2020 TCRs

[InfernoFlameCat]

I think Hurricane Zeta will be released in the next 5 days. I am going to review the SFR winds and other recon data to see if there is sufficient data to consider this storm a Cat 3

[ncforecaster89]

For me, the TCR on hurricane Zeta is the most anticipated of those remaining to be released. It’s arguably the best candidate for a potential categorical upgrade.

If the NHC ultimately decides to increase the landfall intensity to a 100 kt Cat 3, it will constitute the first Greek-named major hurricane landfall on U.S. shores.

[TorSkk]

For me, the TCR on hurricane Zeta is the most anticipated of those remaining to be released. It’s arguably the best candidate for a potential categorical upgrade.

If the NHC ultimately decides to increase the landfall intensity to a 100 kt Cat 3, it will constitute the first Greek-named major hurricane landfall on U.S. shores.

And probably the last one.

[CrazyC83]

If they downgrade Iota, then they might as well go right back to the 2016 files and downgrade Matthew as well... But maybe it was just a typo because I really don't see how they could downgrade it.

Matthew has a much stronger case for a downgrade. No other data supported cat 5 for that storm (FL->Sfc winds around 120 kt, Dvorak T6.5, pressure 942 mb), while Iota at least has multiple data points that could support it (FL->Sfc winds 132 kt, Dvorak T7.0, pressure 917 mb). 140 kt seems reasonable for Iota, while for Matthew the peak I would lower to 130 kt.

[ncforecaster89]

Based on the chart the NHC released a couple weeks ago with amended intensities for both Eta and Iota, I suspect that they are likely adjusting Iota to a 135 kt Cat 4. Although I’d argue 140 kt is a more reasonable estimate (based on satellite and wind-pressure relationships), I can also understand why they could argue for 135 kt based on the 700 mb FLWs...while excluding the SFMR.

[ncforecaster89]

I read a tweet from Eric Blake a couple weeks ago mentioning that he hopes to complete the Zeta TCR for its release by May 15, but he wasn’t making any promises. As a result, I’ll be surprised if it isn’t released by next weekend.

[ClarCari]

Based on the chart the NHC released a couple weeks ago with amended intensities for both Eta and Iota, I suspect that they are likely adjusting Iota to a 135 kt Cat 4. Although I’d argue 140 kt is a more reasonable estimate (based on satellite and wind-pressure relationships), I can also understand why they could argue for 135 kt based on the 700 mb FLWs...while excluding the SFMR.

The old summary chart was much more likely to be the original intensities from November, where if peak intensities didn’t happen at Normal Advisory times it didn’t show as the “peak”. They might have played around with when Iota’s Category 5 strength occurred.

The NHC never downgrades a full Category since they need absolute proof to upgrade in realtime. They tend to give more leeway in “estimating” a storm’s intensity in real time so long as it isn’t a borderline category. In that case they wait for recon or further satellite estimates to upgrade a category in real time.

Long story short, they would never downgrade a full Category in TCR’s. The either upgrade another Category, or downgrade windspeeds that don’t effect the current Category the storm is, since they tend to do a great job with that in real-time.

[ncforecaster89]

Based on the chart the NHC released a couple weeks ago with amended intensities for both Eta and Iota, I suspect that they are likely adjusting Iota to a 135 kt Cat 4. Although I’d argue 140 kt is a more reasonable estimate (based on satellite and wind-pressure relationships), I can also understand why they could argue for 135 kt based on the 700 mb FLWs...while excluding the SFMR.

The old summary chart was much more likely to be the original intensities from November, where if peak intensities didn’t happen at Normal Advisory times it didn’t show as the “peak”. They might have played around with when Iota’s Category 5 strength occurred.

The NHC never downgrades a full Category since they need absolute proof to upgrade in realtime. They tend to give more leeway in “estimating” a storm’s intensity in real time so long as it isn’t a borderline category. In that case they wait for recon or further satellite estimates to change intensity in real time.

