ATL: ISAAC - Post-Tropical - Discussion

[LowndesCoFire]

Watches / Warnings now in effect for Big Bend / Panhandle Coast. Showing on local NWS but not on NHC site. Is that usually the call of the NHC or local offices?

Those watches look like they are offshore, not on the coast.

Ahh correct...marine areas only. They issued a hurricane local statement for inland areas. No watches/warnings inland yet. Good eye!

[cheezyWXguy]

No one has answered my question about what is going to happen IF Isaac eats up the trough that is in front of him.

There is no trough in front of Isaac atm. Isaac is part of a broad area of low pressure and theres another vort max over near western Cuba. Read the 5pm discussion from the NHC, they mention this and explain the evolution of the situation quite well.

[SouthDadeFish]

Yeah, I just watched the 1km loop and I see some convection starting to build very near the center. Not decoupled. My mistake. Still has some work to do, but I suppose there is a lot of potential here shortly if it can wrap in all that moisture to its NW.

[Blinhart]

No one has answered my question about what is going to happen IF Isaac eats up the trough that is in front of him.

There is no trough in front of Isaac atm. Isaac is part of a broad area of low pressure and theres another vort max over near western Cuba. Read the 5pm discussion from the NHC, they mention this and explain the evolution of the situation quite well.

I must be missing part of the discussion, because I don't see that.

[LowndesCoFire]

No one has answered my question about what is going to happen IF Isaac eats up the trough that is in front of him.

Eats it up? Tropical cyclones don't "eat" troughs. Troughs have the ability to absorb tropical cyclones and transition them into extratropical ones, but that's about it other than when dealing with steering.

That's strange because the TWC stated that what is in front of Isaac should soon be entrained into Isaac, so what do they mean by that???

My guess is that it is the same thing that happens when dry air comes near a cyclone, you will see it wrap around the cyclone's convection. Guess they are thinking that Isaac will simply absorb the energy as he gets closer to it.

[wjs3]

Interesting. Just heard on the The Weather Channel that a second low developed under Cuba and to the South and West of the primary one that is going to tug it more West. May be why models shifted a little more West. Watching very closely here though.

What you may have heard is that there is an UPPER-LEVEL low south of Cuba that should direct Isaac NW then WNW as forecast.

I think this is related to the surface low/vort max here:

http://www.nhc.noaa.gov/tafb_latest/CAR_latest.gif

And mentioned in the discussion as what sounds like a fuji...

ISAAC IS CURRENTLY PART OF A
LARGE LOW/MID-LEVEL LOW PRESSURE SYSTEM COVERING THE NORTHWESTERN
CARIBBEAN SEA AND THE ADJACENT LAND AND OCEAN AREAS. THIS LOW
PRESSURE AREA HAS A SECOND VORTICITY CENTER BETWEEN JAMAICA AND THE
CAYMAN ISLANDS...AND FOR THE NEXT 24-36 HR ISAAC AND THIS CENTER
WILL LIKELY ROTATE AROUND EACH OTHER. BASED ON THIS EXPECTATION...
THE FORECAST TRACK SHOWS ISAAC MOVING NORTHWESTWARD FOR 12 HR OR
SO...FOLLOWED BY A TURN TOWARD THE WEST-NORTHWEST. IT IS POSSIBLE
THE STORM COULD MAKE A SHARPER TURN THAN FORECAST...AS THE UKMET IS
SHOWING AN ALMOST DUE WEST MOTION BETWEEN THE FLORIDA KEYS AND CUBA
NEAR THE 36 HR POINT.

[cheezyWXguy]

Yeah, I just watched the 1km loop and I see some convection starting to build very near the center. Not decoupled. My mistake. Still has some work to do, but I suppose there is a lot of potential here shortly if it can wrap in all that moisture to its NW.

Yeah, its really got a ways to go, but the center is clearly offshore now and low level structure has been improving most of the day despite the lack of any real convective structure. Once d-min passes, I think we should see this thing start strengthening tonight.

[Aric Dunn]

slowly moving away from the coast. circ is starting to become better defined as well. could strengthen over night quite a bit if it gets a little farther away.

[TropicalAnalystwx13]

No one has answered my question about what is going to happen IF Isaac eats up the trough that is in front of him.

Eats it up? Tropical cyclones don't "eat" troughs. Troughs have the ability to absorb tropical cyclones and transition them into extratropical ones, but that's about it other than when dealing with steering.

That's strange because the TWC stated that what is in front of Isaac should soon be entrained into Isaac, so what do they mean by that???

You must be referring to the low/mid-level low across the northwestern Caribbean, not a trough. This low is expected to drag Isaac more towards the west-northwest as it approaches the Florida Keys tomorrow. After that, Isaac should either get far enough away from the low for it to influence it, or it may just absorb the low...nothing changes either way. Absorption would have no effect on the storm, except for increased energy and convection.

