828W.jpg

Edited for better resolution:

https://www.nrlmry.navy.mil//tcdat/tc2019/WP/WP202019/png/Infrared/himawari8/201910071020_WP202019_ahi_himawari8_Infrared_130.0_covg100p0_res1km.png

1040z is pretty violent too:

[Highteeld]

Likely overestimated by 15-20 knots due to JTWC goofy protocol

20W HAGIBIS 191008 0000 16.9N 143.7E WPAC 135 921

Believe it or not, JTWC might actually be somewhat close to reality in this case. Data from Wilma '05 in particular showed that the max winds can drop considerably at first as core pressure gradient transitions and the outer eyewall begins to take over. That doesn't change the likely considerable underestimation earlier though.

One other question I have is this: does that apply to sfc winds or FL? IIRC, Wilma was before the time of SFMR, so the way we measured that storm may not yield the same results as current protocol. IDK, just thinking out loud... just seems like SFMR and FL winds have a bigger gap during ERC's, while the gap is very small to nil during RI phases (assuming we believe SFMR is a decent benchmark, that is). All anecdotal on my behalf.

[Highteeld]

Moat grows

[Tailspin]

https://imgur.com/WDaqSHN

Looks like maybe there some subsidence going on in the RFQ. Wonder's if it the begining
of a centre collapse.¯\_(ツ)_/¯.

[1900hurricane]

Likely overestimated by 15-20 knots due to JTWC goofy protocol

20W HAGIBIS 191008 0000 16.9N 143.7E WPAC 135 921

Believe it or not, JTWC might actually be somewhat close to reality in this case. Data from Wilma '05 in particular showed that the max winds can drop considerably at first as core pressure gradient transitions and the outer eyewall begins to take over. That doesn't change the likely considerable underestimation earlier though.

One other question I have is this: does that apply to sfc winds or FL? IIRC, Wilma was before the time of SFMR, so the way we measured that storm may not yield the same results as current protocol. IDK, just thinking out loud... just seems like SFMR and FL winds have a bigger gap during ERC's, while the gap is very small to nil during RI phases (assuming we believe SFMR is a decent benchmark, that is). All anecdotal on my behalf.

Both I think, although the data set is rather small. After Wilma '05, Maria '17 just prior to landfall in the Puerto Rico is probably the best sampled eyewall replacement similar to this one. Both SFMR data and flight level winds significantly dropped while the outer eyewall transitioned to the primary eyewall. NHC best track doesn't show this change particularly well (partially due to the coarse nature of best track points six hours apart), but the recon data did. I think it's pretty likely that we've dropped all the way down to 130-140 kt from something like 170 kt earlier, with the exact wind dependent on how low the pressure actually dropped.

Not sure how well I said what I wanted to say there, I'm a little scatterbrained today. : P

[Highteeld]

Believe it or not, JTWC might actually be somewhat close to reality in this case. Data from Wilma '05 in particular showed that the max winds can drop considerably at first as core pressure gradient transitions and the outer eyewall begins to take over. That doesn't change the likely considerable underestimation earlier though.

One other question I have is this: does that apply to sfc winds or FL? IIRC, Wilma was before the time of SFMR, so the way we measured that storm may not yield the same results as current protocol. IDK, just thinking out loud... just seems like SFMR and FL winds have a bigger gap during ERC's, while the gap is very small to nil during RI phases (assuming we believe SFMR is a decent benchmark, that is). All anecdotal on my behalf.

Both I think, although the data set is rather small. After Wilma '05, Maria '17 just prior to landfall in the Puerto Rico is probably the best sampled eyewall replacement similar to this one. Both SFMR data and flight level winds significantly dropped while the outer eyewall transitioned to the primary eyewall. NHC best track doesn't show this change particularly well (partially due to the coarse nature of best track points six hours apart), but the recon data did. I think it's pretty likely that we've dropped all the way down to 130-140 kt from something like 170 kt earlier, with the exact wind dependent on how low the pressure actually dropped.

Not sure how well I said what I wanted to say there, I'm a little scatterbrained today. : P

I guess what I'm suggesting is maybe the typical FL to SFC ratio of .85 might more like this: .9 -- 1 to 1 ratio (RI Phase), while a .75 -- .85 FL to SFC ratio (ERC phase) might be accurate. All of this is hard to quantify, though, since as you said, the data set is not large. I think Lorenzo during its first ERC had something like FL of 103 knots with SFMR of 77 knots (not counting high SFMR bias here) to yield a ratio of around ~.75... while Dorian during RI, by contrast, had 161 knots FL, and 177 knot SFMR (reduced to 160 knots due to bias), which would be a much larger ratio, nearly 1 to 1.

[Highteeld]

One other question I have is this: does that apply to sfc winds or FL? IIRC, Wilma was before the time of SFMR, so the way we measured that storm may not yield the same results as current protocol. IDK, just thinking out loud... just seems like SFMR and FL winds have a bigger gap during ERC's, while the gap is very small to nil during RI phases (assuming we believe SFMR is a decent benchmark, that is). All anecdotal on my behalf.

Both I think, although the data set is rather small. After Wilma '05, Maria '17 just prior to landfall in the Puerto Rico is probably the best sampled eyewall replacement similar to this one. Both SFMR data and flight level winds significantly dropped while the outer eyewall transitioned to the primary eyewall. NHC best track doesn't show this change particularly well (partially due to the coarse nature of best track points six hours apart), but the recon data did. I think it's pretty likely that we've dropped all the way down to 130-140 kt from something like 170 kt earlier, with the exact wind dependent on how low the pressure actually dropped.

Not sure how well I said what I wanted to say there, I'm a little scatterbrained today. : P

I guess what I'm suggesting is maybe the typical FL to SFC ratio of .85 might more like this: .9 -- 1 to 1 ratio (RI Phase), while a .75 -- .85 FL to SFC ratio (ERC phase) might be accurate. All of this is hard to quantify, though, since as you said, the data set is not large. I think Lorenzo during its first ERC had something like FL of 103 knots with SFMR of 77 knots (not counting high SFMR bias here) to yield a ratio of around ~.75... while Dorian during RI, by contrast, had 161 knots FL, and 177 knot SFMR (reduced to 160 knots due to bias), which would be a much larger ratio, nearly 1 to 1.

Just to make this more confusing and anecdotal , here are some of Maria's data before landfall (doing an ERC). Note the large gap in FL vs SFMR (~.75 SFMR/FL)

[Highteeld]

Inner eyewall continues to erode:

[Highteeld]

Inner eyewall continues to erode:
https://i.imgur.com/ipsU5S9.png

Last one for a bit:

[Hayabusa]

[Highteeld]

20W HAGIBIS 191008 0600 17.7N 142.6E WPAC 135 920

[Tailspin]

https://imgur.com/vzN2JPm
X- 8hours

[Hayabusa]

6Z GFS is earlier than the usual 930Z start time today.