Long story short, they would never downgrade a full Category in TCR’s. The either upgrade another Category, or downgrade windspeeds that don’t effect the current Category the storm is, since they tend to do a great job with that in real-time.

You may well be correct, but aside from the aforementioned chart...the Recon data alone is best supportive of 135 kt when excluding the less reliable SFMR in such extreme winds.

Thus, if you’re indeed correct about the chart (although that theory is bucked by the fact they had Eta listed as 135 kt)...it’s still very possible that they downgrade Iota. That said, I would still argue for a 140 kt estimate.

[ClarCari]

Based on the chart the NHC released a couple weeks ago with amended intensities for both Eta and Iota, I suspect that they are likely adjusting Iota to a 135 kt Cat 4. Although I’d argue 140 kt is a more reasonable estimate (based on satellite and wind-pressure relationships), I can also understand why they could argue for 135 kt based on the 700 mb FLWs...while excluding the SFMR.

The old summary chart was much more likely to be the original intensities from November, where if peak intensities didn’t happen at Normal Advisory times it didn’t show as the “peak”. They might have played around with when Iota’s Category 5 strength occurred.

The NHC never downgrades a full Category since they need absolute proof to upgrade in realtime. They tend to give more leeway in “estimating” a storm’s intensity in real time so long as it isn’t a borderline category. In that case they wait for recon or further satellite estimates to change intensity in real time.

Long story short, they would never downgrade a full Category in TCR’s. The either upgrade another Category, or downgrade windspeeds that don’t effect the current Category the storm is, since they tend to do a great job with that in real-time.

You may well be correct, but aside from the aforementioned chart...the Recon data alone is best supportive of 135 kt when excluding the less reliable SFMR in such extreme winds.

Thus, if you’re indeed correct about the chart (although that theory is bucked by the fact they had Eta listed as 135 kt)...it’s still very possible that they downgrade Iota. That said, I would still argue for a 140 kt estimate.

Not necessarily bucked since it could’ve been a mix of data from complete and incomplete charts that someone at the NHC (maybe a recent hire) crammed together and posted without proper clearance.

Also it’s not clear that SFMR is less reliable in extreme intensities, it’s just more a contingent discussion. So since there has been no true answer as of yet, the NHC downgrading Iota would go against every scientific measurement they had when it was at it’s peak.

[ncforecaster89]

The old summary chart was much more likely to be the original intensities from November, where if peak intensities didn’t happen at Normal Advisory times it didn’t show as the “peak”. They might have played around with when Iota’s Category 5 strength occurred.

The NHC never downgrades a full Category since they need absolute proof to upgrade in realtime. They tend to give more leeway in “estimating” a storm’s intensity in real time so long as it isn’t a borderline category. In that case they wait for recon or further satellite estimates to change intensity in real time.

Long story short, they would never downgrade a full Category in TCR’s. The either upgrade another Category, or downgrade windspeeds that don’t effect the current Category the storm is, since they tend to do a great job with that in real-time.

You may well be correct, but aside from the aforementioned chart...the Recon data alone is best supportive of 135 kt when excluding the less reliable SFMR in such extreme winds.

Thus, if you’re indeed correct about the chart (although that theory is bucked by the fact they had Eta listed as 135 kt)...it’s still very possible that they downgrade Iota. That said, I would still argue for a 140 kt estimate.

Not necessarily bucked since it could’ve been a mix of data from complete and incomplete charts that someone at the NHC (maybe a recent hire) crammed together and posted without proper clearance.

Also it’s not clear that SFMR is less reliable in extreme intensities, it’s just more a contingent discussion. So since there has been no true answer as of yet, the NHC downgrading Iota would go against every scientific measurement they had when it was at it’s peak.

Regarding the aforementioned chart, we are each speculating on why the intensities for both Eta and Iota were modified from their respective operational intensities; only they know the real reason.

