2020 TCRs

[galaxy401]

So with the Eta report not published yet, does this mark the first time that there were unreleased TCR reports while the following hurricane season is in progress? I know some of the late reports, like Dorian's, tend to come out by April or May.

[NorthieStangl]

So with the Eta report not published yet, does this mark the first time that there were unreleased TCR reports while the following hurricane season is in progress? I know some of the late reports, like Dorian's, tend to come out by April or May.

I believe so. Not surprising, as 2020 was by a whole mile the most active season ever. The only comparable season was 2005 with 28 storms and the last TCR that season was released on, if I recall correctly, 28 April 2006, although several of those TCRs had been updated since then.

[NorthieStangl]

This change is well within the typical range of uncertainty in NHC’s post-storm intensity
analyses, but the discrepancy between dropsonde-based reductions of peak flight-level winds
and SFMR-derived surface winds leads to greater-than-normal uncertainty in the peak intensity
of Iota, as has been noted in previous intense hurricanes such as Matthew in 2016, Irma, Jose,
and Maria in 2017, and Dorian in 2019. Future adjustments may be needed to Iota’s estimated
peak intensity once SFMR data at high wind speeds are recalibrated.

Maybe we are going to see a reanalysis of recent high-end storms sometime in the future? If they "recalibrate" the SFMR readings it would certainly change some peaks

There is a HURDAT reanalysis project that had been ongoing for the last two decades, without any clarification about when will be the last season they review, so it's very possible that the project will move onto the 2010s and even the 2020s, then we could expect some overdue downgrades and upgrades.

[ncforecaster89]

This change is well within the typical range of uncertainty in NHC’s post-storm intensity
analyses, but the discrepancy between dropsonde-based reductions of peak flight-level winds
and SFMR-derived surface winds leads to greater-than-normal uncertainty in the peak intensity
of Iota, as has been noted in previous intense hurricanes such as Matthew in 2016, Irma, Jose,
and Maria in 2017, and Dorian in 2019. Future adjustments may be needed to Iota’s estimated
peak intensity once SFMR data at high wind speeds are recalibrated.

Maybe we are going to see a reanalysis of recent high-end storms sometime in the future? If they "recalibrate" the SFMR readings it would certainly change some peaks

There is a HURDAT reanalysis project that had been ongoing for the last two decades, without any clarification about when will be the last season they review, so it's very possible that the project will move onto the 2010s and even the 2020s, then we could expect some overdue downgrades and upgrades.

There’s no doubt that quite a few of the storms through the 1990’s will have their intensities amended once the HURDAT reanalysis project ultimately reaches that period. However, it’s highly likely that the NHC will make the necessary changes to the more recent high-end hurricanes (affected by SFMR bias) within the next few years...and not wait until those decades are reached sequentially.

I should note that their preliminary research suggests that the SFMR bias is most influential at intensities exceeding 120 kt.

[ncforecaster89]

NHC seems to have provided a sneak peek for the remaining TCRs in a just-uploaded season summary table:
https://www.nhc.noaa.gov/data/tcr/2020_ ... _Table.pdf

- Eta is bumped up to 135kt, short of a category 5
- Iota is downgraded to 135kt, no longer a category 5
- Zeta remains 95kt, ie no MH
- Laura remains 130kt

Although the NHC did increase Zeta by 5 kt to a peak intensity of 100 kt, this table matches the final decisions on those for Laura and Iota.

I suspect they will also increase Eta to 135 kt. It’s unfortunate that Recon wasn’t able to sample it at peak strength, and as a consequence, I see very little chance the NHC will upgrade Eta by 10 kt to a Cat 5.

[MarioProtVI]

https://www.nhc.noaa.gov/data/tcr/AL292020_Eta.pdf

Eta’s is up. As expected, no C5. Pressure lowered by 1 mb and actually degenerated over the mountains of Nicaragua

[EquusStorm]

[aspen]

https://www.nhc.noaa.gov/data/tcr/AL292020_Eta.pdf

Eta’s is up. As expected, no C5. Pressure lowered by 1 mb and actually degenerated over the mountains of Nicaragua

I would’ve gone several mbar lower due to how pressure was dropping like a rock when recon left.

[EquusStorm]

I think there's little doubt it was stronger and deeper after that plane left, with the NW quad not really being sampled and the second plane breaking though we'll never know for sure. Just thrilled all the TCRs are finally out, missing only one was killing my OCD

[CrazyC83]

The limited amount of data really hurt the analysis of Eta. A case could be made for 135 kt at 06Z (presumably with a pressure around 918 mb) based on extrapolation, but that would be as far as it could go. The next flight around 13Z found a pressure of 936 mb and winds supporting about 120-125 kt. The question is when it began to weaken.

