Discussion of Intense Tropical Cyclones

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Re: Discussion of Intense Tropical Cyclones

#701 Postby Yellow Evan » Wed Dec 22, 2021 1:57 am

Foxfires wrote:
Yellow Evan wrote:For those of you who think Rai’s first peak is a Category 5, I have a challenge. Find me an OW eye Recon-confirmed Category 5 where the eye is well resolved.


OW? what does that stand for?


Off White on the Black Dvorak enhancement scale, representing an eye -30C to 9C.
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Re: Discussion of Intense Tropical Cyclones

#702 Postby Foxfires » Sun Dec 26, 2021 6:23 am

Yellow Evan wrote:For those of you who think Rai’s first peak is a Category 5, I have a challenge. Find me an OW eye Recon-confirmed Category 5 where the eye is well resolved.


I come back here to what is basically the awkward silence for a question that hasn't been answered in days. I mean.. you probably forgot you asked the question in the first place. So I'm going to break the awkward silence by embarrassing myself still not understanding the question. Does well resolved mean well defined? Because I think I can find some category 5s with off-white holes in them. Maybe.

So assuming I'm not understanding the request wrong, here are some attempts. Feel free to correct my idiocy.

Image
There's uh Typhoon Betty 1987. IBTrACS says this was Betty at 11 Aug 15:00 UTC which is 892-891mb. JTWC gives 140kt (yes this is probably AH77 derived).

Image
There's also uh Hurricane Andrew.

Also, this would imply I think Rai reached category 5 first peak.. which I don't actually. It's not because I think it's a category 4 or something, but more like, I don't I'm qualified to give my own estimate.
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Re: Discussion of Intense Tropical Cyclones

#703 Postby Yellow Evan » Sun Dec 26, 2021 11:59 am

Well I didn't expect anyone to even attempt to answer this question so good job! Your answer allows me to answer the question. "Well resolved" is more of a whether a satellite imagery was able to properly resolve the eye temperature. This isn't an issue on the latest generation of current satellites but it has been an issue in the past. Having a not ideal viewing angle (say 35 degrees or so) also further reduces resolution. This tends to be an issue in the the Southwestern Indian Ocean and off the west coast of Mexico (in between the historical position of GOES East and GOES West), although the highest resolution of satellites offsets this. This is why you check polar imagery.

For the examples you named, here's polar for Betty (the three best images I can find):

Image

Image

Image

Definitely not OW there.

For Andrew:

Image

Image

Def WMG at first image (as close to main peak as I can get), and second image isn't of amazing quality and is still barely WMG.

As for the original question, I'm only aware of 2 that even have claims. Opal 1995 (152 FL converts to 137 at sfc which given the 919 pressure, I'm inclined to go 140) and Agnes 1984 (925 mbar pressure supports 140). I guess there's also Matthew but that likely won't be a Category 5 for much longer. You basically need a WMG eye to reach Category 5 status, and most Recon confirmed cases of OW eye embedded in CMG are Category 4's (Eta, Nelson/Pamela 82, Percy 81, Alice 79 good examples of this). Therefore, Rai at first peak was likely Category 4.
Last edited by Yellow Evan on Mon Dec 27, 2021 11:19 pm, edited 1 time in total.
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Re: Discussion of Intense Tropical Cyclones

#704 Postby Foxfires » Mon Dec 27, 2021 10:03 pm

Yellow Evan wrote:Well I didn't expect anyone to even attempt to answer this question so good job! Your answer allows me to answer the question. "Well resolved" is more of a whether a satellite imagery was able to properly resolve the eye temperature. This isn't an issue on the latest generation of current satellites but it has been an issue in the past. Having a not ideal viewing angle (say 35 degrees or so) also further reduces resolution. This tends to be an issue in the the Southwestern Indian Ocean and off the west coast of Mexico (in between the historical position of GOES East and GOES West), although the highest resolution of satellites offsets this. This is why you check polar imagery.

For the examples you named, here's polar for Betty (the three best images I can find):

https://www1.ncdc.noaa.gov/pub/data/satellite/hursat/1987/1987219N08134/AVHRR-IR/1987219N08134.BETTY.1987.08.10.1851.085.NOAA-9.09.AVHRR-IR.png

https://www1.ncdc.noaa.gov/pub/data/satellite/hursat/1987/1987219N08134/AVHRR-IR/1987219N08134.BETTY.1987.08.10.2256.100.NOAA-10.16.AVHRR-IR.png

https://www1.ncdc.noaa.gov/pub/data/satellite/hursat/1987/1987219N08134/AVHRR-IR/1987219N08134.BETTY.1987.08.11.1840.125.NOAA-9.40.AVHRR-IR.png

Definitely not OW there.