Although you’re correct that the research is still ongoing for the reliability of the SFMR in extreme wind environments, they have repeatedly made references to the apparent discrepancies that have been occurring between adjusted FL to surface winds and SFMR at intensities of 120 kt or greater. Given that, and my own educated opinion, I surmise that they are likely to place less weight on the SFMR at such extreme velocities. This has been the most recent practice they have employed in such scenarios since 2017.

Consequently, I won’t be surprised if they downgrade Iota to 135 kt or retain the operational 140 kt Cat 5 designation. Being that I personally favor leaning towards the higher estimate in such cases (taking into account undersampling issues), I would go with 140 kt for its peak. I think it’s important to remember that this isn’t an exact science, and concurrently, that there’s a level of subjectivity involved, as a result.

[ClarCari]

You may well be correct, but aside from the aforementioned chart...the Recon data alone is best supportive of 135 kt when excluding the less reliable SFMR in such extreme winds.

Thus, if you’re indeed correct about the chart (although that theory is bucked by the fact they had Eta listed as 135 kt)...it’s still very possible that they downgrade Iota. That said, I would still argue for a 140 kt estimate.

Not necessarily bucked since it could’ve been a mix of data from complete and incomplete charts that someone at the NHC (maybe a recent hire) crammed together and posted without proper clearance.

Also it’s not clear that SFMR is less reliable in extreme intensities, it’s just more a contingent discussion. So since there has been no true answer as of yet, the NHC downgrading Iota would go against every scientific measurement they had when it was at it’s peak.

Regarding the aforementioned chart, we are each speculating on why the intensities for both Eta and Iota were modified from their respective operational intensities; only they know the real reason.

Although you’re correct that the research is still ongoing for the reliability of the SFMR in extreme wind environments, they have repeatedly made references to the apparent discrepancies that have been occurring between adjusted FL to surface winds and SFMR at intensities of 120 kt or greater. Given that, and my own educated opinion, I surmise that they are likely to place less weight on the SFMR at such extreme velocities. This has been the most recent practice they have employed in such scenarios since 2017.

Consequently, I won’t be surprised if they downgrade Iota to 135 kt or retain the operational 140 kt Cat 5 designation. Being that I personally favor leaning towards the higher estimate in such cases (taking into account undersampling issues), I would go with 140 kt for its peak. I think it’s important to remember that this isn’t an exact science, and concurrently, that there’s a level of subjectivity involved, as a result.

I see your points and it’s definitely and ongoing and interesting discussion.

I do have to add that if the intensities end up being the exact same as that premature summary table was, that would mean the Official National Hurricane Center lied on their official account. Not at all saying they are a pop-culture and “always has to be right” type of organization, but it would be honestly callous to later tell followers that the intensities on that table were correct despite them earlier saying they weren’t (and they did it in parenthesis in that tweet for extra emphasis on that point). They would lose so much scientific credibility that, especially in our political climate, they cannot afford to lose. There is ZERO chance they keep all those intensities (one or two of them may end up being correct, but they definitely will keep Iota a Category 5).

[Shell Mound]

Based on the chart the NHC released a couple weeks ago with amended intensities for both Eta and Iota, I suspect that they are likely adjusting Iota to a 135 kt Cat 4. Although I’d argue 140 kt is a more reasonable estimate (based on satellite and wind-pressure relationships), I can also understand why they could argue for 135 kt based on the 700 mb FLWs...while excluding the SFMR.

The old summary chart was much more likely to be the original intensities from November, where if peak intensities didn’t happen at Normal Advisory times it didn’t show as the “peak”. They might have played around with when Iota’s Category 5 strength occurred.

The NHC never downgrades a full Category since they need absolute proof to upgrade in realtime. They tend to give more leeway in “estimating” a storm’s intensity in real time so long as it isn’t a borderline category. In that case they wait for recon or further satellite estimates to change intensity in real time.

Long story short, they would never downgrade a full Category in TCR’s. The either upgrade another Category, or downgrade windspeeds that don’t effect the current Category the storm is, since they tend to do a great job with that in real-time.