As I thought, the track was also broken up with a remnant low stage as it left Central America. Operationally, it was a tropical depression all the way across, but that was likely generous and indeed it was.

[EquusStorm]

Yeah it definitely makes sense to lower it to remnants there, surface center was really questionable by the time it made it to Honduras. Still the same storm from the mid levels up no doubt but not much left at the surface. Good to keep going operationally of course but likely the right TCR call.

[Stormybajan]

Our Cat 5 streak is officially OVER! Iota will always be one to me, but the lack of recon and data overall has damaged the full extent of Eta's true winds however high they were, we will never know

[aspen]

Our Cat 5 streak is officially OVER! Iota will always be one to me, but the lack of recon and data overall has damaged the full extent of Eta's true winds however high they were, we will never know

If Iota wasn’t a Cat 5, then neither was Matthew, so therefore that record-breaking Cat 5 streak from 2016-20 (now 2016-19 after Iota’s TCR) never existed, and is still tied with the 3-year streak from 2003-05.

[MarioProtVI]

Our Cat 5 streak is officially OVER! Iota will always be one to me, but the lack of recon and data overall has damaged the full extent of Eta's true winds however high they were, we will never know

If Iota wasn’t a Cat 5, then neither was Matthew, so therefore that record-breaking Cat 5 streak from 2016-20 (now 2016-19 after Iota’s TCR) never existed, and is still tied with the 3-year streak from 2003-05.

2017-19 as there’s no evidence IMO to support C5 Matthew.

The limited amount of data really hurt the analysis of Eta. A case could be made for 135 kt at 06Z (presumably with a pressure around 918 mb) based on extrapolation, but that would be as far as it could go. The next flight around 13Z found a pressure of 936 mb and winds supporting about 120-125 kt. The question is when it began to weaken.

As I thought, the track was also broken up with a remnant low stage as it left Central America. Operationally, it was a tropical depression all the way across, but that was likely generous and indeed it was.

I think 130 kt was fair because there was FL of only 137 kt which rounds to 125 kt and blended with the SFMR yields 130 kt.

[AnnularCane]

I think there's little doubt it was stronger and deeper after that plane left, with the NW quad not really being sampled and the second plane breaking though we'll never know for sure. Just thrilled all the TCRs are finally out, missing only one was killing my OCD

I don't think I have OCD, but I always refuse to make a prediction of 20 storms because I feel like going through the whole list except one would drive me crazy.

[EquusStorm]

We do still have a pretty impressive six year 135kt streak going on though, from Joaquin to Iota, so I guess we can hold onto that one if we need to lol

[SconnieCane]

We do still have a pretty impressive six year 135kt streak going on though, from Joaquin to Iota, so I guess we can hold onto that one if we need to lol

130kt+ North Atlantic TCs since 2015:

2015: Joaquin
2016: Matthew
2017: Irma, Jose, Maria
2018: Michael
2019: Dorian, Lorenzo
2020: Laura, Eta, Iota

With in situ, real-time measurements possible in hurricanes in a way that they are not with (the vast majority of) tornadoes, I always assumed that assessing the difference between a Category 4 and 5 hurricane would be much easier to do with high confidence than, say, trying to determine the difference between an EF4 and EF5 tornado based on the construction quality of the strongest building it hit. I guess I didn't appreciate how difficult it is to capture the true peak intensity even with recon and all the various satellite-based tools.

[Teban54]

We do still have a pretty impressive six year 135kt streak going on though, from Joaquin to Iota, so I guess we can hold onto that one if we need to lol

130kt+ North Atlantic TCs since 2015:

2015: Joaquin
2016: Matthew
2017: Irma, Jose, Maria
2018: Michael
2019: Dorian, Lorenzo
2020: Laura, Eta, Iota

With in situ, real-time measurements possible in hurricanes in a way that they are not with (the vast majority of) tornadoes, I always assumed that assessing the difference between a Category 4 and 5 hurricane would be much easier to do with high confidence than, say, trying to determine the difference between an EF4 and EF5 tornado based on the construction quality of the strongest building it hit. I guess I didn't appreciate how difficult it is to capture the true peak intensity even with recon and all the various satellite-based tools.

Florence '18 peaked at 130 kts as well.

[Nuno]

I think there's little doubt it was stronger and deeper after that plane left, with the NW quad not really being sampled and the second plane breaking though we'll never know for sure. Just thrilled all the TCRs are finally out, missing only one was killing my OCD

Did anyone figure out why flight patterns around Eta were so irregular? Or was that Iota?

[Astromanía]

Could they downgraded lorenzo as well, please?