22 August 2007

Dean makes second Mexico landfall...

At about 17Z today, Hurricane Dean made landfall (again) between Tampico and Veracruz.  Dean exited Yucatan as a 70kt storm, barely holding onto hurricane status, but reintensified to an 85kt CAT2 storm prior to this morning's landfall.  So far, 11 deaths have been blamed on Dean throughout the Caribbean and Central America.  It spent 4 full days as a major hurricane, which is nearly the normal SEASONAL total of "intense hurricane days".

The strip in the Caribbean along Dean's path is now 1-3C cooler than it was a week ago, a feature refered to as a "cold wake".  This happens for slow and/or intense storms, particularly over warm water that doesn't extend very deep.  The  monstrous waves do a lot of mixing, and although the top several meters might be very warm, the ocean is cooler below, and after an extreme mixing event (like a CAT4 hurricane), the cooler waters below are upwelled, leaving the cold wake.  This time of year, the waters can be quick to recover (perhaps a week or so).

http://einstein.atmos.colostate.edu/~mcnoldy/tropics/sectors/sst/carib15.php
That page shows a 15-day loop of SSTs in the Caribbean; areas with persistent cloudiness during that day do not have retrieved SSTs and are shown as white blotches.  You can easily track the cloudiness associated with Dean across the Caribbean from the 17th-20th.

Please visit my tropical Atlantic headquarters.

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