ATL: LAURA - Post-Tropical - Discussion

[Ubuntwo]

Watching Ken Graham on TWC, hasn't even realized Laura made landfall keeps talking how it is south of the Base.

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

Interestingly enough this NW jog almost puts Laura right back on the 12z TVCN track

[NDG]

Watching Ken Graham on TWC, hasn't even realized Laura made landfall keeps talking how it is south of the Base.

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

Can you link that radar?

https://www.metoc.navy.mil/fwcn/fwcn.html#!/swr.html

[Ubuntwo]

Watching Ken Graham on TWC, hasn't even realized Laura made landfall keeps talking how it is south of the Base.

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

That's the mid level circulation.

Considering surface observations and the beam height there, it's not.

[Hypercane_Kyle]

Amateur opinion alert, but I'm not convinced what we're seeing on radar is the LLC. NHC mentioned there were mesocyclones found by the recon. Could be a mesocyclone embedded within a much broader LLC.

[ozonepete]

In my opinion Laura has taken a hit from Hispaniola and is about to take another worse one from Cuba...

Cuba's mountains are much less of an obstacle than the DR and Haiti. Cuba has fairly high mountains only in the southeast portion; Laura will be past them in a few hours. The rest gets quite flat except for a small portion in central Cuba.
It is also so narrow from north to south that moisture is not blocked off as much at all.

https://i.imgur.com/8CGfjND.png

Why was Ike so severely affected after moving over Cuba--was it simply the amount of time it took to cross it?

These are such different situations and I haven't looked at it extensively but here's some things:
1. Ike was a powerful hurricane when it started crossing Cuba. The strongest storms take the worst degeneration from mountain ranges.
2. Ike spent 2 days over or very close to Cuba.
3. Ike was starting to greatly enlarge its windfield/size as it was crossing Cuba. This was a big factor in its loss of power.
4. Ike was starting an eyewall replacement cycle as it was exiting western Cuba. Another factor that can cause weakening before the new eye has fully formed.

Laura will spend a little over a day over Cuba. It entered and will leave as a TS so suffer much less degradation; there's much less vertical structure to disrupt.
It is not substantially increasing its windfield so far and obviously no ERCs.

[LarryWx]

Hey Larry, always good to hear from you. I agree with your landfall pressure estimates. But I think the system could be stronger since Marco is moving fast, so the time it has to upwell could be reduced. Laura will also be moving at a steady clip meaning it could spend less time over upwelled waters. We shall see. So far it's not looking good.

Love me some Larry. King, do you like that 955-975 range on a Texas landfall? Seems like 940’s could easily be in play.

I think any Texas solution favors something near a 930mb landfall due to more time over warm waters.

If Marco weren't there and Laura were more isolated, I'd say this would be possible. But near perfect conditions are needed for that and with Marco there, conditions aren't nearly perfect imo. So, I think cat 2 or 3 landfall most likely even into TX and will stick with 955-975 for landfall now, which is bad enough as it is. If it gets to the 940s or 930s at LF, I'll clearly be wrong.

[Jr0d]

Amateur opinion alert, but I'm not convinced what we're seeing on radar is the LLC. NHC mentioned there were mesocyclones found by the recon. Could be a mesocyclone embedded within a much broader LLC.

Its pretty clear on the GTMO radar that that is the LLC at least with my amateur eyes. Wind out of the West at GTMO also indicates that in more than a me so vortex.

[wx98]

Amateur opinion alert, but I'm not convinced what we're seeing on radar is the LLC. NHC mentioned there were mesocyclones found by the recon. Could be a mesocyclone embedded within a much broader LLC.

It sure looks like the LLC is inland on radar to me but if your analysis is correct, the LLC is just right along the coast.

[cycloneye]

Watching Ken Graham on TWC, hasn't even realized Laura made landfall keeps talking how it is south of the Base.

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

Do you have the link?

[cycloneye]

 https://twitter.com/AndyHazelton/status/1297660552961982464

[cheezyWXguy]

Amateur opinion alert, but I'm not convinced what we're seeing on radar is the LLC. NHC mentioned there were mesocyclones found by the recon. Could be a mesocyclone embedded within a much broader LLC.

It sure looks like the LLC is inland on radar to me but if your analysis is correct, the LLC is just right along the coast.

Looks to be skirting the coast just inland, just north of due west. Could be rough for laura in the short term, as this is where the tallest mountains are, but in the long run this motion would likely keep it over water for longer

[wx98]

Amateur opinion alert, but I'm not convinced what we're seeing on radar is the LLC. NHC mentioned there were mesocyclones found by the recon. Could be a mesocyclone embedded within a much broader LLC.

It sure looks like the LLC is inland on radar to me but if your analysis is correct, the LLC is just right along the coast.

Looks to be skirting the coast just inland, just north of due west. Could be rough for laura in the short term, as this is where the tallest mountains are, but in the long run this motion would likely keep it over water for longer

There is a narrow valley it may can get through WNW of Guantanamo that would save the center from the tallest mountains. But inflow will probably take a hit.

