2020 Atlantic Post-Season Changes

[Hypercane_Kyle]

I honestly didn't see much compelling evidence to support an upgrade to Eta to a Cat 5. Zeta is the only system that deserves an upgrade.

There is some, but it’s mainly assumptions and extrapolations based on what was observed by the final recon plane that actually made it to Eta. If that 4 mb/hr deepening rate continued for 3 hours, leading up to when the EWRC finally began to degrade the pinhole, then Eta could’ve bottomed out as low as 910 mbar. The only direct observations supporting an intensity greater than 130 kt are a single 135 kt SFMR reading and a 155 kt dropsonde, both in the southern half of the storm. Since the northern half and likely the NW quadrant are usually stronger, it can be inferred that perhaps there were sustained Cat 5 winds in the unsampled quadrant.

At the very least, Eta’s pressure should be lowered by a couple of mbar.

I've never seen the NHC upgrade a storm post-season to Category 5 without direct surface observations. Eta was clearly going through an EWRC all of last night, which prevented the inner eyewall from really ramping up. This was enough to prevent it from becoming a Category 5.

[aspen]

When recon leaves a rapidly deepening 130kt storm with pressure tanking and there are no measurements for hours, it's easily assumed 140kt would follow very shortly thereafter. That said, for absolutely no apparent reason they didn't use that logic on Jose in 2017 so I kinda doubt Eta gets its objectively deserved upgrade just based on that precedent. Filing it away 1s 140-150kt personally; just don't have recon data when it mattered most.

We wouldn’t be having this conversation if the other AF plane didn’t have to turn back. It would’ve arrived at just the right time to observe the true peak. Why did the strongest storm of the season have to get the worst recon luck of all time?

[Blinhart]

When recon leaves a rapidly deepening 130kt storm with pressure tanking and there are no measurements for hours, it's easily assumed 140kt would follow very shortly thereafter. That said, for absolutely no apparent reason they didn't use that logic on Jose in 2017 so I kinda doubt Eta gets its objectively deserved upgrade just based on that precedent. Filing it away 1s 140-150kt personally; just don't have recon data when it mattered most.

We wouldn’t be having this conversation if the other AF plane didn’t have to turn back. It would’ve arrived at just the right time to observe the true peak. Why did the strongest storm of the season have to get the worst recon luck of all time?

Yeah I think in post season they will up it to a Cat 5.

[CrazyC83]

As far as Eta, my guess for peak intensity is either 135 or 140 kt and that would be at 06Z. That would depend on whether the 135 kt SFMR (at about 04Z) was legitimate or not. If so, then 140 seems reasonable as it deepened for a couple more hours. My estimate for the lowest pressure is 919 mb based on interpolation afterward.

[Chris90]

Does anyone know if the recon planes’ radar also does velocity scans like nexrad? If they weren’t able to fly through the stronger portions of Eta’s eyewall due to severe turbulence from mesovortices, is there a chance they got velocity data from the radar perhaps? If the NHC has data like that to work with, it might increase the chances for an upgrade. I know velocity data from radar played a big role in Michael’s upgrade. Regardless, I think the 155kts measured at the surface from dropsonde is enough to support 140kts. I think there’s a chance it was a 150-155kt hurricane, it was just too dangerous for recon to sample that portion of the eyewall.

[ClarCari]

Can we please start posting in this thread instead of creating dozens of different threads discussing changes to individual storms?!

Eta has two threads essentially asking the same exact question of how strong it got....

I hope Admin could help close and merge other threads to make this whole forum less cluttered.

As for my post-season opinions in a nutshell:

Gonzalo I doubt gets an upgrade to hurricane.

Laura won’t get the Cat.5 upgrade. I’m not sure if her windspeeds will get an upgrade either.

Marco had data supporting a hurricane so he stays one.

Nana less so but the NHC is not likely to downgrade to TS and I doubt many would look into it all that much.

Paulette stays a Cat.2.

Sally has some data supportive of low-end Cat.3, but the most damning data that could push the NHC to upgrade were some of the wind damage in those areas. While the NHC doesn’t directly Categorize by damage per se, during a debate on razor’s edge of upgrading, the damage could definitely be used as supportive data.

Gamma will probably get an upgrade accounting for no recon at landfall.

Zeta had wind data supportive of Cat.3 in places, but the rather strong gusts and wind damage for a usual Cat.2 may again be used as supportive data on whether to upgrade or not.

