Initially, the depression's large size and moderate wind shear kept it from organizing, but it eventually intensified into Tropical Storm Teddy on September 14.

After steadily intensifying for about a day, the storm rapidly became a Category 2 hurricane on September 16 before westerly wind shear caused a temporary pause in the intensification trend.

Its large size and strength caused high waves and rip currents to impact areas hundreds of miles from its path, ranging from the Lesser and Greater Antilles to the East Coast of the United States and Atlantic Canada.

The National Hurricane Center (NHC) began to monitor a tropical wave over West Africa early on September 7.

[2][3] Though the wave was experiencing moderate northeasterly shear, convection increased early on September 12, which led to the development of a well-defined surface center and the formation of Tropical Depression Twenty around 06:00 UTC while the system was located about 575 mi (925 km) southwest of the Cabo Verde Islands.

[8] By 00:00 UTC, September 16, Teddy strengthened to become a category 1 hurricane while located about 805 mi (1,295 km) east-northeast of Barbados.

[4] Late that day, Teddy reached its peak intensity with maximum sustained winds of 140 mph (225 km/h) a minimum barometric pressure of 945 mbar (27.9 inHg).

[4] Teddy then moved over slightly cooler waters caused by upwelling from Hurricane Paulette, contributing to its weakening trend.

[11] Teddy passed about 230 mi (370 km) east of Bermuda on September 21 as it turned northward and north-northeastward while interacting with a negatively tilted trough.

Interaction with the trough also triggered the extratropical transition process; Teddy's wind field became more asymmetric, and the associated convection become less centralized.

[4] Just before this transition, the diameter of gale-force winds measured up to 850 mi (1,370 km) across from northeast to southwest, making Teddy the 4th largest Atlantic hurricane on record.

[12] At 12:00 UTC on September 23, the storm made landfall near Ecum Secum, Nova Scotia, with sustained winds of 65 mph (105 km/h).

[18] Large swells were generated by the storm, which affected the Lesser Antilles, the East Coast of the United States, Bermuda, and Atlantic Canada.

[19] One buoy operated by the National Oceanic and Atmospheric Administration (NOAA) in the open northern Atlantic off the coast of Nova Scotia reported a wave height of 35 feet (11 m) early on September 22.

[24] On September 18, a man and a woman drowned in the waters off La Pocita Beach in Loíza, Puerto Rico due to the rip currents and churning waves that Teddy had caused in the north of the Lesser and Greater Antilles.

[25][26] Charleston, South Carolina, experienced high tides topping out at major flood stage for three straight days from September 19–21.