ATL GUSTAV: Tropical Depression - Discussion

[Wx_Warrior]

IMHO, we are within 24 hours of landfall so there wont be much major model shifting.

[CrazyC83]

98 kt flight-level winds found over 60 miles from the center...

[KWT]

Convection bursting over the eye again and thats blocking it out, I don't think its weakening but I suspect its not strengthening either, probably holding steady I guess.

Cat-3 into N.O is a pretty severe situation still and the track still suggests possibly a very bad situation for N.O, possibly as bad as Katrina given that Katrina was further east, even if Gustav does weaken a touch further N.O will still probably get higher winds than Katrina.

[Sabanic]

98 kt flight-level winds found over 60 miles from the center...

Still packing quite a punch, and will be bad at landfall where ever he goes.

Really cloudy and breezy here now too. Very muggy. No air at all.

[artist]

I wouldn't say the outflow is improving to the point of strengthening. There is definitely some fanning out of the clouds at SOME level to the south of the system, but you can clearly see the undercutting shear not letting the thunderstorm clouds (the blues and oranges on the color enhanced IR) fan that way.

Until I see the coldest cloud tops (blues and oranges) fan southward and not appear wall-like in structure on the southern side, I don't see any intensification. As a point, the eye on IR has filled in over the last hour or so with a convective burst over it, so I would expect the pressure to rise some more at this point.

Shear is expected to lessen somewhat per models over the next 6-12 hours (again "models"), but even if that happens I don't expect this to be more than a Category 2 or low end Category 3 at landfall based on the current quite ragged structure and lower oceanic heat content further north.

These are my personal observations and of course, do not reflect the opinion of Storm2k.

when Katrina came on shore she was a cat 3

[hiflyer]

As a fyi....there are no aircraft taking the New Orleans-Tampa line across the gulf....normally the preferred route for traffic from the west to the lower half of Florida....

New Orleans aiport is to close at 6pm CDT and will not be allowed as a evac location....couple flts still showing for 620 or so but that is it...carriers have been running larger than normal equip to get as many out as possible.

Couple notes...during Katrina I watched local New Orleans news streamed via the web and routinely some of the local weather guys appeared to be -removed- a different land fall which I fully believe was part of the problem with early evac. Air carriers were blamed for 'pulling the plug' too early but in this case the city is setting the time.

Gov Jindal from Louisiana is holding a presser stating latest he has been given from the NHC is Cat 3 now...with Trop storm winds by late night overnight at New Orleans.

[Sabanic]

I wouldn't say the outflow is improving to the point of strengthening. There is definitely some fanning out of the clouds at SOME level to the south of the system, but you can clearly see the undercutting shear not letting the thunderstorm clouds (the blues and oranges on the color enhanced IR) fan that way.

Until I see the coldest cloud tops (blues and oranges) fan southward and not appear wall-like in structure on the southern side, I don't see any intensification. As a point, the eye on IR has filled in over the last hour or so with a convective burst over it, so I would expect the pressure to rise some more at this point.

Shear is expected to lessen somewhat per models over the next 6-12 hours (again "models"), but even if that happens I don't expect this to be more than a Category 2 or low end Category 3 at landfall based on the current quite ragged structure and lower oceanic heat content further north.

These are my personal observations and of course, do not reflect the opinion of Storm2k.

when Katrina came on shore she was a cat 3

True but MGC got the brunt of the winds, and could again. At least almost as bad.

[jasons2k]

I wouldn't say the outflow is improving to the point of strengthening. There is definitely some fanning out of the clouds at SOME level to the south of the system, but you can clearly see the undercutting shear not letting the thunderstorm clouds (the blues and oranges on the color enhanced IR) fan that way.

Until I see the coldest cloud tops (blues and oranges) fan southward and not appear wall-like in structure on the southern side, I don't see any intensification. As a point, the eye on IR has filled in over the last hour or so with a convective burst over it, so I would expect the pressure to rise some more at this point.

Shear is expected to lessen somewhat per models over the next 6-12 hours (again "models"), but even if that happens I don't expect this to be more than a Category 2 or low end Category 3 at landfall.

These are my personal observations and of course, do not reflect the opinion of Storm2k.

I agree, if anything, it's weakening further. I don't see strengthening happening at all....

Please look at a visible loop instead. It is clearly reorganizing. I also know of some pro mets who have access to other views that show the center becoming better stacked than earlier. There is no question it is getting better organized and will probably commence a deepening phase soon. All I can say is if you don't believe me, have some patience, we will see soon enough.

[Derek Ortt]

check your geography, crazyc83

the recon is very near the eye

[soonertwister]

This may sound a little crazy, but I swear the latest geostationary visible image of Gustav seems to clearly show that a tiny new circulation center is forming well to the west and slightly south of the sad and broken eye to the ENE of it, right under the most intense convection.

http://www.nrlmry.navy.mil/tc_pages/tc0 ... Latest.htm

The image link could change image shots before you see it, I'm not sure where the image archive is.
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[Derek Ortt]

Please look at a visible loop instead. It is clearly reorganizing. I also know of some pro mets who have access to other views that show the center becoming better stacked than earlier. There is no question it is getting better organized and will probably commence a deepening phase soon. All I can say is if you don't believe me, have some patience, we will see soon enough.