You may well be correct, but aside from the aforementioned chart...the Recon data alone is best supportive of 135 kt when excluding the less reliable SFMR in such extreme winds.

Thus, if you’re indeed correct about the chart (although that theory is bucked by the fact they had Eta listed as 135 kt)...it’s still very possible that they downgrade Iota. That said, I would still argue for a 140 kt estimate.

If they downgrade Iota, then they should definitely downgrade Matthew (2016), since reconnaissance, excluding SFMR, supported 130 kt at best.

[InfernoFlameCat]

I think if Iota was downgraded to a cat 4, then Matthew, Michael, and Lorenzo should too. I say this because Iota was definitely a cat 5 so if it is downgraded, why would the other storms still be kept at a Cat 5, especially Matthew and Lorenzo.

[Iceresistance]

I think if Iota was downgraded to a cat 4, then Matthew, Michael, and Lorenzo should too. I say this because Iota was definitely a cat 5 so if it is downgraded, why would the other storms still be kept at a Cat 5, especially Matthew and Lorenzo.

Why Michael? It was operationally a CAT 4 until surveys showed CAT 5 damage & storm Structure at landfall in Panama City, FL . . .

The 2019 TCR on Lorenzo kept as a CAT 5 for Recon evidence . . .

[InfernoFlameCat]

I think if Iota was downgraded to a cat 4, then Matthew, Michael, and Lorenzo should too. I say this because Iota was definitely a cat 5 so if it is downgraded, why would the other storms still be kept at a Cat 5, especially Matthew and Lorenzo.

Why Michael? It was operationally a CAT 4 until surveys showed CAT 5 damage & storm Structure at landfall in Panama City, FL . . .

The 2019 TCR on Lorenzo kept as a CAT 5 for Recon evidence . . .

I am saying that if Iota is downgraded, lets scrap all 140 knot evidence from our low end cat 5s

[TorSkk]

I think if Iota was downgraded to a cat 4, then Matthew, Michael, and Lorenzo should too. I say this because Iota was definitely a cat 5 so if it is downgraded, why would the other storms still be kept at a Cat 5, especially Matthew and Lorenzo.

Lorenzo's peak was based on satellite estimates, it's a different story

[InfernoFlameCat]

I think if Iota was downgraded to a cat 4, then Matthew, Michael, and Lorenzo should too. I say this because Iota was definitely a cat 5 so if it is downgraded, why would the other storms still be kept at a Cat 5, especially Matthew and Lorenzo.

Lorenzo's peak was based on satellite estimates, it's a different story

True. Anyhow my case is a 95% chance that Iota does not get downgraded. The reason I do not say 100% is if somehow they do actually lower the intensity and which in that case I become as grumpy as Wxman57

[Shell Mound]

I think if Iota was downgraded to a cat 4, then Matthew, Michael, and Lorenzo should too. I say this because Iota was definitely a cat 5 so if it is downgraded, why would the other storms still be kept at a Cat 5, especially Matthew and Lorenzo.

Michael’s estimated peak intensity of 140 kt was well supported by peak flight-level winds, NEXRAD-derived velocities, surface observations, and the consensus of various satellite estimates (SATCON). In particular, reconnaissance registered 700-mb winds of 152 kt in the southeastern quadrant, shortly after the RMW moved ashore over Mexico Beach, FL. Given that these MSW translate to 137 kt at the standard 10-m elevation, along with the fact that the peak radar velocities and implied strongest surface winds had already moved inland, this would strongly suggest that at least a small area of 140-kt or even 145-kt winds existed. NEXRAD data also accurately indicated FL winds in the vicinity of the aircraft, with radar estimates suggesting 155 kt at the location of the 152-kt observation by reconnaissance. NEXRAD estimates also suggested 10-m winds of 145–149 kt at the time of landfall. Additionally, MSLP observations from both aircraft and storm chasers indicate that Michael was deepening up to and even shortly after landfall, like Andrew (1992), and that the actual MSLP at landfall was likely on the order of ~916–18 mb. SATCON also supported low-end Category-5 status at landfall, though microwave estimates lagged behind those of other techniques, but the latter should be discarded in favour of hard data from aircraft, NEXRAD, and land-based stations, including mobile storm-chaser networks, all of which solidly support winds of 140–145 kt at landfall. One could even make the case for 150 kt at landfall, though this is less likely than 145 kt.

