2020 TCRs

[aspen]

Sally up:
https://twitter.com/NHC_Atlantic/status/1382428225989656576

Wow, that’s a lot of TCRs today, and two of the most complicated and damaging Atlantic storms done. Only Laura, Teddy, Gamma, Zeta, Eta, and Iota left. I’m surprised it’s taken this long for Teddy to be finished.

[galaxy401]

I thought Isaias and Sally's intensities would have been upped slightly but not enough to raise a Category. Sally was quite tricky but 95 kts makes sense.

Also worth mentioning that the precursor to Sally was partially from Omar's remnants and the trough.

[ColdMiser123]

A little surprising that there really isn't any detailed analysis of the 140 mph borderline radial velocity bins at some radar scans in the TCR. That would have been really interesting to look into.

[ElectricStorm]

Yeah I figured it was a toss up for Cat 2 or 3 for Sally. I actually think Zeta has a better case for an upgrade to Cat 3. Gamma will likely be upgraded to Cat 1. Other than that I don't really see any other upgrades (still think Eta was a Cat 5 briefly but there's not any solid evidence to use for an upgrade)

[ColdMiser123]

Sally was 8 meters away from Cat 3 sustained winds at the standard 10 meter level, can't get much closer than that:

Sally produced sustained hurricane-force winds across portions of extreme southern
Alabama and the extreme western part of the Florida Panhandle near where it made landfall (Fig.
6). The strongest winds measured from a land or marine observation site were sustained winds
of 98 kt and a gust to 119 kt at the top of an 18-m meter mast at Ingram Bayou, Alabama.

[CrazyC83]

Sally was 8 meters away from Cat 3 sustained winds at the standard 10 meter level, can't get much closer than that:

Sally produced sustained hurricane-force winds across portions of extreme southern
Alabama and the extreme western part of the Florida Panhandle near where it made landfall (Fig.
6). The strongest winds measured from a land or marine observation site were sustained winds
of 98 kt and a gust to 119 kt at the top of an 18-m meter mast at Ingram Bayou, Alabama.

Sally was operationally 90 kt. I figured 95 kt was the best estimate, but that is sooooooo close. That wind would translate to about 95 kt at the standard elevation. On that basis alone, 100 kt may have been justifiable but inconclusive.

I disagree re: Cutler Bay landfall. I would have gone with 35 kt and tropical storm intensity there, based on the surface observation and the likelihood that stronger winds existed somewhere else.

[Hammy]

Sally up:
https://twitter.com/NHC_Atlantic/status/1382428225989656576

Wow, that’s a lot of TCRs today, and two of the most complicated and damaging Atlantic storms done. Only Laura, Teddy, Gamma, Zeta, Eta, and Iota left. I’m surprised it’s taken this long for Teddy to be finished.

I imagine there's quite a lot to analyze regarding the structure in the western Atlantic.

[ncforecaster89]

Given the 18 m elevation observation of a 98 kt MSW...I believe Sally was indeed a legitimate 100 kt Cat 3. As we all know, the highest MSW is never measured on land. Thus, the aforementioned wind reading is quite remarkable and strongly suggests the maximum sustained wind, located anywhere in the eyewall, was 100 kt. It correlates very well with the 110 kt 700 mb FLW measured by Recon, as well.

[CrazyC83]

Given the 18 m elevation observation of a 98 kt MSW...I believe Sally was indeed a legitimate 100 kt Cat 3. As we all know, the highest MSW is never measured on land. Thus, the aforementioned wind reading is quite remarkable and strongly suggests the maximum sustained wind, located anywhere in the eyewall, was 100 kt. It correlates very well with the 100 kt 700 mb FLW measured by Recon, as well.

That was measured over water so it would have good exposure (that reading alone supports 95 kt), but there is a point there. They did not mention radar velocities, which is surprising because that is usually the most reliable indicator near shore. The 88 kt SFMR should have little weight since any SFMR readings near shore are at best suspect and at worst completely unreliable (which is why Laura probably will not be upgraded to cat 5 despite an SFMR reading of 138 kt).

[aspen]

Given the 18 m elevation observation of a 98 kt MSW...I believe Sally was indeed a legitimate 100 kt Cat 3. As we all know, the highest MSW is never measured on land. Thus, the aforementioned wind reading is quite remarkable and strongly suggests the maximum sustained wind, located anywhere in the eyewall, was 100 kt. It correlates very well with the 100 kt 700 mb FLW measured by Recon, as well.

That was measured over water so it would have good exposure (that reading alone supports 95 kt), but there is a point there. They did not mention radar velocities, which is surprising because that is usually the most reliable indicator near shore. The 88 kt SFMR should have little weight since any SFMR readings near shore are at best suspect and at worst completely unreliable (which is why Laura probably will not be upgraded to cat 5 despite an SFMR reading of 138 kt).

It would be very shocking if Laura was upgraded to a Cat 5, even more so since Sally wasn’t upped to a 3. A slight upgrade to 135 kt is reasonable.

[ColdMiser123]

Given the 18 m elevation observation of a 98 kt MSW...I believe Sally was indeed a legitimate 100 kt Cat 3. As we all know, the highest MSW is never measured on land. Thus, the aforementioned wind reading is quite remarkable and strongly suggests the maximum sustained wind, located anywhere in the eyewall, was 100 kt. It correlates very well with the 100 kt 700 mb FLW measured by Recon, as well.

