The 19th named storm of the 2005 Atlantic hurricane season, Tammy formed on October 5 off the east coast of Florida from the interaction of a tropical wave and a trough.

Tammy moved into the U.S. state of Georgia, degenerating into a remnant low pressure area, which was absorbed by an extratropical cyclone over the eastern Gulf of Mexico.

The wave moved across the Atlantic without any development until October 2, when it started to interact with a mid- to upper-level large trough north of the Lesser Antilles.

The system produced an area of convection, or thunderstorms, which spawned a surface trough, although it failed to organize at first due to strong wind shear.

[1] On October 4, the central pressure dropped as the trough approached the east coast of Florida, toward an area of lower wind shear.

[2][1] Early on October 5, a circulation developed within the convection, leading to the formation of Tropical Storm Tammy just 23 mi (37 km) east of Jupiter, Florida.

The National Hurricane Center (NHC) immediately designated Tammy as a tropical storm due to the presence of gale-force winds.

Based on observations from a reconnaissance flight, as well as two nearby ships, the NHC estimated that Tammy strengthened to attain peak winds of 50 mph (85 km) late on October 5.

On October 7, the remnants of Tammy were absorbed by an extratropical low over the eastern Gulf of Mexico, which was attached to a cold front that moved up the east coast of the United States over the next two days.

[6] The U.S. Department of Homeland Security's U.S. Coast Guard, 7th District issued an advisory to mariners, warning them to prepare for the storm and avoid the ocean if possible.

The Glynn County Emergency Operations Agency monitored and prepared for Tropical Storm Tammy's landfall, however the poor warning hampered their efforts.

[12] Lightning produced by a thunderstorm in Broward County, Florida struck three teenagers during a football game in Coconut Creek, killing one and injuring the other two.

[18] Tammy's storm surge was approximately 2 to 4 ft (0.61 to 1.22 m) and caused salt-water flooding along the coast of northeastern Florida, Georgia, and South Carolina.

[20] Rated an F0 tornado, it touched down near Brunswick, Georgia where it snapped trees and caused moderate roof damage along its 2 mi (3.2 km) path.

[1] The outer bands of Tammy brought heavy rains, peaking around 7 in (180 mm) in places,[22] and caused significant beach erosion.

[41] Shrimpers in the Carolinas blamed high fuel prices and the disruption of Tropical Storm Tammy for some of the troubles facing the shrimping industry in 2005.

Rising fuel prices and dwindling demand has already created tough conditions that year, but the disruption of several days' fishing due to Tammy escalated the situation.

[46][47][32] Two years after the floods destroyed several mobile homes in Greenfield, Massachusetts, the city purchased the land and turned it into protected greenspace, using state and federal funds.