What is this talk about "cooler waters" weakening

[logybogy]

...Ivan?

The gulf of mexico is boiling hot.

How do people figure the waters there are cool? I don't get it.

[btangy]

C Caribbean SSTs are slightly cooler, so there may some weakening in the near future.



This is reflected in the potential intensity maps. C Caribbean theoretically should support only Cat 3 intensity. It is entirely possible that decresing SSTs and a probable eyewall replacement cycle will weaken Ivan tomorrow. But, I'm really worried about Ivan once it reaches the NW Caribbean. GFS is showing a pretty good outflow jet due to an upper level low to the NE and no shear at all. Combine this with very warm SSTs in the NW Caribbean, and you got a scenario where a Cat 5 storm could thrive. [/list]

[ColinD]

This is reflected in the potential intensity maps. C Caribbean theoretically should support only Cat 3 intensity. It is entirely possible that decresing SSTs and a probable eyewall replacement cycle will weaken Ivan tomorrow. But, I'm really worried about Ivan once it reaches the NW Caribbean.

I said something similar earlier today. I think Ivan will be weaker at 5pm tomorrow than 5pm today for the same reasons you just gave. Agreed that the potential after it moves into the NW Caribbean is very high.

The waters in the path of Ivan for about the next 36 hours are not as warm as those in the NW Caribbean or East of South America.

BTW, I thinK Ivan is still in the region where a category 4 is the "max potential" but about to move into a region where it is category 3 until late Thursday.

[South Tampa]

I think that Ivan can drop to a three until it gets near Jamaicai and Southern Cuba then it goes back up to 4/5 depending on if it hits cuba or just cruises over the Isle of Youth.

[ColinD]

Tonight's discussion hit on it ...

The intensity forecast calls for Ivan to reach 135 kt in 12 hr on
the premise that the afternoon strengthening will continue. After
that...various analyses indicate that Ivan should pass over cooler
sea surface temperatures and reduced maximum potential intensity
for about 24 hr. This combined with an expected concentric eyewall
cycle should cause some weakening. Warmer water awaits over the
northwestern Caribbean and The Straits of Florida...which would
allow some strengthening when Ivan is not hitting land or
undergoing concentric eyewall cycles. After 96 hr...some westerly
shear may develop and the intensity forecast reflects a slight
weakening at 120 hr. While the intensity ups and Downs may be more
pronounced than forecast here...Ivan is expected to remain a major
hurricane through the forecast period.