Eta will likely be upgraded to Cat.5 after recon left, but low-end. The reason they have a hard time pulling triggers for situations like these is they don’t want a operational Cat.5 making landfall only for there to be sayy...Cat.3 winds reported, as it would make the NHC look somewhat odd to countries that rely on accurate forecasts. However, since Eta went through an EWRC before landfall, the NHC could upgrade Eta to a brief 5, and then the EWRC would be what knocked it to Cat.4 upon landfall without being inconsistent.

[ElectricStorm]

Can we please start posting in this thread instead of creating dozens of different threads discussing changes to individual storms?!

Eta has two threads essentially asking the same exact question of how strong it got....

I hope Admin could help close and merge other threads to make this whole forum less cluttered.

As for my post-season opinions in a nutshell:

Gonzalo I doubt gets an upgrade to hurricane.

Laura won’t get the Cat.5 upgrade. I’m not sure if her windspeeds will get an upgrade either.

Marco had data supporting a hurricane so he stays one.

Nana less so but the NHC is not likely to downgrade to TS and I doubt many would look into it all that much.

Paulette stays a Cat.2.

Sally has some data supportive of low-end Cat.3, but the most damning data that could push the NHC to upgrade were some of the wind damage in those areas. While the NHC doesn’t directly Categorize by damage per se, during a debate on razor’s edge of upgrading, the damage could definitely be used as supportive data.

Gamma will probably get an upgrade accounting for no recon at landfall.

Zeta had wind data supportive of Cat.3 in places, but the rather strong gusts and wind damage for a usual Cat.2 may again be used as supportive data on whether to upgrade or not.

Eta will likely be upgraded to Cat.5 after recon left, but low-end. The reason they have a hard time pulling triggers for situations like these is they don’t want a operational Cat.5 making landfall only for there to be sayy...Cat.3 winds reported, as it would make the NHC look somewhat odd to countries that rely on accurate forecasts. However, since Eta went through an EWRC before landfall, the NHC could upgrade Eta to a brief 5, and then the EWRC would be what knocked it to Cat.4 upon landfall without being inconsistent.

Yeah I agree with these. Sally likely won't get upgraded now that Zeta happened. Zeta had more evidence for Cat 3 than Sally did. I'll be surprised if they don't upgrade Gamma and Zeta. Eta could go either way but I think they should upgrade it because it was very likely a 5.

[Shell Mound]

Marco: 65 → 60 kt
Nana: 65 → 55 kt
Paulette: 90 → 95 kt
Sally: 90 → 95 kt
Teddy: 120 → 115 kt
Gamma: 60 → 75 kt
Delta: 125 → 115 kt
Epsilon: 100 → 105 kt
Zeta: 95 → 100 kt
Eta: 130 → 140 kt

No other changes to the remaining systems

Update

[ncforecaster89]

In my own personal opinion, and estimation, the NHC should either upgrade both Sally and Zeta to 100 kt Cat 3 or have both listed as a 95 kt Cat 2. Based on all the available data, it’s highly unlikely that Zeta possessed winds any stronger than Sally, at their respective landfalls.

[ncforecaster89]

Zeta was almost certainly a major hurricane at landfall, IMO. 130mph+ wind gusts recorded over Port Fourchon, LA, dropsonde gusts >115 knots, flight level winds of >115 knots, radar data of >100 knots, plus whatever data comes out. SFMR at one point even had 105 knot winds, but they were flagged. I'm sure the NHC will review all that data, including the suspect SFMR readings, and make their judgement accordingly, but I strongly believe this was a major hurricane.

Gamma and Zeta are locks for upgrades in my book. Sally and TD 10 are possibilities. I don't really see anything else being upgraded besides small tweaks in windspeed here and there, but no category changes. I wouldn't be shocked to see Nana downgraded but I doubt they do it

Sally seems unlikely, there's very little evidence when compared to Zeta.

Gamma, maybe. I've never seen then upgrade a tropical depression post-season though.

Hi Kyle! I respectfully disagree that Zeta had winds any stronger than Sally at landfall.

