Hurricane Hanna (2008) - Meteorological History

Meteorological History

During late August 2008, a tropical wave emerged off the coast of Africa and tracked westward across the Atlantic Ocean. After several days, an associated area of low pressure gained deep convection and organization. On August 28, while to the east-northeast of the northern Leeward Islands, the low formed into Tropical Depression Eight. Later that day, it attained tropical storm status, and as such was named Hanna by the National Hurricane Center. At the time, the low-level center of circulation was partially exposed on the western edge of the convection, indicating westerly wind shear.

Tracking westward primarily under the steering current of a large ridge to the north, the convective pattern began to redevelop late on August 28. Since forecast, models predicted the storm would weaken and move southwestward due to outflow associated with nearby Hurricane Gustav. Despite this, the storm began entering a favorable environment, and was forecast to intensify. An upper-level low that had been producing wind shear moved away from the system, though light shear continued. At the same time, the low-level center once again became separated from the convection, which was primarily confined to a cyclonic banding feature in the eastern half of the circulation. It remained weak as it moved erratically westward while east of the Bahamas on August 30. Due to the influence of Hurricane Gustav's large circulation, Hanna suddenly took a sharp southerly turn and slowed down to drift while located to the north of the Turks and Caicos Islands. On September 1, as Hanna drifted to the south-southwest, convection increased and the storm began to intensify. Later that day around 1:30 pm EDT, an Air Force Reconnaissance Aircraft found winds within Hanna supportive of hurricane strength, and the National Hurricane Center upgraded Hanna to a hurricane. Early on September 2, strong wind shear in association with Hurricane Gustav began to affect Hanna and the storm was downgraded to a tropical storm on September 3.

Early on September 6, 2008, Hanna made landfall near the South Carolina-North Carolina border. The system became an extratropical cyclone as it moved into Atlantic Canada early on September 7 and raced across the North Atlantic, sweeping west of Great Britain on September 10 before turning north and becoming absorbed by a stronger extratropical cyclone between Iceland and Greenland late on September 12.