For Andrew:

https://www1.ncdc.noaa.gov/pub/data/satellite/hursat/1992/1992230N11325/AVHRR-IR/1992230N11325.ANDREW.1992.08.23.1242.128.NOAA-12.11.AVHRR-IR.png

https://www1.ncdc.noaa.gov/pub/data/satellite/hursat/1992/1992230N11325/AVHRR-IR/1992230N11325.ANDREW.1992.08.24.0925.101.NOAA-11.47.AVHRR-IR.png

Def WMG at first image (as close to main peak as I can get), and second image isn't of amazing quality and is still barely WMG.

As for the original question, I'm only aware of 2 that even have claims. Opal 1995 (152 FL converts to 137 at sfc which given the 919 pressure, I'm inclined to go 140) and Agnes 1984 (925 mbar pressure supports 140). I guess there's also Matthew but that likely won't be a Category 5 for much longer (Eta, Nelson/Pamela 82, Percy 81, Alice 79 good examples of this). You basically need a WMG eye to reach Category 5 status, and most Recon confirmed cases of OW eye embedded in CMG are Category 4's. Therefore, Rai at first peak was likely Category 4.


Ah ok that makes sense, thank you
If you don't mind, could I have a link to the website where you got the polar imagery from?

Edit: Never mind, I'm dumb; forgot I could check the image address.
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Re: Discussion of Intense Tropical Cyclones

#705 Postby Foxfires » Mon Jan 10, 2022 4:07 am

Ok, ok, I kept forgetting to post this and remembering it during inconvenient times.

I remember looking through old Category 6 (blog) articles about Typhoon Haiyan and stuff because I was bored and I came across this one.

https://www.wunderground.com/blog/JeffMasters/super-typhoon-haiyan-storm-surge-survey-finds-high-water-marks-46-feet.html

When I scrolled to the bottom I came across something.

Image

I didn't pay much attention at the time, thinking someone had already done research and stuff with it, and assuming it was probably already debunked because the official pressure hadn't changed, but after looking through a lot of stuff about Haiyan, including stuff here (e.g. stuff about the 860mb estimate) as well as remembering the thing in the first place, I realized, no one has ever mentioned it outside the article that I can see.

And I was wondering: was this verified? was the reading unreliable? did anyone even bother to find out? This is extremely low for a land reading, and impressive especially at that latitude, and it would tie Haiyan with the Labor Day Hurricane for lowest pressure at landfall (though, Meranti might've beaten that by a lot according to an unverified measurement). When I google anything related to Haiyan and 892mb, all I get is that blog post and comparisons to the Labor Day Hurricane. I haven't asked Dr. Jeff Masters about it, so if anyone can do that that'd be great (I've given up using my Twitter account for anything).
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Re: Discussion of Intense Tropical Cyclones

#706 Postby Hurricane2021 » Sat Feb 12, 2022 8:31 pm

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Re: Discussion of Intense Tropical Cyclones

#707 Postby NotoSans » Thu Mar 10, 2022 12:16 pm

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Re: Discussion of Intense Tropical Cyclones

#708 Postby ncforecaster89 » Sun Mar 13, 2022 11:06 pm



Actually, the revised SFMR for Dorian would, in fact, reduce the current 160 kt estimate. The SFMR is the only data supportive of an intensity greater than 145 kt. A blend of the max 700 mb FLW, WL150 winds, and the highest revised SFMR would equate to 153.3 kt or a 155 kt estimate. Slight reduction, but significant as it would drop Dorian below the 1935 Great Labor Day Hurricane for strongest NATL basin landfall, officially.

https://www.nhc.noaa.gov/data/tcr/AL052019_Dorian.pdf
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Re: Discussion of Intense Tropical Cyclones

#709 Postby Yellow Evan » Mon Mar 14, 2022 11:04 am

Dorian had 178 knot SFMR winds. Revised SFMR could still support 165.
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Re: Discussion of Intense Tropical Cyclones

#710 Postby ncforecaster89 » Mon Mar 14, 2022 11:37 am

Yellow Evan wrote:Dorian had 178 knot SFMR winds. Revised SFMR could still support 165.


