The 5:00 PM advisory is out. Dean remains steady at 150 mph, according to the NHC. The discussion says, “THERE HAVE BEEN NO SIGNIFICANT CHANGES IN THE STRUCTURE OF DEAN DURING THE PAST SEVERAL HOURS.” The forecast, too, remains essentially unchanged, though the track’s “center line” has shifted ever so slightly to the left. Jamaica is still very much in the bull’s eye, however.
Alan Sullivan’s update on Dean is largely text-free. Instead, he’s offering three pictures worth 1,000 words each.
Meanwhile, Eric Berger is trying to give his readers “a sense of the near-historic intensification that Dean could undergo after crossing Jamaica.” He thinks Dean could rival the 2005 trifecta of Katrina, Rita and Wilma — the latter of which set the all-time record for lowest pressure recorded in the Atlantic basin.
P.S. Myself, I’m still worried about the intensification that Dean could undergo immediately before crossing Jamaica. I mentioned yesterday that the waters just east of the island are extremely warm, and “just as the Gulf Stream and the Loop Current tend to supercharge hurricanes that pass over them, I fear Dean could get a final, deadly burst of energy” from that bit of bathtub-like water. Alan Sullivan concurs. And the timing of the current eyewall replacement cycle makes things worse: as Margie Kieper commented earlier, “It appears [the cycle] will have time to complete before the hurricane reaches Jamaica.” Hurricanes generally weaken a bit during replacement cycles (though any weakening of Dean has yet to register in the NHC’s advisories), but they often strengthen once the cycle is over — and if the end of this cycle coincides with Dean’s arrival in the superheated water off Jamaica, the result could be disastrous. It would be sort of like throwing gasoline on a fire just as a gust of wind blows by. Boom!
The U.S. Gulf Coast has been spared the worst of several recent hurricanes, including Katrina, because of a combination of cooler water near shore and well-timed eyewall replacement cycles. With Dean and Jamaica, by contrast, the cycle timing is just awful, and the water near shore is anything but cool. I don’t want to be unduly alarmist or feed hysterical hype. But I fear the worst. As I said yesterday, “The only thing worse than a Category 5 hurricane making landfall is a strengthening Category 5 hurricane making landfall.” That’s precisely what I fear Dean will be for the people of that island.
In Sullivan’s words, “What can one say, except pray?”
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Categories: 2007 Hurricane Season
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August 18th, 2007 at 4:45:16 pm
Brendan - do you have any idea what the significance of the perceptible feature *within* the eye of Dean might be, in Alan Sullivan’s first picture ?
August 18th, 2007 at 5:03:16 pm
You mean the fact that there are some low-level clouds inside the eye? No special significance, except perhaps to indicate that an eyewall replacement cycle is underway and thus has made things a bit less “tightly wound” in there at the moment.
August 18th, 2007 at 5:41:05 pm
Brendan,
For us neophytes, could you explain how the eye wall replacement cycle works or send me to a good explanation somewhere else? I don’t believe I’ve ever heard that term before visiting your blog.
Thanks.
August 18th, 2007 at 5:52:05 pm
Never mind. I just found some info at NHC. Fascinating process. Scary, too.
Any word on the honeymooners you mentioned earlier? I hope they got out.
August 18th, 2007 at 5:59:20 pm
Brendan regards your GFDL vs. the world post I think 4-7 WAS dogging you,I’m learning as I go,I Don’t snark it’s just not productive.to close You helped me do a bit of searching meself so when I pass a judgement like I did it’s my own defense of you and your credibility.If iI should be banned by you,that’s O.K. I would understand,but I will defend you just the same,
Yours truly Bob
August 18th, 2007 at 6:16:36 pm
Bob, I appreciated your defense of me, and I certainly won’t ban you over it! (I’ve only banned one commenter in the whole history of my site, and that was for really egregious personal attacks on me and my family and friends.) I just felt pretty confident that you had misinterpreted 4-7’s comment, in part because 4-7 is a “regular” and does not make a habit of “dogging” me. But I certainly didn’t mean to attack or insult you for defending me! I was just trying to clarify the situation for all concerned.
Dogwood, I think my most thorough attempt at explaining eyewall replacement cycles was this post, back in 2004. Anyway I’m glad you found NOAA’s page on them. I don’t really understand them very well, I just know the results they can have.
August 18th, 2007 at 7:00:41 pm
Brendan, “dumb” question and you have probably answered it before: Hurricanes north of the equator spin counter clock wise, right? So is it correct to say that the worst place a person could be in the path of a hurricane, in the northern hemisphere, would be, say 10,20,30 miles, to the east of it?
August 18th, 2007 at 7:11:06 pm
Straycat, the worst place to be is the “right front quadrant.” If the storm is moving north into land, then yes, that would be anywhere from the center of the storm to 20 or 30 miles east of it (depending on the size of the eyewall). If the storm’s moving west, then it’s the north side. Basically, it’s whichever side the forward motion of the storm adds to, instead of subtracting from, the winds rotating around the center.
August 18th, 2007 at 7:16:48 pm
Have the Cayman Islands been mentioned? They seem to be in a direct path right after Jamaica.
August 18th, 2007 at 7:31:17 pm
I’m sure that someone will correct me if I’m wrong, but I believe that the absolute worst place to be is slightly to the right of the track because the forward motion of the storm increases the wind speed in that area. However, everywhere is dangerous. Note that the waters of Lake Ponchatrain in New Orleans were unleashed by a north wind on the left of the track of Katrina.
August 18th, 2007 at 10:59:36 pm
“… 4-7 is a ‘regular’ and does not make a habit of ‘dogging’ me.”
And he’d better Not, too, that’s My job around here. :) Woof. ;> Well. Unless Dogwood wood like to take it over. :] But then Straycat might stray into the territory. Hissss. :}