[NDG]

Watching Ken Graham on TWC, hasn't even realized Laura made landfall keeps talking how it is south of the Base.

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

That's the mid level circulation.

Is not the mid level circulation, surface reports from the Naval Base support the radar image of the LLC.

[NDG]

Watching Ken Graham on TWC, hasn't even realized Laura made landfall keeps talking how it is south of the Base.

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

Do you have the link?

https://www.metoc.navy.mil/fwcn/fwcn.html#!/swr.html

[HurricaneEdouard]

I’m guessing it’s because Ike, being a system with a developed core, was far more fragile to land interaction compared to weak/broad systems like Isaias and Laura.

Indeed. We saw this with Georges and Gustav as well, and many others. A major hurricane that tracks across Cuba or Hispaniola or both tends to have a difficult time getting reorganised in the Gulf; in fact, they nearly always underperform their intensity forecasts, and while the models predict they will restrengthen into major hurricanes, they tend to just broaden their windfield and make landfall as sprawling Category 2 hurricanes (often with a major hurricane's surge). If they move slowly, they sometimes have the time to restrengthen (which is what very nearly happened with Ike at the last second), but if they move too slowly, they run into the fact that the Gulf is easily upwelled outside of the Loop Current - so betting on a weaker storm than what the models predict, when it's a major hurricane encountering the Greater Antilles, is usually a safe bet.

(Same applies to outside the Gulf too, for that matter. David from 1979 comes to mind.)

I would like to read a study comparing different storm intensities and how they fared after interaction with the Antilles. Would be interesting to compare developing cyclones with stronger ones.

I actually plan on writing an amateur's study myself, using NHC forecast advisories and past model data, and every storm crossing the Greater Antilles to 1979 or so.

[msbee]

https://twitter.com/AndyHazelton/status/1297660552961982464

glad to see your post, Luis. I was wondering how things were in PR.

[Nimbus]

Amateur opinion alert, but I'm not convinced what we're seeing on radar is the LLC. NHC mentioned there were mesocyclones found by the recon. Could be a mesocyclone embedded within a much broader LLC.

It sure looks like the LLC is inland on radar to me but if your analysis is correct, the LLC is just right along the coast.

Looks to be skirting the coast just inland, just north of due west. Could be rough for laura in the short term, as this is where the tallest mountains are, but in the long run this motion would likely keep it over water for longer

The mountains are causing the convection offshore again tonight but the center will be back out over water soon.

[wx98]

Indeed. We saw this with Georges and Gustav as well, and many others. A major hurricane that tracks across Cuba or Hispaniola or both tends to have a difficult time getting reorganised in the Gulf; in fact, they nearly always underperform their intensity forecasts, and while the models predict they will restrengthen into major hurricanes, they tend to just broaden their windfield and make landfall as sprawling Category 2 hurricanes (often with a major hurricane's surge). If they move slowly, they sometimes have the time to restrengthen (which is what very nearly happened with Ike at the last second), but if they move too slowly, they run into the fact that the Gulf is easily upwelled outside of the Loop Current - so betting on a weaker storm than what the models predict, when it's a major hurricane encountering the Greater Antilles, is usually a safe bet.

(Same applies to outside the Gulf too, for that matter. David from 1979 comes to mind.)

I would like to read a study comparing different storm intensities and how they fared after interaction with the Antilles. Would be interesting to compare developing cyclones with stronger ones.

I actually plan on writing an amateur's study myself, using NHC forecast advisories and past model data, and every storm crossing the Greater Antilles to 1979 or so.

This is a very good idea. Forecasting can be majorly improved if smaller-scale features (such as here with storm-land interaction) can be accurately studied and understood. Why does this storm weaken and that one strengthen? Why does this one bounce around and tighten up and why does that one plow straight in and fall apart? Or why does Laura plow straight in and come out better?

[Nuno]

Indeed. We saw this with Georges and Gustav as well, and many others. A major hurricane that tracks across Cuba or Hispaniola or both tends to have a difficult time getting reorganised in the Gulf; in fact, they nearly always underperform their intensity forecasts, and while the models predict they will restrengthen into major hurricanes, they tend to just broaden their windfield and make landfall as sprawling Category 2 hurricanes (often with a major hurricane's surge). If they move slowly, they sometimes have the time to restrengthen (which is what very nearly happened with Ike at the last second), but if they move too slowly, they run into the fact that the Gulf is easily upwelled outside of the Loop Current - so betting on a weaker storm than what the models predict, when it's a major hurricane encountering the Greater Antilles, is usually a safe bet.

(Same applies to outside the Gulf too, for that matter. David from 1979 comes to mind.)

I would like to read a study comparing different storm intensities and how they fared after interaction with the Antilles. Would be interesting to compare developing cyclones with stronger ones.

I actually plan on writing an amateur's study myself, using NHC forecast advisories and past model data, and every storm crossing the Greater Antilles to 1979 or so.

Please keep me informed, I'd love to check it out

[abk_0710]

I am assuming New Orleans can't yet let their guard down?