Clark
(Meteorologist)
Sat Sep 11 2004 05:13 AM
Re: Thomas predicts landfall at Siesta Key

In looking at the records, I cannot recall a hurricane of any significance making landfall between Apalachicola and near Cedar Key since before the mid-1800s. That's not to say it can't happen -- you can take the approach that they are due, or take the approach that it's not likely to happen still.

NOGAPS is the furthest west with the storm, but something troubles me about the past few runs of the model. It develops a "child low" in the wake of Ivan in the central Caribbean -- essentially, a small piece of energy from Ivan remains behind as the storm moves away and sits over the central Caribbean Sea. I can't buy that happening, and I wonder if that has any impact on the track forecast. That is beyond my knowledge, unfortunately.

Ivan's jog to the west today was likely caused a bit by the asymmetry of the storm - convective drag. I can't go into more detail about it though as I don't full understand the mechanics behind it, however, but that appears to be one of the causes.

Intensity - don't know if I've ever seen a storm so round and robust as Ivan. I don't know how much longer it can keep it up, to tell the truth, as storms like this rarely stay this well defined for that long. Outflow is excellent SW counterclockwise to N and good in the remainder of the storm. It's just so well-defined as a storm. Recon should be out there shortly to give us a center fix -- will we break 920? My bets are on yes. The flight-level winds should begin/continue to respond to the drop in pressure beginning about now.

Track -- more concerned about parts of the peninsula today, particularly north of Tampa, but not willing to change my projections yet. Anyone from Pensacola to Key West needs to watch this one, as timing and wobbles may be critical in the long run. I still believe the area between Panama City and St. Marks is under the greatest threat, but due to slight weaknesses in the subtropical ridge and the position of the eastern trough, I'm not as confident in that as yesterday. The models I trust, though, are still within that narrower region...so we'll see how things play out.

Intensity -- the storm is more than likely a category 5 at this time, and depending upon eyewall replacement cycles will likely remain at such until it crosses Cuba. That could mean a day or two with a category 5 hurricane on our hands. I do not anticipate this storm remaining that strong after crossing Cuba nor restrengthening after doing so. Depending on the ultimate track, a low-end 3 to low-end 4 is what I am thinking at landfall. A track towards SW Florida or the central Panhandle is more likely at the higher end of that, whereas a track towards the western Florida peninsula is likely on the lower end of that. Shear is forecast to increase, but it has been forecast to increase for some time now yet has not done so. To tell the truth, I do not anticipate for it to do so to a large degree -- this storm is, in effect, controlling its own environment to some degree. And, once the storm rounds the base of the ridge and accelerates a bit towards landfall, the effective shear out of the S/SW may well be canceled out to some degree by the forward motion. Also of note is the position of the loop current in the Gulf and the recovery of the waters since Charley (as Frances stayed very near to shore and will likely have a minor impact on Ivan as it is)...to what degree they have recovered, particularly below the surface, and to what extent the loop current may be present in the eastern Gulf will control the intensity towards landfall.

Forward motion: the system should begin to slow a bit more once it passes Jamaica and take a day and a half to two days or so from now to inch towards Cuba. From there, the storm should slowly cross the island and gain some forward speed -- albeit not nearly as much as Charley -- as it passes northward towards Florida. Landfall in the four and a half to five day time period -- Wednesday -- is what I am looking at for right now. A track inland further south will likely bring the storm in sooner of course, perhaps as early as early Tuesday or even late Monday. Tending later, though.

And, as always...take everything you read besides the official forecast with a grain of salt. This represents my opinions only and, of course, I don't represent FSU or the FSU Superensemble in any way. By the way...the fee for getting access to the hurricane track forecasts was made known to me today...$30,000/year. Gulp.

In any case, let's see whatthis storm does in the next 36 hours -- hopefully by then, we'll know much more as to where it is going.

No comment about the "other" hurricanes!



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