Sally:

Highest FL Winds: 110 kt (90% reduction)
Lowest Pressure: 965 mb
Highest Radar Velocities: 122 kt (850 mb)
Satellite Intensity Estimate: T5.5
Highest Measured 10m Gust: 123 mph
Wind Damage: Consistent with 95-100 kt

Zeta:

Highest FL Winds: 119 kt (85% reduction)
Lowest Pressure: 970 mb
Highest Radar Velocities: 126 kt (700 mb)
Satellite Intensity Estimate: T5.5
Highest Measured Gust: 110 mph (6.1m)
Wind Damage: Consistent with 95-100 kt

Comparing the two, they are pretty much equal in terms of their respective landfall intensities, based on a combination of all the aforementioned data. I didn’t list the SFMR measurements as those were likely contaminated by shoaling. Even so, the unflagged readings were essentially the same there, as well. One could make the case that Zeta has a slightly better case for a 100 kt Cat 3 landfall estimate, but not enough to differentiate it from Sally. Although there was an unofficial report regarding a wind gust measurement of 130 mph at Port Fourchon, it isn’t listed in the Slidell/New Orleans NWS post-storm report. Even if it’s a legitimate reading, I believe I read it was recorded on a boat, whereby it’d be very important to know the height from which it was captured; as it was likely elevated.

In short, a combination of all available data suggests hurricane Sally and Zeta struck the U.S. coastline at essentially the same intensity. Therefore, I believe both should be listed as either a 95 kt Cat 2 or a 100 kt Cat 3.

[ClarCari]

I forgot in my earlier post to mention TD 10.

It very likely will be upgraded to a TS since the NHC practically said it out loud in one of their advisories for it. They of course at that time couldn’t outright state that it was since they have a protocol for releasing TCR’s and post-upgrading systems, but the fact that they said it “possibly” have been a TS basically is the same thing as saying “it was a TS, we just have to review it for post-season to finalize”. They rarely suggest a possibility a system was stronger before an advisory unless they actually believe it.

If it is upgraded, this could possibly make July 2020 the most active with 6 named storms depending on when they would list this as a TS.

As well if this get’s upgraded, if every system from now keeps becoming a named storm this year, this would also add 2020 as one of the few years every tropical cyclone becomes a named system. Which would be exceptional for a season especially this busy. Even 2005 had 3 unnamed depressions.

[kevin]

I guess they will keep Eta's restrenghtening into a cat 1 off the coast of Florida, but they'll move it further back in the timeframe. I'm pretty sure Eta was back to a hurricane at least a few hours before the NHC called it one and it also stopped being one before the NHC officially downgraded it to a TS again.

[Ubuntwo]

Gamma and Zeta are locks for upgrades in my book. Sally and TD 10 are possibilities. I don't really see anything else being upgraded besides small tweaks in windspeed here and there, but no category changes. I wouldn't be shocked to see Nana downgraded but I doubt they do it

Sally seems unlikely, there's very little evidence when compared to Zeta.

Gamma, maybe. I've never seen then upgrade a tropical depression post-season though.

Hi Kyle! I respectfully disagree that Zeta had winds any stronger than Zeta at landfall.

Sally:

Highest FL Winds: 110 kt (90% reduction)
Lowest Pressure: 965 mb
Highest Radar Velocities: 122 kt (850 mb)
Satellite Intensity Estimate: T5.5
Highest Measured 10m Gust: 123 mph
Wind Damage: Consistent with 95-100 kt

Zeta:

Highest FL Winds: 119 kt (85% reduction)
Lowest Pressure: 970 mb
Highest Radar Velocities: 126 kt (700 mb)
Satellite Intensity Estimate: T5.5
Highest Measured Gust: 110 mph (6.1m)
Wind Damage: Consistent with 95-100 kt

Comparing the two, they are pretty much equal in terms of their respective landfall intensities, based on a combination of all the aforementioned data. I didn’t list the SFMR measurements as those were likely contaminated by shoaling. Even so, the unflagged readings were essentially the same there, as well. One could make the case that Zeta has a slightly better case for a 100 kt Cat 3 landfall estimate, but not enough to differentiate it from Sally. Although there was an unofficial report regarding a wind gust measurement of 130 mph at Port Fourchon, it isn’t listed in the Slidell/New Orleans NWS post-storm report. Even if it’s a legitimate reading, I believe I read it was recorded on a boat, whereby it’d be very important to know the height from which it was captured; as it was likely elevated.

In short, a combination of all available data suggests hurricane Sally and Zeta struck the U.S. coastline at essentially the same intensity. Therefore, I believe both should be listed as either a 95 kt Cat 2 or a 100 kt Cat 3.

While I don't think any will be upgraded, I'd say Sally has a slightly better chance of being a cat 3 at landfall, with Zeta perhaps peaking at that intensity and weakening just before LF. Sally had consistently higher SFMR that held up (Zeta did have sampling issues). Sally also had legit 10m cat 2 sustained obs, and the footage out of AL was downright impressive.

