Meteorological History of Hurricane Gustav - Interaction With Haiti and Jamaica

Interaction With Haiti and Jamaica

After making landfall near Jacmel, Hurricane Gustav began traversing northwestward across the mountainous terrain of southwestern Haiti, dumping heavy rains as it passed. With favorable atmospheric conditions the storm maintained its hurricane intensity for several hours after landfall, but the high mountains over which it was traveling disrupted its lower level circulation. The eye because ragged and clouded over as Gustav weakened to a tropical storm. A large mid- to upper-level anticyclone over the Florida Straight slowed Gustav's movement, holding it over the northern coast of Haiti's southern peninsula. Rainfall from the storm, which had been heavy since its landfall, began to accumulate as the storm's movement stalled. Although the storm's upper levels began experiencing moderate shear, and although parts of its circulation were still interacting with the mountains of southwestern Haiti, enough of Gustav's convection was over the Gulf of Gonâve that on the morning of August 27 its organization started to improve. That afternoon, as a broad ridge extended from the Gulf of Mexico into the western Atlantic Ocean, Tropical Storm Gustav began to slowly pull to the west, away from the island of Hispaniola. Increased shear weakened the storm as the building ridge to the north of Gustav imparted a southerly component to the storm's motion.

Northeasterly shear inhibited convection in the northeast quadrant, breaking up the storm's existing center. The storm's center reformed to the south, east of Jamaica, around a flare of deep convection. This new center was a little stronger than its previous one, and Gustav began moving southwest toward Jamaica. With its southerly reformation Gustav had moved itself away from the mountains of Haiti and over the warm waters of the Caribbean Sea. Finding itself in a much more advantageous environment, Gustav restrengthened to 70 mph (110 km/h). Continuing west under influence of the same mid-level ridge that had dominated its steering thus far, Gustav approached Jamaica and its outer bands delivered heavy rains. Unwavering in its westward motion, Gustav made landfall on Jamaica's eastern tip on August 28 at 1800 UTC at just below hurricane strength. It then moved across Jamaica, with its center on the southern coast, and its convection dragging across the island's mountainous center. Fifteen hours after making landfall, Gustav's center moved off the island's west coast and back over the Caribbean Sea. Unlike its Haitian landfall, Gustav's interaction with Jamaica did not disturb its structure. As it left the island on the morning of August 29, the storm's diameter increased substantially and prominent banding features developed. Its low-level center reorganized over the open water and with little wind shear a strengthening pattern emerged which quickly returned Gustav to hurricane status that afternoon.