[SFLcane]

Interesting. Just heard on the The Weather Channel that a second low developed under Cuba and to the South and West of the primary one that is going to tug it more West. May be why models shifted a little more West. Watching very closely here though.

What you may have heard is that there is an UPPER-LEVEL low south of Cuba that should direct Isaac NW then WNW as forecast.

Wxman57 wont that then bring stronger winds into metro areas of dade and broward?

[Blinhart]

Interesting. Just heard on the The Weather Channel that a second low developed under Cuba and to the South and West of the primary one that is going to tug it more West. May be why models shifted a little more West. Watching very closely here though.

What you may have heard is that there is an UPPER-LEVEL low south of Cuba that should direct Isaac NW then WNW as forecast.

I think this is related to the surface low/vort max here:

http://www.nhc.noaa.gov/tafb_latest/CAR_latest.gif

And mentioned in the discussion as what sounds like a fuji...

ISAAC IS CURRENTLY PART OF A
LARGE LOW/MID-LEVEL LOW PRESSURE SYSTEM COVERING THE NORTHWESTERN
CARIBBEAN SEA AND THE ADJACENT LAND AND OCEAN AREAS. THIS LOW
PRESSURE AREA HAS A SECOND VORTICITY CENTER BETWEEN JAMAICA AND THE
CAYMAN ISLANDS...AND FOR THE NEXT 24-36 HR ISAAC AND THIS CENTER
WILL LIKELY ROTATE AROUND EACH OTHER. BASED ON THIS EXPECTATION...
THE FORECAST TRACK SHOWS ISAAC MOVING NORTHWESTWARD FOR 12 HR OR
SO...FOLLOWED BY A TURN TOWARD THE WEST-NORTHWEST. IT IS POSSIBLE
THE STORM COULD MAKE A SHARPER TURN THAN FORECAST...AS THE UKMET IS
SHOWING AN ALMOST DUE WEST MOTION BETWEEN THE FLORIDA KEYS AND CUBA
NEAR THE 36 HR POINT.

That is scary. i really hope that doesn't come to fruition as that can change the models drastically and cause the system to have more time over the GoM.

[Time_Zone]

This is a bit of a dumb question but....which place(s) would be the most suseceptible and vulnerable to a hurricane currently? Regarding Isaac's projected track.

Basically where is the "worst case scenario" thats within reason for Isaac to eventually end up making landfall once in the GOM.

Anybody?

[tgenius]

If it were to somehow bomb out would that make it go poleward more as other storms have?

[Blinhart]

This is a bit of a dumb question but....which place(s) would be the most suseceptible and vulnerable to a hurricane currently? Regarding Isaac's projected track.

Basically where is the "worst case scenario" thats within reason for Isaac to eventually end up making landfall once in the GOM.

Anybody?

My personal opinion is that anywheres between Galveston, Tx, and Tallahassee, Fl. I know that is a broad area, but right now I see the splits in the models, and the new discussion about possibly going further West at the beginning, anywheres on the Northern part of the GoM is open to it making landfall.

[Aric Dunn]

I can see west moving cu clouds offshore so its pulling away only a matter of time. environment is good for intensification.

['CaneFreak]

Well, you would have two competing effects if it were to "somehow" bomb out...

1) The tendency for cyclones to curve right based on the coriolis force balance

2) A significant amount of latent heating generated ahead of the storm would tend to add significant heating to the ridge, thereby strengthening it, and in the process sending the storm further west...

If it were to somehow bomb out would that make it go poleward more as other storms have?

[TropicalAnalystwx13]

The 18z GFS shifted even farther west. Interested to see other runs of the other models tonight.

Taking the western side of the cone would be the worst case scenario for this time. More time over water and higher Heat Content.

[Aric Dunn]

convection really building on the ne, n and nw quads this evening. it may be getting pulled to the convection. last few frames show it pulling away a little faster not sure yet for sure.

[Recurve]

Latest rainbow IR shows clear air at what I assume is the low center and a flareup at the NW that appears to be wrapping around it. If that's not an illusion, it's showing off the coast and looking to suck on some Gulf Stream.



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[Time_Zone]

This is a bit of a dumb question but....which place(s) would be the most suseceptible and vulnerable to a hurricane currently? Regarding Isaac's projected track.

Basically where is the "worst case scenario" thats within reason for Isaac to eventually end up making landfall once in the GOM.

Anybody?

My personal opinion is that anywheres between Galveston, Tx, and Tallahassee, Fl. I know that is a broad area, but right now I see the splits in the models, and the new discussion about possibly going further West at the beginning, anywheres on the Northern part of the GoM is open to it making landfall.

I know that, thanks for responding either way. But I mean, where would be the "WORST" place for Isaac to end up? as in the place which could possibly take the worst hit.