[ElectricStorm]

Gamma and Zeta are locks for upgrades in my book. Sally and TD 10 are possibilities. I don't really see anything else being upgraded besides small tweaks in windspeed here and there, but no category changes. I wouldn't be shocked to see Nana downgraded but I doubt they do it

Sally seems unlikely, there's very little evidence when compared to Zeta.

Gamma, maybe. I've never seen then upgrade a tropical depression post-season though.

Hi Kyle! I respectfully disagree that Zeta had winds any stronger than Zeta at landfall.

Sally:

Highest FL Winds: 110 kt (90% reduction)
Lowest Pressure: 965 mb
Highest Radar Velocities: 122 kt (850 mb)
Satellite Intensity Estimate: T5.5
Highest Measured 10m Gust: 123 mph
Wind Damage: Consistent with 95-100 kt

Zeta:

Highest FL Winds: 119 kt (85% reduction)
Lowest Pressure: 970 mb
Highest Radar Velocities: 126 kt (700 mb)
Satellite Intensity Estimate: T5.5
Highest Measured Gust: 110 mph (6.1m)
Wind Damage: Consistent with 95-100 kt

Comparing the two, they are pretty much equal in terms of their respective landfall intensities, based on a combination of all the aforementioned data. I didn’t list the SFMR measurements as those were likely contaminated by shoaling. Even so, the unflagged readings were essentially the same there, as well. One could make the case that Zeta has a slightly better case for a 100 kt Cat 3 landfall estimate, but not enough to differentiate it from Sally. Although there was an unofficial report regarding a wind gust measurement of 130 mph at Port Fourchon, it isn’t listed in the Slidell/New Orleans NWS post-storm report. Even if it’s a legitimate reading, I believe I read it was recorded on a boat, whereby it’d be very important to know the height from which it was captured; as it was likely elevated.

In short, a combination of all available data suggests hurricane Sally and Zeta struck the U.S. coastline at essentially the same intensity. Therefore, I believe both should be listed as either a 95 kt Cat 2 or a 100 kt Cat 3.

Well I think Zeta peaked as a Cat 3 then weakened to Cat 2 at landfall. I personally think they should have Sally at 95kts Cat 2 at peak and landfall, and Zeta at 100kts Cat 3 peak with a 95kt Cat 2 landfall.

[CrazyC83]

Sally seems unlikely, there's very little evidence when compared to Zeta.

Gamma, maybe. I've never seen then upgrade a tropical depression post-season though.

Hi Kyle! I respectfully disagree that Zeta had winds any stronger than Zeta at landfall.

Sally:

Highest FL Winds: 110 kt (90% reduction)
Lowest Pressure: 965 mb
Highest Radar Velocities: 122 kt (850 mb)
Satellite Intensity Estimate: T5.5
Highest Measured 10m Gust: 123 mph
Wind Damage: Consistent with 95-100 kt

Zeta:

Highest FL Winds: 119 kt (85% reduction)
Lowest Pressure: 970 mb
Highest Radar Velocities: 126 kt (700 mb)
Satellite Intensity Estimate: T5.5
Highest Measured Gust: 110 mph (6.1m)
Wind Damage: Consistent with 95-100 kt

Comparing the two, they are pretty much equal in terms of their respective landfall intensities, based on a combination of all the aforementioned data. I didn’t list the SFMR measurements as those were likely contaminated by shoaling. Even so, the unflagged readings were essentially the same there, as well. One could make the case that Zeta has a slightly better case for a 100 kt Cat 3 landfall estimate, but not enough to differentiate it from Sally. Although there was an unofficial report regarding a wind gust measurement of 130 mph at Port Fourchon, it isn’t listed in the Slidell/New Orleans NWS post-storm report. Even if it’s a legitimate reading, I believe I read it was recorded on a boat, whereby it’d be very important to know the height from which it was captured; as it was likely elevated.

In short, a combination of all available data suggests hurricane Sally and Zeta struck the U.S. coastline at essentially the same intensity. Therefore, I believe both should be listed as either a 95 kt Cat 2 or a 100 kt Cat 3.

Well I think Zeta peaked as a Cat 3 then weakened to Cat 2 at landfall. I personally think they should have Sally at 95kts Cat 2 at peak and landfall, and Zeta at 100kts Cat 3 peak with a 95kt Cat 2 landfall.

I'd put them almost on even terms. I estimate both were 95 kt at landfall.

