Clark
(Meteorologist)
Thu Sep 09 2004 05:11 PM
Re: Ivan with Double Eyewalls? Weakens a bit

Ah, was just about to post on the other thread when I saw this one up.

In any case, Ivan continues to be a very well-developed hurricane, and save for interactions with Jamaica, should continue to maintain it's intensity -- or perhaps restrengthen a bit -- over the next day to two and a half days. The eyewall replacement cycle shouldn't be all that unexpected -- it's been awhile since the last one took place, and storms rarely do maintain this high of an intensity for such a long period of time. What would be unexpected would be for the outer eyewall to collapse and leave the inner eyewall, which is what happened with Charley...and would unfortunately lead to even more strengthening.

In the short term, a track over the length of Jamaica -- or perhaps just south of such -- is a likely bet. There's support for this from the models and the observations. I'd trend towards just south of the island with the building ridge to the storm's north, but it's still going to rake the island sometime tomorrow.

Longer-term, a path near the Isle of Youth followed by a track over the short end of Cuba is where I am leaning now. There's not really anything to force it to go further north or east than that. As an aside, the GFS seems to develop a peculiar weakness in the ridge currently to the north of the storm and propogate it westward, eroding the west side of the ridge and leading to the storm making an early turn northward. There are no indications this is taking place, yet alone will take place, so I feel that the Florida miss to the east can safely be put to rest. The spot near Cuba looks to be in about 3 days. NHC intensity of 140kt may be a little high, but not too far off.

Beyond there, I tend to favor a northwest-north-northwest-north track towards the Florida panhandle. This is consistant with my thinking from yesterday and is reflected in one of the threads from before...the particular one escapes me at the moment, however. The impending trough, I do not feel, will not completely pick up this storm. While the models are getting a better handle on the strength of the ridge now than they did with Frances, I think they are overdoing it with the extent and strength of the trough expected to turn Ivan. The observations, particularly to the south of the Mason/Dixon line, don't really support a sharp recurvature at this time.

It is of note that the storm should arrive to the coast in 4.5-6.5 days' time, depending on where it does make landfall. I believe 6 days is the most likely scenario for the Florida panhandle. It should also do so as a much weaker storm than it is now, albeit likely still a major hurricane. Think mid-3 to low-4 instead of 4/5. There is support in this track from the FSU Superensemble, which as noted in a previous NHC discussion follows this general track.

It's still too far out to pinpoint any set of locations, so everyone from NO east in the Gulf needs to watch this...but residents of the lower Keys and from between Biloxi and St. Marks need to watch this one closely. Pressed for a further narrowing of locations, I would look at Ft. Walton Beach to Apalachicola. In any event, this is going to be a storm that is going to affect a lot of people -- as it already has -- and I hope everyone's thoughts (and/or prayers) are with the residents of Jamaica for the coming day or two as this dangerous storm nears the island.



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