ATL: MILTON - Post-Tropical - Discussion

[USTropics]

A consistent thing I've noticed with rapidly/explosively intensifying hurricanes recently is SFMR readings are almost always higher than FL wind reduction estimates. This data characteristic has been seen in a lot of recent examples of RI hurricanes; Beryl and Lee come to mind as very recent examples. There are two likely explanations for this: the SFMR wind estimation algorithm is inaccurate at extremely high wind speeds, or winds mix down to the surface more efficiently in rapidly/explosively intensifying hurricanes and the standard FL wind reduction factor is misrepresentative. Either way, I expect that this will be an active area of research in the coming years.

It was similar research into how FL winds correlate to surface winds in 2004 that justified hurricane Andrew's post hoc Cat 5 upgrade a decade after it occurred. Perhaps analysis in the future might examine if standard FL wind reduction factors are universally applicable in RI/EI cases. Conversely, there may be research that corrects the algorithm that defines the relation between SFMR brightness temperature and surface windspeed for the high-end situations. Regardless, this may be an active area of research similar to the research advancements that were occurring in the early 2000s.

If any meteorologists have any insight into this that I am ignorant of, it would be greatly appreciated. This is just my inexpert opinion.

https://twitter.com/WxTca/status/1841103250105516208

SFMR data on NOAA hurricane hunters have been deemed unreliable and therefore not transmitted. Not sure if the same can be applied to AF hurricane hunters.

In any event, NHC has been increasingly sceptical of SFMR performance in higher wind speeds in recent years.

Yes, this is for all SFMR data, NOAA will not be using the data for operational purposes in 2024 due to calibration issues (basically they discovered the instruments were not properly calibrated initially). There is a research group and some students at FSU validating it now, take home being they said it's good up to about 80 m/s but can't be validated after that wind speed.

[Fancy1002]

On IR, it looks like it’s getting a bit ragged and winding down.

I just snapped that WV loop about 10 mins ago...looks fairly healthy to me currently

I’m referring to the almost symetrical Dome shape of the inner section becoming a bit ragged, not the eye area.

[Category5Kaiju]

A consistent thing I've noticed with rapidly/explosively intensifying hurricanes recently is SFMR readings are almost always higher than FL wind reduction estimates. This data characteristic has been seen in a lot of recent examples of RI hurricanes; Beryl and Lee come to mind as very recent examples. There are two likely explanations for this: the SFMR wind estimation algorithm is inaccurate at extremely high wind speeds, or winds mix down to the surface more efficiently in rapidly/explosively intensifying hurricanes and the standard FL wind reduction factor is misrepresentative. Either way, I expect that this will be an active area of research in the coming years.

It was similar research into how FL winds correlate to surface winds in 2004 that justified hurricane Andrew's post hoc Cat 5 upgrade a decade after it occurred. Perhaps analysis in the future might examine if standard FL wind reduction factors are universally applicable in RI/EI cases. Conversely, there may be research that corrects the algorithm that defines the relation between SFMR brightness temperature and surface windspeed for the high-end situations. Regardless, this may be an active area of research similar to the research advancements that were occurring in the early 2000s.

If any meteorologists have any insight into this that I am ignorant of, it would be greatly appreciated. This is just my inexpert opinion.

https://twitter.com/WxTca/status/1841103250105516208

SFMR data on NOAA hurricane hunters have been deemed unreliable and therefore not transmitted. Not sure if the same can be applied to AF hurricane hunters.

In any event, NHC has been increasingly sceptical of SFMR performance in higher wind speeds in recent years.

Yes, this is for all SFMR data, NOAA will not be using the data for operational purposes in 2024 due to calibration issues (basically they discovered the instruments were not properly calibrated initially). There is a research group and some students at FSU validating it now, take home being they said it's good up to about 80 m/s but can't be validated after that wind speed.

