Storm Lifecycle

A vigorous tropical wave moved off the west coast of Africa in the second week of August. It quickly organized itself and formed into a low on August 12. Tropical Depression Four formed on August 13 in the eastern Atlantic from a tropical wave to the south of Cape Verde. The depression was already exhibiting persistent deep convection, albeit confined to the western portion of its circulation due to easterly wind shear. The depression was expected to strengthen significantly over the coming days due to abating wind shear and warming sea surface temperatures which created conditions favorable for tropical intensification. More » The depression moved briskly westward, south of a deep layered ridge, quickly escaping the easterly shear. Based on satellite images and microwave and QuikSCAT data, the depression was upgraded to Tropical Storm Dean on August 14. The storm continued to strengthen overnight as it gained organization, and on August 16 it was upgraded to the first hurricane of the 2007 season. On August 17 the eye of the hurricane passed into the Caribbean between the islands of Martinique and Saint Lucia as a Category 2 hurricane. In the warm waters of the Caribbean Dean rapidly strengthened into a Category 4 hurricane. The National Hurricane Center upgraded Dean to Category 5 status late on August 20 and at that strength it made landfall on the Yucatan Peninsula of Mexico near Costa Maya on August 21. Dean weakened to a category one storm over land. At least 21 people have been killed by Hurricane Dean. Surprisingly, no deaths have been attributed to its first landfall, as a Category 5 hurricane, likely due to the fact that the landfall brought the heaviest storm surges onto sparsely-populated lands north of Chetumal Bay, including the Sian Ka'an Biosphere Reserve. « Hide