Saturday, August 18, 2007

[Jyo_hurricane] Hurricane Dean: August 17, Update D

This is like the stock market week I believe - it's just going from bad to

Hurricane Dean is now a Category 4 storm and has slowed down to a forward
speed at a stately 18 mph (which is still a lot faster than other storms
I've seen). But he has slowed down over that lovely (!) warm ocean and in
a region of low wind shear.

The slowing down is in response to the high pressure being in his path as
I mentioned earlier. But he has also taken a more westward path, which is
also in response to that high pressure. He might even move a little
southward because that's the only way to get around the high without
slowing down too much (stalling is really really bad). If he maintains
this westward track overnight, then it looks like the high is strong
enough to keep him to the south, in which case landfall is more likely to
be in central America. If he resumes his west-northwestward track, then
the high is not as strong and it means that Jamaica, the Yucatan, and
somewhere on the Gulf (western/northern) will be affected. I think that at
this point the low that was over the Bahamas has stopped it's influence on
H. Dean, so the chance that it would go over DR/Haiti/Cuba is unlikely.

The minimum pressure is 937 mb and the maximum sustained winds are 145 mph
(126 kt). This makes him a mid-strength cat 4 (cat 4: 131-155mph; 114-135
kt). He is currently at about 15N, 66W. From an oceanic point of view, it
almost doesn't matter what his track his, once he has crossed 70W, he will
intensify further (if he doesn't before). At that point, although he will
be over approximately the same temperature waters, he will be over water
that is warm with depth. I'll go into that another day (maybe tomorrow),
but for now, it seems likely that he will reach cat 5 status by this time
tomorrow unless there is something in the atmosphere to hold him back.
This would be ahead of the official forecast, which doesn't have him as a
cat 5 until Monday. I hope the official intensity is the right one!

More tomorrow (did you think you'd get a day off?)
These remarks are just what I think/see regarding tropical storms - not
the opinion of any organization I represent. If you are making an
evacuation decision, please heed your local emergency management and the
National Hurricane Center's official forecast and the National Weather
Service announcements. This is not an official forecast. If I "run away,
run away" (Monty Python), I'll let you know.

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