Wait, was SFMR data the reason why Iota was operationally a Category 5 at first? Back in 2020

[wx98]

May be seeing a slight reduction in intensity at the next update, in line with latest recon data and satellite trends. If this tracks south of Tampa Bay, there’ll be a radically different surge scenario, with the bay actually emptying (like with Ian). The bay side of St Petersburg and Clearwater could still have surge issues with offshore wind. Still well within the margin of error for track, but things are definitely trending south today. If trends hold, look for NHC to start to lower surge forecasts slightly for the bay and northward.

[FLLurker32]

I had to go back and look for my own sanity check.

NHC cone for Helene 24 hours prior to landfall did not even include the county where landfall ultimately occurred. The guidance models were in FAR better agreement then than they are now - and had been for a couple days - and were all wrong.

Milton has been even less predictable. Lest anyone get too comfortable of what they think they know..

this is factually not correct... the landfall point was a bit on the right side of the 24 hour cone, but it was within it... refer to https://www.nhc.noaa.gov/archive/2024/HELENE_graphics.php?product=5day_cone_no_line_and_wind

But... I will edit this post to emphasize that your basic point is correct, overly focusing on the track centerline is not wise as is living and dying with each model cycle and/or wobble (although wobble watching does become relevant shortly before landfall).

I understand that it landed in the far Eastern side of the final cone prior to landfall, that’s not what I’m referring to. If you start at advisory 11 on 9/25 and each subsequent advisory through the morning of 9/26 you will see that the ultimate landfall point went in and out of the most extreme eastern corner of the cone. Even more notable, the direction of entry changed drastically within those 24 hours, giving Eastern GA quite the surprise.

The point: We’ve come a long way in predicting hurricanes, but no one should be getting cocky because we still have a very long way to go. No one here within a warning or watch area should think they’re magically safe because “user12345” said so.

[ScottNAtlanta]

As plenty of people have mentioned weakening is relative. Yeah it’s better to get a 940’s system than a 920’s or lower. But don’t think for a that won’t be a historic storm for those who have to deal with it. Hurricane Betsy 1965 came in Grand Isle at 946. It was the benchmark storm in New Orleans for my parents generation (I was too young to remember) and was the big storm until Katrina hit. Milton could conceivably still hit in the 930’s which is worse. Gonna be tens of billions in damage across the state, and lives will be lost. Regardless of whether it goes in Tampa Bay or south, millions will still be affected. Sarasota-Bradenton has over 800k people and close to 900k if you consider down toward Venice. Orlando has over 2.5MM population and there is another 600k in Titusville/Melbourne/Mims/Cocoa Beach. Plus there’s a lot of people in between those statistical areas. This isn’t a big bend type storm or Panhandle hit because of the number of people that will be affected. It’s gonna be ugly maybe in ways we haven’t seen yet.

Just to expand on that...the biggest thing to fear in this storm will be water. The surge is not really something that fluctuates as winds fluctuate. It builds as it goes, and if the winds do die down before landfall that's not going to reduce the surge one bit. Katrina surprised a lot of people with how high the surge was even though it was weakening pretty quickly at landfall. Don't be lulled into thinking that a wind reduction will mean a less severe storm. The deadliest part of this storm (and most hurricanes) is water

[tolakram]

I think Milton has gotten a bit smaller.

The full Milton

[Ken711]

I think Milton has gotten a bit smaller.

The full Milton
https://i.imgur.com/q2LB7qM.gif

Small buzz saw.

[gailwarning]

The good news throughout this is that (even with the predicted expansion of wind radius) Milton is a small system. It could conceivably thread the needle between Sarasota and Fort Meyers, or maybe even Tampa and Sarasota. Of course all places would still receive hurricane force winds and potentially life threatening surge, but the damage corridor would be minimized.

A storm like Katrina at this heading would bring 20-30+ feet of surge over the entire region, and major hurricane impacts across the most populated corridor in Florida, and be a true catastrophe. Milton will be disastrous but more localized, like an Anti-Helene.

Will the EWRC that may be underway cause the size of the storm to increase?

[ScottNAtlanta]

I think Milton has gotten a bit smaller.

