Hanna (2002)

Hanna formed in the central Gulf of Mexico from a tropical wave interacting with an upper‑level low and a surface trough. A well-defined low‑level circulation was identified just before 0000 UTC on 12 September 2002 about 250 nautical miles south of Pensacola, Florida. The system became a tropical storm at 0600 UTC 12 September and moved erratically—initially northeast, then southwest and west—before turning north ahead of an approaching trough. Hanna accelerated northward on 14 September and dissipated by 1800 UTC 15 September after crossing southern Alabama. Its center passed near the extreme southeastern tip of Louisiana before moving onshore along the Alabama–Mississippi border.

Hanna made two coastward landfalls on 14 September. The first occurred near the mouth of the Mississippi River at about 0800 UTC and the second near the Alabama–Mississippi state line near 1500 UTC. At both landfalls the storm’s maximum sustained winds were about 50 knots (near tropical storm strength) and the circulation was already becoming exposed and elongated as the storm moved inland.

The storm’s peak intensity was estimated at 50 knots (about 58 mph) with a minimum central pressure near 1001 mb, reached around 0000 UTC 14 September when Hanna was roughly 60 nautical miles south of the mouth of the Mississippi River. Hanna remained a tropical storm at its peak; it weakened to a depression later on 14 September and dissipated on 15 September.

Storm surge and heavy rain affected several Gulf Coast locations. Gulfport Harbor, Mississippi, reported a storm tide (water level above mean sea level) of 5.1 ft, and other storm tide or surge reports ranged roughly 3–5 ft at locations including Dauphin Island, Mobile County, and areas of Florida’s Panhandle (Dauphin Island to Navarre Beach; Walton, Bay, and Gulf counties). Pensacola reported sustained winds to 47 kt with a gust to 59 kt, a storm tide around 3.4 ft at Pensacola, and rainfall totals of several inches across the region. The heaviest rainfall totals from Hanna’s eastern semicircle were inland in the Southeast; Donalsonville, Georgia, reported the highest storm total at 15.56 inches, and many sites in Georgia and Florida reported 5–10 inches.

Hanna directly caused three deaths by rip currents along Florida’s Panhandle: one drowning at Pensacola Beach on 14 September and two others at Seagrove Beach (Walton County) and Panama City Beach (one on 14 September, one on 15 September). Overall damage was relatively limited and estimated near $20 million. Notable impacts included minor beach erosion from Dauphin Island, AL, to Navarre Beach, FL; storm tide flooding on Dauphin Island and in Mobile County; and significant freshwater flooding and crop losses in southwest Georgia (about $19 million in agricultural damage, primarily cotton and peanuts) with roughly 250 homes and 50 businesses damaged by flooding in Donalsonville.

Forecasts tended to bring Hanna north to the coast faster than it actually moved early in its life, so average official track errors for this storm were larger than the 1992–2001 mean. Intensity forecasts, however, were accurate in predicting little strengthening. A tropical storm watch and later warnings were issued in time for the first landfall: a tropical storm watch was issued at 1500 UTC 12 September and a tropical storm warning at 0900 UTC 13 September.