2020 TCRs

[MarioProtVI]

The downgrade triggers me somewhat because now the most active season has less ACE and zero C5s then the former record holder. If they’re going with this attitude now then Lorenzo and Matthew were in no way C5s.

[aspen]

The downgrade triggers me somewhat because now the most active season has less ACE and zero C5s then the former record holder. If they’re going with this attitude now then Lorenzo and Matthew were in no way C5s.

It sure is weird. 2020 pumped out 30 storms yet couldn’t hit 200 ACE nor produce a definitive Cat 5. Eta tried to be the ultra-intense late season Caribbean storm a la Wilma, but it’s just a typical high end Cat 4 wearing a T#8.0 mask.

I’m not sure about downgrading Lorenzo...it certainly was at least 130 kt.

[galaxy401]

Yeah that whole SMFR bias discussion is opening a can of worms regarding past Cat 5 storms including Matthew. Not sure I entirely agree with Iota's downgrade. The reason for the downgrade seems to be due to the SMFR winds must translate directly from FL winds which confuses me as well. I recall there many times where the peak SMFR winds were never fully consistent with FL winds and vice versa. Makes me more interested in the Laura and Eta reports though.

[EquusStorm]

[Iceresistance]

Noooooooo! How was that possible!?

[Hammy]

It appears shoaling was the nail in the coffin for retaining Cat 5. Nonetheless, for consistency sake both Eta and Iota are going into my records as Cat 5's.

[ncforecaster89]

This is a massive bruh moment. Like, it makes ZERO sense in the context of Matthew (upped to 145 kt entirely on SFMR) and Zeta (upped to 100 kt in the same season). Yet another addition to 2020’s multiple controversial post-season decisions, from not retiring storms like Isaias and Sally to keeping Sally as a Cat 2, although that makes more sense.

2020 really shouldn’t have given up after Iota if it wanted to continue the Cat 5 streak, and with Iota getting the boot, Matthew might too.

Matthew should be downgraded, like right now. There's no way it was stronger than Iota. Which means the Cat 5 streak in reality is likely 3 years, which while still impressive, it's much less so than a 5 year streak

https://i.imgur.com/8WU7074.png
If the NHC is now so conservative about SFMR in post-season analysis, could they potentially drop Laura and/or Eta to 125 kt? Could Michael also be at risk for a downgrade?

If anything, Michael should be increased to 145 kt based on a combination of all the data. The SFMR wasn’t the main reason they upgraded it, as radar data supported 145 kt. Recon measured 152 kt at 700 mb which equates to 137 kt at the surface, plus they determined Recon missed the peak winds and that alone supports 140 kt. Wind/pressure relationships, satellite estimates, radar velocity data, and FLWs all support at least 140 kt...and it’s certainly possible it may have been 145 kt as it crossed the coastline. Moreover, I strongly suspect the pressure was closer to 916 mb...as it was continuing to rapidly intensify through landfall.

[Sciencerocks]

It appears shoaling was the nail in the coffin for retaining Cat 5. Nonetheless, for consistency sake both Eta and Iota are going into my records as Cat 5's.

There's no question in my mind. Eta was probably 145-150 knots! I'd lean on satellite estimates being that recon hardly had a chance to get any solid data.

[Iceresistance]

It appears shoaling was the nail in the coffin for retaining Cat 5. Nonetheless, for consistency sake both Eta and Iota are going into my records as Cat 5's.

There's no question in my mind. Eta was probably 145-150 knots! I'd lean on satellite estimates being that recon hardly had a chance to get any solid data.

It seems like that Eta is our only hope as a CAT 5 for 2020 . . .

[CyclonicFury]

It appears shoaling was the nail in the coffin for retaining Cat 5. Nonetheless, for consistency sake both Eta and Iota are going into my records as Cat 5's.

There's no question in my mind. Eta was probably 145-150 knots! I'd lean on satellite estimates being that recon hardly had a chance to get any solid data.

It seems like that Eta is our only hope as a CAT 5 for 2020 . . .

Very unlikely Eta gets upgraded to 140 knots. The recon data we do have does not support Category 5 status at all. The maximum flight level wind was 137 knots, with the maximum SFMR of 135 knots. I think a slight upgrade to 135 knots is possible considering the document released by NHC a few weeks back had Eta at 135 knots.

[ncforecaster89]

I agree, as others have already stated, that Matthew and Lorenzo should both be downgraded based on the apparent high bias of the SFMR data in surface winds > 120 kt. Might be an unpopular opinion, but I’ve always felt Dorian was overestimated with the 160 kt estimate; which is way too high a figure considering the 700 mb FLWs of 161 kt (corresponds to only 145 kt). The SFMR is the only data that supported such an extreme estimate and I feel 150 kt is likely a more accurate representation of its MSW at its peak.

