EPAC: OTIS - Aftermath - Discussion

[NDG]

WOW! 205 mph gusts

https://twitter.com/SMareograficoN/status/1719117506999464447

And this was at 10M, those high rise buildings and houses several hundred feet above SL on the hills could had easily seen winds 20-30 mph stronger than at the surface. No wonder those top floors were totally destroyed on some of those buildings.

[cycloneye]

The damage is very extreme in the buildings.

 https://twitter.com/DAGUILARFOTO/status/1719729580905501151

[cycloneye]

Strongest EPAC landfall in the satelite era.

 https://twitter.com/NOAASatellites/status/1720140778524365008

[ljmac75]

https://earthobservatory.nasa.gov/image ... icane-otis

Satellite showing the amount of tree damage in the area. Look at all that brown.

[CrazyC83]

Looking back through additional data, here's a few more thoughts:

* It's becoming clear that Otis made landfall as a category 5 - even if it weakened, that 205 mph wind gust, used at face value in the eyewall, is well supportive of a landfall intensity of 145 kt.
* Otis was likely an INCREDIBLY intense hurricane approaching landfall. I'd be willing to go as high as 160 kt at around 0430Z, but there is no data supporting such. I went with a conservative 150 kt (assuming slight weakening before landfall). That said, it's unclear how much it actually weakened before landfall.
* The pressure was likely VERY high for the intensity. I still think the landfall pressure was around 933 mb (going with the previous calculation and may have overestimated it previously) and haven't seen any evidence supporting a lower pressure. That means I assessed the minimum pressure at 928 mb. It could have been lower - but that is based on the 5 kt decrease. That high pressure is also supported by the Recon flight - at 2030Z, it was likely 115 kt despite a pressure of 960 mb, and at 1900Z, it was likely 105 kt with a pressure of 971 mb.

My revised best track, with new data (again, not official):

EP182023, OTIS, 20,
20231021, 1200, , LO, 9.7N, 97.1W, 25, 1010,
20231021, 1800, , TD, 9.6N, 97.0W, 25, 1010,
20231022, 0000, , TD, 9.5N, 96.8W, 30, 1009,
20231022, 0600, , TD, 9.5N, 96.5W, 30, 1008,
20231022, 1200, , TS, 9.8N, 96.7W, 35, 1007,
20231022, 1800, , TS, 10.1N, 96.9W, 40, 1005,
20231023, 0000, , TS, 10.6N, 97.1W, 40, 1005,
20231023, 0600, , TS, 11.2N, 97.3W, 40, 1005,
20231023, 1200, , TS, 11.7N, 97.5W, 45, 1004,
20231023, 1800, , TS, 12.5N, 97.7W, 45, 1003,
20231024, 0000, , TS, 13.3N, 98.0W, 50, 1002,
20231024, 0600, , TS, 13.8N, 98.5W, 60, 999,
20231024, 1200, , HU, 14.3N, 99.0W, 75, 991,
20231024, 1800, , HU, 14.9N, 99.3W, 100, 974,
20231025, 0000, , HU, 15.7N, 99.6W, 135, 942,
20231025, 0430, I, HU, 16.4N, 99.7W, 150, 928,
20231025, 0600, , HU, 16.7N, 99.7W, 145, 931,
20231025, 0625, L, HU, 16.8N, 99.8W, 145, 933,
20231025, 1200, , TS, 17.9N, 100.5W, 60, 990,
20231025, 1800, , DB, 18.7N, 100.9W, 30, 1005,

[CrabKingMike]

Looking back through additional data, here's a few more thoughts:

* It's becoming clear that Otis made landfall as a category 5 - even if it weakened, that 205 mph wind gust, used at face value in the eyewall, is well supportive of a landfall intensity of 145 kt.
* Otis was likely an INCREDIBLY intense hurricane approaching landfall. I'd be willing to go as high as 160 kt at around 0430Z, but there is no data supporting such. I went with a conservative 150 kt (assuming slight weakening before landfall). That said, it's unclear how much it actually weakened before landfall.
* The pressure was likely VERY high for the intensity. I still think the landfall pressure was around 933 mb (going with the previous calculation and may have overestimated it previously) and haven't seen any evidence supporting a lower pressure. That means I assessed the minimum pressure at 928 mb. It could have been lower - but that is based on the 5 kt decrease. That high pressure is also supported by the Recon flight - at 2030Z, it was likely 115 kt despite a pressure of 960 mb, and at 1900Z, it was likely 105 kt with a pressure of 971 mb.

My revised best track, with new data (again, not official):

EP182023, OTIS, 20,
20231021, 1200, , LO, 9.7N, 97.1W, 25, 1010,
20231021, 1800, , TD, 9.6N, 97.0W, 25, 1010,
20231022, 0000, , TD, 9.5N, 96.8W, 30, 1009,
20231022, 0600, , TD, 9.5N, 96.5W, 30, 1008,
20231022, 1200, , TS, 9.8N, 96.7W, 35, 1007,
20231022, 1800, , TS, 10.1N, 96.9W, 40, 1005,
20231023, 0000, , TS, 10.6N, 97.1W, 40, 1005,
20231023, 0600, , TS, 11.2N, 97.3W, 40, 1005,
20231023, 1200, , TS, 11.7N, 97.5W, 45, 1004,
20231023, 1800, , TS, 12.5N, 97.7W, 45, 1003,
20231024, 0000, , TS, 13.3N, 98.0W, 50, 1002,
20231024, 0600, , TS, 13.8N, 98.5W, 60, 999,
20231024, 1200, , HU, 14.3N, 99.0W, 75, 991,
20231024, 1800, , HU, 14.9N, 99.3W, 100, 974,
20231025, 0000, , HU, 15.7N, 99.6W, 135, 942,
20231025, 0430, I, HU, 16.4N, 99.7W, 150, 928,
20231025, 0600, , HU, 16.7N, 99.7W, 145, 931,
20231025, 0625, L, HU, 16.8N, 99.8W, 145, 933,
20231025, 1200, , TS, 17.9N, 100.5W, 60, 990,
20231025, 1800, , DB, 18.7N, 100.9W, 30, 1005,

Why are we using instantaneous gusts below standard elevation on land to make judgments on maximum one-minute sustained winds at standard elevation?

[ljmac75]

https://yaleclimateconnections.org/2023 ... cane-otis/

Interesting article with a few potential caveats on the gust. I'm not sure how much heavy precipitation affects those wind measurements, and I hope the height of the anemometer is listed somewhere. If it's really only half the standard elevation, that sustained wind is probably higher at 10 meters. Hopefully the full data gets posted at some point, or maybe it is, I can't read Spanish so it's not easy to tell.

[Hurricane2022]

[CrazyC83]

Part of the issue is that there is very little data near the time of landfall. Only one pressure reading and it was peripheral, plus that wind gust reading and damage imagery.

If that 205 mph (181 kt) wind gust was taken at face value, in the right side eyewall, at the standard 10-m elevation, that would fall in the typical NHC gust advisory for 150 kt. It's possible that may have been a mesovortex but it is still supportive of a category 5 hurricane.

This will be one of the more challenging TCR's to write up due to the high uncertainty. It kind of reminded me of Hurricane Felix (2007) which had a very high intensity for its pressure as it was compact, embedded in a ridge and moving at a decent clip.

What would the KZC wind estimate be for a pressure of 933 mb at landfall?

[kevin]

Part of the issue is that there is very little data near the time of landfall. Only one pressure reading and it was peripheral, plus that wind gust reading and damage imagery.

If that 205 mph (181 kt) wind gust was taken at face value, in the right side eyewall, at the standard 10-m elevation, that would fall in the typical NHC gust advisory for 150 kt. It's possible that may have been a mesovortex but it is still supportive of a category 5 hurricane.

