ATL: HARVEY - Models

[Alyono]

18Z GFS dissipates this in about 2 days

Maybe not.

fujiwara due to convective feedback

[Hurricaneman]

run is junk. Too much feedback going on there

The GFS isn't going to drop the convective feedback until a low has formed to latch onto

[Alyono]

run is junk. Too much feedback going on there

The GFS isn't going to drop the convective feedback until a low has formed to latch onto

won't matter. The feedback issue does not stop just because there is a defined low. It's a fundamental flaw in the model

[Hurricaneman]

The GFS says the thunderstorms that directly lead to a TS should be forming right about...................................now.

Convective feedback and it's making most of the GFS runs trash

[RL3AO]

Incredibly, it's ended up a little south of the 12z run after it's dance of (∂v/∂x - ∂u/∂y) maxima.

[RL3AO]

GFS has a borderline hurricane at 108 hrs. Since that almost certainly won't verify, the wave will be weaker and probably further south.

[otowntiger]

18Z GFS dissipates this in about 2 days

So More false alarms? Will this be another 99l? It's starting to sound like not much will come out of these waves? More sal, dry air and troughs to save the day?

[Alyono]

18Z GFS dissipates this in about 2 days

So More false alarms? Will this be another 99l? It's starting to sound like not much will come out of these waves? More sal, dry air and troughs to save the day?

I think something does form here, but not how the GFS says. It makes no dynamical sense

[RL3AO]

18Z GFS dissipates this in about 2 days

So More false alarms? Will this be another 99l? It's starting to sound like not much will come out of these waves? More sal, dry air and troughs to save the day?

I think the Euro has a good idea. In five days, an intensifying system east of the islands.

[FLpanhandle91]

Does the error of convective feedback also impact that accuracy in track as well? Or just intensity?

[RL3AO]

Does the error of convective feedback also impact that accuracy in track as well? Or just intensity?

Both. In the short term, the Fujiwhara interaction between the vorticity maxima put it north of where it will likely be. In the mid-term, by having a hurricane at day 5, it's moving the system NW towards the central Atlantic weakness. It's most likely to be a wave or weak tropical cyclone moving westward at day 5.

[FLpanhandle91]

Does the error of convective feedback also impact that accuracy in track as well? Or just intensity?

Both. In the short term, the Fujiwhara interaction between the vorticity maxima put it north of where it will likely be. In the mid-term, by having a hurricane at day 5, it's moving the system NW towards the central Atlantic weakness. It's most likely to be a wave or weak tropical cyclone moving westward at day 5.

Probably a noob question, but a stronger system would be influenced more by a steering influence like a weakness in a ridge than a weaker, less vertically prominent, system?

[RL3AO]

Probably a noob question, but a stronger system would be influenced more by a steering influence like a weakness in a ridge than a weaker, less vertically prominent, system?

In this case yes. Some make the mistake of assuming stronger = north which isn't always true, but in this case it is true.

Here's 700mb in 3 days. Strong easterlies with a ridge to the north of the system.



Here's 500mb in 3 days. A weakness to the NW of the system which the stronger modeled system is steered by more than a weak system would be.

[RL3AO]

120 hours out Euro vs GFS. I like the Euro solution more although maybe it's a bit too fast?

[FLpanhandle91]

Probably a noob question, but a stronger system would be influenced more by a steering influence like a weakness in a ridge than a weaker, less vertically prominent, system?

In this case yes. Some make the mistake of assuming stronger = north which isn't always true, but in this case it is true.

Here's 700mb in 3 days. Strong easterlies with a ridge to the north of the system.



Here's 500mb in 3 days. A weakness to the NW of the system which the stronger modeled system is steered by more than a weak system would be.

Thanks for the explanation!

So it would seem that a track quite a bit further south of the GFS model runs would make more sense. Seems like that would damn near put it into the eastern Caribbean next weekend.

[AutoPenalti]

I have a feeling that 91L is going to have the same issue as 99L did with its competing vorticies. Which may cause some faux runs with the GFS or the Euro.

[Kingarabian]

18z GFS hrs 120-240:

[Steve]

It takes a WSW dive into the Bahamas and moves north close to landfalling along the South Carolina Coast but paralleling and not going very far inland (eyewall 960s and close to/partially on land) It's too far out but it has moved a bit West from prior developing runs. Looks like it spins right along that curved part of the Coast from GA to NC).

[Kingarabian]

It takes a WSW dive into the Bahamas and moves north landfalling along the South Carolina Coast but paralleling and not going very far inland. It's too far out but it has moved a bit West from prior developing runs.

Joaquin 2015 esque?

[floridasun78]

look this could be soon invest looking better by hour it big tropical wave