Although Dorian currently sits above Irma, the exclusion of the SFMR data would likely put them at the same intensity of 150 kt. Personally, I find Irma to be the more impressive hurricane of the two and actually had a higher 700 mb FLW of 164 kt. Even though I still think of Dorian as an incredibly powerful Cat 5, it should not be tied with the GLDH of 1935...based on the available data.

[aspen]

There's no question in my mind. Eta was probably 145-150 knots! I'd lean on satellite estimates being that recon hardly had a chance to get any solid data.

It seems like that Eta is our only hope as a CAT 5 for 2020 . . .

Very unlikely Eta gets upgraded to 140 knots. The recon data we do have does not support Category 5 status at all. The maximum flight level wind was 137 knots, with the maximum SFMR of 135 knots. I think a slight upgrade to 135 knots is possible considering the document released by NHC a few weeks back had Eta at 135 knots.

If only recon went in for a third pass...

135 kt for the final recon pass that night is very reasonable. However, given the rate Eta’s pressure was falling and the fact that it was a good few hours before the developing EWRC really started to have an impact, it can be argued that Eta bottomed out several mbar lower than the current 923 mbar. Maybe it was comparable to Iota in pressure. Also, recon found a minimum extrapolated pressure of 913 mbar in Iota; how was that converted to 917 mbar?

[ElectricStorm]

I just feel like with Iota's downgrade, they're going to have to go back and reanalyze a bunch of other storms. Matthew is the most obvious one but they're gonna have to look at pretty much every intense storm again. It also bring up the question of why did they downgrade Iota but not storms like Nana, which didn't have much evidence at all that it was even a hurricane...Idk I just kinda feel like it would have been better if they left Iota at 140kts until they got more definitive data on the SFMR. But that's just my take, again I'm not the experts.

It also shows that we're probably not gonna see a whole lot of Cat 5s going forward as now they're really gonna wait for those 150kt+ SFMR values. We probably won't see them go above 150kts for a long time unless we end up with like a Wilma type storm.

[SouthDadeFish]

A lot of strong feelings about a 5 kt change that is well within the margin of uncertainty of our estimates of max wind in TCs!

The state of the science is constantly evolving. Unfortunately, it's difficult to validate these SFMR readings in intense TCs as we don't have a lot of dropsondes in such wind conditions.

For those that don't know, the SFMR readings are just an estimate of the surface wind speed based on microwave brightness temperature observations of blowing sea foam. The surface winds are estimated based on a given algorithm that try to match the microwave brightness temperatures to dropsonde observations. So at these high wind speeds, it's hard to know what the "truth" is. Over the last few years, we have sampled more intense hurricanes and have more data points to fit the SFMR algorithm, comparing to dropsonde observations. The new observations suggest the previous algorithm may have overestimated surface winds in these intense TCs, but again, there is still quite a bit of uncertainty here.

If you're interested in more, here's one paper you can check out: https://journals.ametsoc.org/view/journ ... 0028_1.xml

The NHC is just going with their best estimate based of the data and knowledge available to them at the time. As of now, it seems most responsible to change Iota's max winds to 135 kt. Pending an ongoing SFMR study, this analysis may be changed either up or down. The same can be said for other recent TCs. There is a lot of time and effort put into these analyses. They aren't perfect, but they're the best we have right now.

[Hypercane_Kyle]

Add Emily (2005) to the list of Category 5 hurricanes that should be downgraded IMHO. Matthew is the other obvious one, as mentioned.

[NotoSans]

Add Emily (2005) to the list of Category 5 hurricanes that should be downgraded IMHO. Matthew is the other obvious one, as mentioned.

Emily’s assessment is based solely on flight-level data. In fact, Emily’s fight-level winds are 1kt higher than Michael at 153kt. And the SFMR algorithm is changed in 2015 which contributes to the alleged high bias. There’s absolutely no problem with assigning Emily as a category 5.

[Shell Mound]

 https://twitter.com/AndyHazelton/status/1394769639138283526

[InfernoFlameCat]

Please tell me this is a nightmare and that Iota was not actually downgraded. 917mb bro. 917. Matthew should be cat 3 at this point.

[InfernoFlameCat]

On a side note, the only thing tha would ever make up for such a decision is if the Atlantic says Bs and makes a OTS 190 knot Hurricane. Just saying.

[InfernoFlameCat]

Also if we have 3 failed cat 5s, that would be a first.