Bonnie (2004)

A tropical wave that moved off Africa on 29 July organized into a tropical depression about 360 nautical miles east of Barbados on 3 August. The system lost its surface circulation while crossing the eastern Caribbean but regenerated into a depression about 100 nmi southeast of western Cuba on 8 August. It strengthened to Tropical Storm Bonnie near the northeastern tip of the Yucatán Peninsula on 9 August, moved north then northeast across the Gulf of Mexico, and weakened under wind shear after 11 August. Bonnie became a remnant low just south of Cape Cod on 14 August, ending its life as a tropical cyclone.

Bonnie made its only U.S. tropical-cyclone landfall in the vicinity of St. Vincent and St. George Islands just south of Apalachicola, Florida on 12 August (listed as 1400 UTC in the best track table). At landfall the storm was a tropical storm with maximum sustained winds around 40 mph (best track gives 40 kt at the 12/1400 landfall entry) and a central pressure near 1002 mb. After landfall Bonnie weakened to a depression and moved northeast across the eastern United States.

The storm’s peak intensity occurred on 11 August when Bonnie reached maximum sustained winds of 55 knots (about 63 mph) and a minimum central pressure near 1001 mb, corresponding to a strong tropical storm (not a hurricane). Aircraft and satellite data showed Bonnie had a very small circulation at times, with an observed eyewall only about 8 nautical miles in diameter when it regenerated near the Yucatán.

Storm surge and heavy rain were limited but locally notable along the Florida Gulf coast. Reported storm surge values included about 2.7 ft at Apalachicola and about 1.9 ft at Cedar Key (storm tide values were larger, e.g., 5.21 ft recorded at Cedar Key). Rainfall totals included 3.22 inches at Cross City, 3.11 inches at Perry, and station reports such as 0.12 inch at Gainesville; an unofficial report at Alligator Point indicated 1.35 inches. Buoys and coastal stations measured sustained winds and gusts, with buoy 42039 reporting gusts up to 47 kt.

There were three fatalities in Pender County, North Carolina, attributed to a tornado spawned by Bonnie; these are reported as deaths associated with the storm (the report lists them without distinguishing direct vs indirect). Damage from Bonnie itself was generally limited compared with stronger storms, with the most significant impacts in portions of the southeastern United States from tornadoes and localized coastal flooding.

Noteworthy items: Bonnie had a complicated life cycle—forming, weakening to a wave, then regenerating—and it maintained a very small circulation at peak intensity. Forecast track errors were below the 1994–2003 average at short ranges (12–36 h) but much larger than average at 96–120 h for this storm. A tornado outbreak in the southeastern U.S. was associated with Bonnie.