This will be one of the more challenging TCR's to write up due to the high uncertainty. It kind of reminded me of Hurricane Felix (2007) which had a very high intensity for its pressure as it was compact, embedded in a ridge and moving at a decent clip.

What would the KZC wind estimate be for a pressure of 933 mb at landfall?

Depends on whether you use the >18N or <18N equation. Peak Otis was around 16.8N so you'd expect to use the <18N equation, but NHC often uses a blend or the >18N equation when a storm gets close to the boundary. The >18N equation is slightly more conservative in general. In the case of Otis the difference is very small (like 1 - 2 kt difference). Using the >18N equation a pressure of 933 mb would correspond to winds of roughly 131 kt.

Personally, I estimate peak intensity to be 150 kt before weakening to 140 kt at landfall. Using KZC and a 50/50 blend of the <18N and >18N equations I'd put peak intensity at 150 kt / 913 mb and landfall at 140 kt / 924 mb.

[CrabKingMike]

Part of the issue is that there is very little data near the time of landfall. Only one pressure reading and it was peripheral, plus that wind gust reading and damage imagery.

If that 205 mph (181 kt) wind gust was taken at face value, in the right side eyewall, at the standard 10-m elevation, that would fall in the typical NHC gust advisory for 150 kt. It's possible that may have been a mesovortex but it is still supportive of a category 5 hurricane.

This will be one of the more challenging TCR's to write up due to the high uncertainty. It kind of reminded me of Hurricane Felix (2007) which had a very high intensity for its pressure as it was compact, embedded in a ridge and moving at a decent clip.

What would the KZC wind estimate be for a pressure of 933 mb at landfall?

How is that supportive though? You still have not given a good reason as to why that gust is useful. C4s have put out such gusts (Gustav 2008). Also, slightly pedantic but 205mph is 178kt not 181.

[ljmac75]

https://www.gaceta.unam.mx/rescata-el-servicio-mareografico-nacional-de-la-unam-valiosos-datos-del-interior-del-huracan-otis/

Article about that station recording those high winds. It says the sustained wind was 1-minute, although I'm relying on automatic translation to read it.

[Hurricane2022]

https://www.gaceta.unam.mx/rescata-el-servicio-mareografico-nacional-de-la-unam-valiosos-datos-del-interior-del-huracan-otis/

Article about that station recording those high winds. It says the sustained wind was 1-minute, although I'm relying on automatic translation to read it.

Winds of almost 185 km/h (115 mph - Cat 3!!), gusts above 200 mph and lowest pressure around 964 mbar. Acapulco was literally held hostage by a monster and merciless hurricane. Unbelievable

[Astromanía]

https://euro.eseuro.com/local/1434943.html
350 deaths!

[Hurricane2022]

https://euro.eseuro.com/local/1434943.html
350 deaths!

Well...with ~350 deaths counted, Otis preliminarily becomes the fifth-deadliest storm in Eastern Pacific history in the modern era, as per Wikipedia.

[Astromanía]

Don't think we will see something like this in a long time, this could be the storm of the decade for sure

[cycloneye]

Oh my, sadly I knew the death count would rise as there were many people missing.

[ljmac75]

Mexican government is still saying 48 apparently. https://yucatan.quadratin.com.mx/nacional/especulacion-cifra-de-350-muertos-por-huracan-otis-gobierno-de-acapulco/

It could be speculation as the article says, but I do wonder if this could be a direct vs indirect deaths type of thing. I don't really know if or how Mexico accounts for those with hurricanes.

[Astromanía]

The goverment have been critized a lot for the numbers they are showing, especially people who lives in Acapulco, just to tell you nor the president nor the governator of the state nor the mayor of Acapulco have been present in the city.

[cycloneye]

Another video taken when Otis made landfall.

https://www.youtube.com/watch?v=P06yFunnX0A