That was measured over water so it would have good exposure (that reading alone supports 95 kt), but there is a point there. They did not mention radar velocities, which is surprising because that is usually the most reliable indicator near shore. The 88 kt SFMR should have little weight since any SFMR readings near shore are at best suspect and at worst completely unreliable (which is why Laura probably will not be upgraded to cat 5 despite an SFMR reading of 138 kt).

It would be very shocking if Laura was upgraded to a Cat 5, even more so since Sally wasn’t upped to a 3. A slight upgrade to 135 kt is reasonable.

Peak FL wind was 148 kt which translates to 133 kt at the surface, this also lines up with the peak unflagged SFMR of 133 kt. There were flagged SFMR values that were higher. My estimate is that it was probably between 130-135 kt, just shy of a Cat 5.

[ColdMiser123]

Given the 18 m elevation observation of a 98 kt MSW...I believe Sally was indeed a legitimate 100 kt Cat 3. As we all know, the highest MSW is never measured on land. Thus, the aforementioned wind reading is quite remarkable and strongly suggests the maximum sustained wind, located anywhere in the eyewall, was 100 kt. It correlates very well with the 100 kt 700 mb FLW measured by Recon, as well.

The odds that observation captured the max wind is quite low, due to undersampling. Undersampling is also the reason the NHC says the SFMR values underestimated the max wind for Sally by up to 8%. This is useful to know going forward for Category 2/3 storms where there is a potential SFMR to FL wind mismatch.

[ClarCari]

I’m pleased to see Sally’s upgrade by 5kt since it does take into considerations the radar and dropsonde data. A full Category upgrade could have some data to back with this storm, but let’s be real, would also be something to satisfy us stat chasers who want to see 2005’s major hurricane record fall. Being so close to the next category can bring that out in all of us with these borderline storms. Being aware of that is important for the scientific part of us.

On another note, what was the largest upgrade made to a storm in post-analysis in wind speed and/or pressure?

[InfernoFlameCat]

I’m pleased to see Sally’s upgrade by 5kt since it does take into considerations the radar and dropsonde data. A full Category upgrade could have some data to back with this storm, but let’s be real, would also be something to satisfy us stat chasers who want to see 2005’s major hurricane record fall. Being so close to the next category can bring that out in all of us with these borderline storms. Being aware of that is important for the scientific part of us.

On another note, what was the largest upgrade made to a storm in post-analysis in wind speed and/or pressure?

Probably Patricia with an upgrade of 15mph at least in recent times

[ColdMiser123]

I’m pleased to see Sally’s upgrade by 5kt since it does take into considerations the radar and dropsonde data. A full Category upgrade could have some data to back with this storm, but let’s be real, would also be something to satisfy us stat chasers who want to see 2005’s major hurricane record fall. Being so close to the next category can bring that out in all of us with these borderline storms. Being aware of that is important for the scientific part of us.

On another note, what was the largest upgrade made to a storm in post-analysis in wind speed and/or pressure?

The TCR for Katrina lowered the landfall intensity considerably, from 125 kt operationally at 6 am CDT, down to 110 kt with the TCR when it made landfall at 6:10 am CDT.

The NHC used radar from on board aircraft to illustrate how Sally's structure was heavily tilted early on, but there isn't any mention of the radial velocity bins from WSR-88Ds when they assessed the landfall intensity for Sally. More specifically, no mention of the 121-122 kt velocities at ~1200 meters that showed up on multiple scans. Hopefully future studies look further into that.

[ncforecaster89]

I’m pleased to see Sally’s upgrade by 5kt since it does take into considerations the radar and dropsonde data. A full Category upgrade could have some data to back with this storm, but let’s be real, would also be something to satisfy us stat chasers who want to see 2005’s major hurricane record fall. Being so close to the next category can bring that out in all of us with these borderline storms. Being aware of that is important for the scientific part of us.

On another note, what was the largest upgrade made to a storm in post-analysis in wind speed and/or pressure?

The TCR for Katrina lowered the landfall intensity considerably, from 125 kt operationally at 6 am CDT, down to 110 kt with the TCR when it made landfall at 6:10 am CDT.

The NHC used radar from on board aircraft to illustrate how Sally's structure was heavily tilted early on, but there isn't any mention of the radial velocity bins from WSR-88Ds when they assessed the landfall intensity for Sally. More specifically, no mention of the 121-122 kt velocities at ~1200 meters that showed up on multiple scans. Hopefully future studies look further into that.

Completely forgot about those radial velocities which further correlates with a 100 kt Cat 3 intensity. As you so well articulated, it’s hard to conceptualize why the NHC didn’t take those into account.

Yet, they made reference to the assumed pressure gradients theorized by a storm chaser rather than real in-situ data. To clarify, the only legitimate way to determine the actual pressure gradient is to get two separate readings from different locations. Doing so from one barograph, at a singular location, is fraught with errors resulting from wobbles in track, short-term variances in translation speed, meso-vortices, etc. Consequently, I place no value to that particular data point and surprised the NHC included it in their report.

[NotoSans]

Gamma is out. Post season analysis finds it to be a hurricane.
https://www.nhc.noaa.gov/data/tcr/AL252020_Gamma.pdf

[MarioProtVI]

It seems like recon might’ve been under-sampling the storm before landfall, which combined with the satellite improvement and the pressure allowed it to become a hurricane. It was asynoptic actually too.

[Kazmit]

Anyone think Eta will be upgraded to a 5? Certainly a better case than Laura, and if it weren't for the recon issues, they might have found sufficient data.

[CrazyC83]

Given the deep pressure drop in the last few hours and surface data, I would have gone with 70-75 kt for Gamma. That was not available in real time though.