True, but given the rest of the in-situ data only supporting 145 kt, it’s arguably best to still blend the aforementioned data for a 155 kt estimate.
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Re: Discussion of Intense Tropical Cyclones

#711 Postby Yellow Evan » Mon Mar 14, 2022 12:04 pm

ncforecaster89 wrote:
Yellow Evan wrote:Dorian had 178 knot SFMR winds. Revised SFMR could still support 165.


True, but given the rest of the in-situ data only supporting 145 kt, it’s arguably best to still blend the aforementioned data for a 155 kt estimate.


The FL reduction factor is just an average and can range from .7 to >1.0 so I never really understood the argument for applying much weight towards it when hopefully better methods exist, and the dropsondes are vulnerable to undersampling in a way that SFMR values are not.
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Re: Discussion of Intense Tropical Cyclones

#712 Postby InfernoFlameCat » Mon Mar 14, 2022 2:17 pm

Remember, Dorian was probably more efficient at converting flight lvl winds to surface winds. So the standard .9 conversion doesn’t apply. Therefore an argument could still be made to keep Dorian at 165 knots. Also 178 knots-10 knots is still more than 165 knots so the new change would still support 165 knots when concerning sfmr.
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Re: Discussion of Intense Tropical Cyclones

#713 Postby ncforecaster89 » Mon Mar 14, 2022 7:40 pm

InfernoFlameCat wrote:Remember, Dorian was probably more efficient at converting flight lvl winds to surface winds. So the standard .9 conversion doesn’t apply. Therefore an argument could still be made to keep Dorian at 165 knots. Also 178 knots-10 knots is still more than 165 knots so the new change would still support 165 knots when concerning sfmr.


The SFMR has been far less reliable for providing an intensity estimate in comparison with the 700 mb FLW conversion. Moreover, the WL150 winds corresponded to only 147 kt which counters the argument that Dorian was supposedly “more efficient” in bringing winds to the surface that supports anything higher than 155 kt.

To reiterate, a blend of the data is arguably the best representation of Dorian’s true peak intensity (150-155 kt).
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Re: Discussion of Intense Tropical Cyclones

#714 Postby ncforecaster89 » Mon Mar 14, 2022 7:50 pm

Yellow Evan wrote:
ncforecaster89 wrote:
Yellow Evan wrote:Dorian had 178 knot SFMR winds. Revised SFMR could still support 165.


True, but given the rest of the in-situ data only supporting 145 kt, it’s arguably best to still blend the aforementioned data for a 155 kt estimate.


The FL reduction factor is just an average and can range from .7 to >1.0 so I never really understood the argument for applying much weight towards it when hopefully better methods exist, and the dropsondes are vulnerable to undersampling in a way that SFMR values are not.


The SFMR hasn’t proven to be a better/more accurate method in assessing intensity. In contrast, the 700 mb FLW conversion has historically proven to be a more reliable method, albeit imperfect, to ascertain a storm’s true strength.

As time passes and more data has been obtained and analyzed, the SFMR will likely become consistently more reliable, but it isn’t there yet to stand alone as the be all, end all, in determining a peak intensity estimate.
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Re: Discussion of Intense Tropical Cyclones

#715 Postby Yellow Evan » Mon Mar 14, 2022 9:04 pm

ncforecaster89 wrote:
Yellow Evan wrote:
ncforecaster89 wrote:
True, but given the rest of the in-situ data only supporting 145 kt, it’s arguably best to still blend the aforementioned data for a 155 kt estimate.


The FL reduction factor is just an average and can range from .7 to >1.0 so I never really understood the argument for applying much weight towards it when hopefully better methods exist, and the dropsondes are vulnerable to undersampling in a way that SFMR values are not.


The SFMR hasn’t proven to be a better/more accurate method in assessing intensity. In contrast, the 700 mb FLW conversion has historically proven to be a more reliable method, albeit imperfect, to ascertain a storm’s true strength.

As time passes and more data has been obtained and analyzed, the SFMR will likely become consistently more reliable, but it isn’t there yet to stand alone as the be all, end all, in determining a peak intensity estimate.


The NHC only started full on blending due to uncertainty with the SFMR that arised after 2017, and we don’t always see full on blending at lower intensities. With confidence of the SFMR restored, the urge to constantly blend shouldn’t be applied as universally.
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Re: Discussion of Intense Tropical Cyclones

#716 Postby ncforecaster89 » Tue Mar 15, 2022 1:03 pm

Yellow Evan wrote:
ncforecaster89 wrote:
Yellow Evan wrote:
The FL reduction factor is just an average and can range from .7 to >1.0 so I never really understood the argument for applying much weight towards it when hopefully better methods exist, and the dropsondes are vulnerable to undersampling in a way that SFMR values are not.