As for Lorenzo, even though its estimated peak is based on short-term SATCON—that is, closer to hourly than six-hourly increments—the very cold and symmetric CDO, given its relatively high latitude in late September, probably is sufficient to support the NHC’s estimated MSW of 140 kt, despite the eye being relatively large and cool. Additionally, aircraft observations after Lorenzo had weakened reported higher FL winds than would have been expected, given the system’s large size and ongoing filling rate. While AMSUB’s microwave-based estimates indicated a lower MSW than 140 kt, for some reason it was likely underestimating Lorenzo’s actual strength, and the finalised SATCON estimates were lowered only due to constraints.

By contrast, SFMR was the only basis for Matthew’s Cat-5 status. All other data, from aircraft to satellite, supported 130 kt at most.

[InfernoFlameCat]

I think if Iota was downgraded to a cat 4, then Matthew, Michael, and Lorenzo should too. I say this because Iota was definitely a cat 5 so if it is downgraded, why would the other storms still be kept at a Cat 5, especially Matthew and Lorenzo.

Michael’s estimated peak intensity of 140 kt was well supported by peak flight-level winds, NEXRAD-derived velocities, surface observations, and the consensus of various satellite estimates (SATCON). In particular, reconnaissance registered 700-mb winds of 152 kt in the southeastern quadrant, shortly after the RMW moved ashore over Mexico Beach, FL. Given that these MSW translate to 137 kt at the standard 10-m elevation, along with the fact that the peak radar velocities and implied strongest surface winds had already moved inland, this would strongly suggest that at least a small area of 140-kt or even 145-kt winds existed. NEXRAD data also accurately indicated FL winds in the vicinity of the aircraft, with radar estimates suggesting 155 kt at the location of the 152-kt observation by reconnaissance. NEXRAD estimates also suggested 10-m winds of 145–149 kt at the time of landfall. Additionally, MSLP observations from both aircraft and storm chasers indicate that Michael was deepening up to and even shortly after landfall, like Andrew (1992), and that the actual MSLP at landfall was likely on the order of ~916–18 mb. SATCON also supported low-end Category-5 status at landfall, though microwave estimates lagged behind those of other techniques, but the latter should be discarded in favour of hard data from aircraft, NEXRAD, and land-based stations, including mobile storm-chaser networks, all of which solidly support winds of 140–145 kt at landfall. One could even make the case for 150 kt at landfall, though this is less likely than 145 kt.

As for Lorenzo, even though its estimated peak is based on short-term SATCON—that is, closer to hourly than six-hourly increments—the very cold and symmetric CDO, given its relatively high latitude in late September, probably is sufficient to support the NHC’s estimated MSW of 140 kt, despite the eye being relatively large and cool. Additionally, aircraft observations after Lorenzo had weakened reported higher FL winds than would have been expected, given the system’s large size and ongoing filling rate. While AMSUB’s microwave-based estimates indicated a lower MSW than 140 kt, for some reason it was likely underestimating Lorenzo’s actual strength, and the finalised SATCON estimates were lowered only due to constraints.

By contrast, SFMR was the only basis for Matthew’s Cat-5 status. All other data, from aircraft to satellite, supported 130 kt at most.

Exactly my point, Iota deserves Cat 5 just like any of these other storms except maybe matthew.

[TorSkk]

Zeta upgraded to a major hurricane at landfall

https://www.nhc.noaa.gov/data/tcr/AL282020_Zeta.pdf