The full Milton
https://i.imgur.com/q2LB7qM.gif

Looks like it has contracted in.

[MississippiWx]

Creepy face returns.

[Steve]

As plenty of people have mentioned weakening is relative. Yeah it’s better to get a 940’s system than a 920’s or lower. But don’t think for a that won’t be a historic storm for those who have to deal with it. Hurricane Betsy 1965 came in Grand Isle at 946. It was the benchmark storm in New Orleans for my parents generation (I was too young to remember) and was the big storm until Katrina hit. Milton could conceivably still hit in the 930’s which is worse. Gonna be tens of billions in damage across the state, and lives will be lost. Regardless of whether it goes in Tampa Bay or south, millions will still be affected. Sarasota-Bradenton has over 800k people and close to 900k if you consider down toward Venice. Orlando has over 2.5MM population and there is another 600k in Titusville/Melbourne/Mims/Cocoa Beach. Plus there’s a lot of people in between those statistical areas. This isn’t a big bend type storm or Panhandle hit because of the number of people that will be affected. It’s gonna be ugly maybe in ways we haven’t seen yet.

Just to expand on that...the biggest thing to fear in this storm will be water. The surge is not really something that fluctuates as winds fluctuate. It builds as it goes, and if the winds do die down before landfall that's not going to reduce the surge one bit. Katrina surprised a lot of people with how high the surge was even though it was weakening pretty quickly at landfall. Don't be lulled into thinking that a wind reduction will mean a less severe storm. The deadliest part of this storm (and most hurricanes) is water

100. We were talking about it Saturday or Sunday. The dome of water (surge) is coming regardless of how much the pressure rises or the winds relax.

[Sciencerocks]

[USTropics]

https://twitter.com/WxTca/status/1841103250105516208

SFMR data on NOAA hurricane hunters have been deemed unreliable and therefore not transmitted. Not sure if the same can be applied to AF hurricane hunters.

In any event, NHC has been increasingly sceptical of SFMR performance in higher wind speeds in recent years.

Yes, this is for all SFMR data, NOAA will not be using the data for operational purposes in 2024 due to calibration issues (basically they discovered the instruments were not properly calibrated initially). There is a research group and some students at FSU validating it now, take home being they said it's good up to about 80 m/s but can't be validated after that wind speed.

Wait, was SFMR data the reason why Iota was operationally a Category 5 at first? Back in 2020

It absolutely was, and was the reason for the downgrade (it was assessed at operational flight level winds with the 90% rule for reduction to surface applied). It's particularly suspect when shoaling is involved (like near an island or landmass, as Iota was and Milton). From the reanalysis of Iota by Stacy Stewart: "ongoing research suggests there is a high bias of SFMR wind speeds in these high wind regimes.”

[ElectricStorm]

Eye drop supports 915mb

[Hurricane Mike]

I am surprised how small Milton still is, I wonder if that could maybe lessen the extent of the storm surge if it doesn't expand the wind field much in the next 24 hours.

[ScottNAtlanta]

Latest pass through the eye has it at 6nm and 916mb. No mention of concentric rings as of now

[Kazmit]

Creepy face returns.

[url]https://i.ibb.co/y5h7NYs/IMG-4363.jpg [/url]

Close enough, welcome back Hurricane Matthew.

[psyclone]

May be seeing a slight reduction in intensity at the next update, in line with latest recon data and satellite trends. If this tracks south of Tampa Bay, there’ll be a radically different surge scenario, with the bay actually emptying (like with Ian). The bay side of St Petersburg and Clearwater could still have surge issues with offshore wind. Still well within the margin of error for track, but things are definitely trending south today. If trends hold, look for NHC to start to lower surge forecasts slightly for the bay and northward.

Do you expect another southward adjustment at 11?

[Hypercane_Kyle]

https://i.imgur.com/wPMcSBs.gif

I've noticed Milton isn't really letting go of having a ton of lightning in its core. I wonder if the MSLP rise we are seeing is more-so due to expanding size as it interacts with the jet stream vs an EWRC. Visually it still looks impressive.