The SFMR hasn’t proven to be a better/more accurate method in assessing intensity. In contrast, the 700 mb FLW conversion has historically proven to be a more reliable method, albeit imperfect, to ascertain a storm’s true strength.

As time passes and more data has been obtained and analyzed, the SFMR will likely become consistently more reliable, but it isn’t there yet to stand alone as the be all, end all, in determining a peak intensity estimate.


The NHC only started full on blending due to uncertainty with the SFMR that arised after 2017, and we don’t always see full on blending at lower intensities. With confidence of the SFMR restored, the urge to constantly blend shouldn’t be applied as universally.


I understand your point, but respectfully argue that the revision of the SFMR shouldn’t override the other in-situ data that suggests a different intensity estimate. That’s my reasoning for the blending of the aforementioned data.
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Re: Discussion of Intense Tropical Cyclones

#717 Postby Meteophile » Wed Apr 27, 2022 5:39 pm

One of the worst-looking cyclone damages i've ever seen is the aftermath of Cyclone Harold in pentecost island.
According to World Vision's Vanuatu director Kendra Gates Derousseau, the damages were significantly worse than Pam's.
https://www.rte.ie/news/world/2020/0414 ... d-weather/
"After Pam, people were able to pick up the pieces pretty quickly, put a tarp on the roof and replant the garden. What we're seeing from Harold is that houses have been blown to smithereens, there's nothing to pick up."

The pictures i've seen on the internet seem to go well with this statement (first picture is a before/after comparison).
Image
Image
Image
Image
Pictures from melsisi (town that probably got the worst of the storm) i don't know how many time after the storm.


Satellite animation from cyclone Harold is famous for what seems to be a very rapid reintensification. Maybe the satellite eye's temps were biased by the presence of clouds still in it after such a quick change, leading to an intensity underestimate ?
Image
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Re: Discussion of Intense Tropical Cyclones

#718 Postby CrazyC83 » Wed Apr 27, 2022 8:48 pm

ncforecaster89 wrote:


Actually, the revised SFMR for Dorian would, in fact, reduce the current 160 kt estimate. The SFMR is the only data supportive of an intensity greater than 145 kt. A blend of the max 700 mb FLW, WL150 winds, and the highest revised SFMR would equate to 153.3 kt or a 155 kt estimate. Slight reduction, but significant as it would drop Dorian below the 1935 Great Labor Day Hurricane for strongest NATL basin landfall, officially.

https://www.nhc.noaa.gov/data/tcr/AL052019_Dorian.pdf


150 kt might be the best estimate for Dorian there.
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Re: Discussion of Intense Tropical Cyclones

#719 Postby 115MphAgatha » Wed Jun 01, 2022 3:10 pm

On the topic of the forthcoming SFMR recalibration, here are some storms that might get changes.
Matthew 2016 - Yep, bye bye Category Five. It has exactly one hope of retaining C5 and that is if the SFMR only lowers the winds by 5 knots which isn't likely.
Irma, Jose, Maria 2017 - Actually not sure about these ones. Perhaps Irma goes back to 185? Perhaps it goes down to 175? Even lower? Could Jose be upgraded?
Michael 2018 - Actually it's probably going to stay the same, if not upgraded.
Dorian 2019 - Conflicted on whether it's going to stay the same or get downgraded. An upgrade seems out of the question.
Laura, Eta 2020 - Not sure at all lol can someone explain what the most likely scenario is
Iota 2020 - If you do the normal SMFR reduction reading from the SMFR estimates at peak intensity, which is 6%, you'd still get a category 5. Likely scenario is upgrade back to C5.
Ida, Sam 2021 - Uhh I don't know maybe they each go up 5 knots or something. That said though Sam probably ends up being the same.
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Re: Discussion of Intense Tropical Cyclones

#720 Postby al78 » Wed Jun 01, 2022 3:29 pm

Meteophile wrote:One of the worst-looking cyclone damages i've ever seen is the aftermath of Cyclone Harold in pentecost island.
According to World Vision's Vanuatu director Kendra Gates Derousseau, the damages were significantly worse than Pam's.
https://www.rte.ie/news/world/2020/0414 ... d-weather/
"After Pam, people were able to pick up the pieces pretty quickly, put a tarp on the roof and replant the garden. What we're seeing from Harold is that houses have been blown to smithereens, there's nothing to pick up."


How on earth does anyone recover from that. Some of that damage looks like an atomic bomb went off.
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