I am not at all sure what you're seeing. I am seeing a cyclone that continues to experience strong shear.

I also see one with a very broad windfield, which is bad from a surge perspective

even if this comes in as a 2... remember the damage that Dolly caused and it was "just a borderline cat 1/2"

[RL3AO]

Recon shows the center right on forecast line.

[artist]

I foresee all the areas that were affected by Katrina will be again by Gustav, unless she misses her mark by alot. The surge, according to Derek, will be pretty much the same at cat 3 or 4.

[symplisusan]

We've got 25+ mph winds here in Largo, FL with higher gusts, but not much rain.

I hope and pray everyone stays safe that encounters this Monster!

[KWT]

Eye has been clouded over now by the strong convection still bursting on the SW side.

In some ways this is a good thing for the coast as the SW side seems to be stornger then the typical NE side in terms of the deep convection anyway but I think Gustav is still packing a monster punch.

As everyone knows, the track right now strongly suggest N.O danger.

[bigjohn]

[/quote]when Katrina came on shore she was a cat 3[/quote]

That seems to be a point of contention The NWS confirms that there were sustained winds of in excess of 142 mph in Slidell, LA. My SS scale says that is a Cat 4

[KWT]

I am not at all sure what you're seeing. I am seeing a cyclone that continues to experience strong shear.

I also see one with a very broad windfield, which is bad from a surge perspective

even if this comes in as a 2... remember the damage that Dolly caused and it was "just a borderline cat 1/2"

The other thing is obviously for any tall buildings you are going to see justs way higher then that, your still going to get winds probably cat-3 winds for example on the top of the taller buildings in N.O if this does just scrape past.

[WxGuy1]

Well, roughly 20 kts of shear persists near the center of Gustav per CIMSS analysis. It's awfully difficult to see any sort of rapid intensification in the face of such shear. That said, recent visible satellite imagery seems to show that Gustav continues to attempt to organize a better eye. It would certainly help Gustav to have the strong southwesterly upper-level winds (~30 kts) from south through east of the center ease up (or become northeasterly as should be the case for upper-level anticyclonic flow). Gustav should is in the warmest part of the loop current right now, so it may be in its best environment for appreciable strengthening it'll see in terms of oceanic heat. Personally, I don't think Gustav is weakening or strengthening much right now. I do like the look of wrapping Cb activity that occasionally flares up around the center (see the RAMSDIS Rapid Scan imagery HERE), but I don't think much of anything is going to happen unless/until the shear eases a bit. Yes, Gustav rapidly intensified yesterday in the face of moderate shear (10-20kts near the center), but it also had the warmest waters (as measured by TCHP) anywhere in the Atlantic under it. TCHP along the path of Gustav decreases steadily from here on out.

My best-guess intensity is mid-range Cat 3 at landfall. I don't really see much to portend significant weakening, though I also don't see much to think significant intensification (unless the shear really drops more than forecast). Certainly, the intensity will fluctuate in the next 24 hours.

Though Katrina was large and "only" officially Cat 3 at landfall (and it looked rather horrible on satellite compared to its previous times), it was also Cat 4-5 for a good amount of time, which allowed it to build up a massive surge. IMO, Gustav is unlikely to build up such a huge surge since it left its strong Cat 4 and Cat 5 surge on the south coast of Cuba (i.e. Cuba essentially blocked that built-up water from staying with the storm). This is not to trivialize the surge threat, however, since that part of the Gulf coastline is inherently prone to very high storm surges! In addition, the surge for NO may not be much less than Katrina if the storm wobbles a bit more right than forecast.

[superfly]

The other thing is obviously for any tall buildings you are going to see justs way higher then that, your still going to get winds probably cat-3 winds for example on the top of the taller buildings in N.O if this does just scrape past.

That's true for the coastal areas, but NOLA is well inland. Wind is not the problem, it's the surge into the lake.

[bigjohn]

Even if Gustav hits as a Cat 2, let's not forget that the NOLA damage was not causaed by the full force of Katrina which crossed the coast between approximately Biloxi and Slidell. NOLA probably only saw Cat 2 winds. But those winds and the accompanying surge were enough to devastate parts of The Big Easy. There are already reports that the Harvey Canal has weaknesses that are under repair that will leave it and the West Bank highly vulberable. The surge path into Lake Ponchartrain still leaves a lot of the Northshore vulnerable...many of whom are just nearing completion of their Katrina damage. So while after the thoughts yesterday of a Cat 4/5, the current strength may not excite you as a bystander. But if everything you had worked for in life was standing in the path of what Gustav apppears likely to be, you would have a sick feeling in your gut that would take you to your knees.