[Shell Mound]

Marco: 65 → 60 kt
Nana: 65 → 55 kt
Paulette: 90 → 95 kt
Sally: 90 → 95 kt
Teddy: 120 → 115 kt
Gamma: 60 → 75 kt
Delta: 125 → 115 kt
Epsilon: 100 → 105 kt
Zeta: 95 → 100 kt
Eta: 130 → 150 kt

No other changes to the remaining systems

Update

Eta at 130 knots:


Iota at 140 knots:


Since Eta was clearly more organised at its peak than Iota currently is as a low-end Cat-5, Eta was almost certainly stronger than 140 knots.

[aspen]

Marco: 65 → 60 kt
Nana: 65 → 55 kt
Paulette: 90 → 95 kt
Sally: 90 → 95 kt
Teddy: 120 → 115 kt
Gamma: 60 → 75 kt
Delta: 125 → 115 kt
Epsilon: 100 → 105 kt
Zeta: 95 → 100 kt
Eta: 130 → 150 kt

No other changes to the remaining systems

Update

Eta at 130 knots:
https://upload.wikimedia.org/wikipedia/commons/thumb/1/1e/Eta_2020-11-03_0350Z.jpg/1280px-Eta_2020-11-03_0350Z.jpg

Iota at 140 knots:
https://i.imgur.com/8BgwiJP.png

Since Eta was clearly more organised at its peak than Iota currently is as a low-end Cat-5, Eta was almost certainly stronger than 140 knots.

I do think Iota could help Eta get upgraded, but not because of satellite estimates. The previous recon mission into Iota found Cat 5 winds in the NW quadrant, the one part that wasn’t sampled during Eta’s peak, and since the NW quad is expected to be the strongest for these kinds of westward moving systems, it’s reasonable Eta had >140 kt winds in that quad.

[Shell Mound]

Update

Eta at 130 knots:
https://upload.wikimedia.org/wikipedia/commons/thumb/1/1e/Eta_2020-11-03_0350Z.jpg/1280px-Eta_2020-11-03_0350Z.jpg

Iota at 140 knots:
https://i.imgur.com/8BgwiJP.png

Since Eta was clearly more organised at its peak than Iota currently is as a low-end Cat-5, Eta was almost certainly stronger than 140 knots.

I do think Iota could help Eta get upgraded, but not because of satellite estimates. The previous recon mission into Iota found Cat 5 winds in the NW quadrant, the one part that wasn’t sampled during Eta’s peak, and since the NW quad is expected to be the strongest for these kinds of westward moving systems, it’s reasonable Eta had >140 kt winds in that quad.

This is one of the very few seasons on record since 1851 in which “Groundhog Day” occurred more than twice, with representative storms bearing similar intensities tracking over the same areas on two, three, or more occasions. The amount of data ingested by both satellite and reconnaissance, to not mention NEXRAD, during this epic season will help the NHC compare and make very good posthumous estimates of the many landfalling hurricanes observed thus far. It is amazing to think that 2020 may well have featured two Cat-5s in November, and we have reliable data in our hands to verify the record.

Anyway, my estimates for the season: 30 NS / 12 H / 7 MH (Marco and Nana downgraded to TS, Gamma upgraded to H, and Zeta upgraded to MH).

[Shell Mound]

Gonzalo: 55 → 60 kt
TD Ten: 30 → 35 kt (upgrade to TS)
Josephine: 40 → 45 kt
Kyle: 45 → 55 kt
Marco: 65 → 60 kt
Nana: 65 → 55 kt
Paulette: 90 → 95 kt
Sally: 90 → 95 kt
Teddy: 120 → 115 kt
Gamma: 60 → 75 kt
Delta: 125 → 115 kt
Epsilon: 100 → 105 kt
Zeta: 95 → 100 kt
Eta: 130 → 150 kt

No other changes to the remaining systems

Update: added a few more changes

[tolakram]

Gonzalo: 55 → 60 kt
TD Ten: 30 → 35 kt (upgrade to TS)
Josephine: 40 → 45 kt
Kyle: 45 → 55 kt
Marco: 65 → 60 kt
Nana: 65 → 55 kt
Paulette: 90 → 95 kt
Sally: 90 → 95 kt
Teddy: 120 → 115 kt
Gamma: 60 → 75 kt
Delta: 125 → 115 kt
Epsilon: 100 → 105 kt
Zeta: 95 → 100 kt
Eta: 130 → 150 kt

No other changes to the remaining systems

Update: added a few more changes

Did you provide any reasoning for those up or downgrades?