Nearly all forecasting agencies predicted above-average activity during the season, due to expectations of abnormally warm sea surface temperatures, the unlikelihood of an El Niño, and the possibility of a La Niña.

[4] Prior to the start of the season, NOAA deployed five modified hurricane-class saildrones at key locations around the basin, and in September, one of the vessels was in position to obtain video and data from inside Hurricane Sam.

[31] Each season dating back to 2016 recorded ACE index values exceeding 129, which senior research associate Brian McNoldy of the University of Miami described as "unprecedented even for four years, let alone six!

[55] Short-lived Victor developed late in the month at an unusually low latitude of 8.1°N,[56] tying Kirk in 2018 and behind only an unnamed 1902 hurricane (7.7°N) for the southernmost location in which an Atlantic system has reached tropical storm intensity.

This system became co-located with an upper-level low, reducing wind shear and causing atmospheric instability, which allowed convection to develop despite cold sea surface temperatures.

This low, and the associated convection, became better defined while being directed northeast by a shortwave trough, and a tropical depression formed about 125 mi (200 km) east-southeast of Cape Fear, North Carolina, around 06:00 UTC on June 14.

Banding features became better defined, especially across the northern and western quadrants of the storm, and Bill reached peak winds of 65 mph (105 km/h) early on June 15 while paralleling the Northeast United States coastline.

Its northeast track soon brought the system over colder waters and into higher wind shear, resulting in Bill's transition to an extratropical cyclone approximately 370 mi (595 km) east-southeast of Halifax, Nova Scotia, around 00:00 UTC on June 16.

Around 00:00 UTC on June 19, the system organized into Tropical Storm Claudette and promptly moved onshore about 30 mi (48 km) south-southwest of Houma, Louisiana, with peak winds of 45 mph (72 km/h).

[35] The precursor Central American gyre, which also contributed to the development of Tropical Storm Dolores in the eastern Pacific, brought flooding to portions of Mexico, especially in Oaxaca, Puebla, and Veracruz.

By June 27, the trough developed a closed low-level circulation as it continued to track west-northwestward, and it is estimated that Tropical Depression Four formed by 18:00 UTC that day about 460 mi (740 km) east-southeast of Charleston, South Carolina.

[62] The storm produced rainfall totals of up to 3 in (76 mm) in parts of South Carolina in a matter of hours following its landfall, causing minor flash floods in populated areas.

Thereafter, favorable conditions allowed Elsa to briefly re-attain hurricane status early on July 7, before wind shear and dry air entrainment weakened the system back to a tropical storm six hours later.

At 18:00 UTC on August 16, Fred peaked with winds of 65 mph (105 km/h) and a minimum pressure of 993 mbar (29.3 inHg), just over an hour before making landfall near Cape San Blas, Florida.

Tracking quickly westward, the system acquired sufficient convective organization and a surface circulation, and thus, it became a tropical depression at 06:00 UTC on August 13, approximately 1,015 mi (1,635 km) east of the Leeward Islands.

The storm's second landfall in Mexico left significant impact in Hidalgo, Puebla, and Veracruz, with 110,000 homes damaged in the three states combined due to flooding, mudslides, and strong winds.

[43] In the Northeastern United States, the system produced tides that left water up to 2 to 4 ft (0.61 to 1.22 m) above-ground in coastal Connecticut and the north side of Long Island in New York.

[44] As Ida's precursor tropical wave passed near the westernmost Leeward Antilles, it began to interact with a broad area of low pressure located along the northern coast of South America, triggering damaging floods and landslides across Venezuela, leading to 20 deaths.

After decelerating and curving northwestward due to a weakness in the subtropical ridge, the system organized into a tropical depression at 06:00 UTC on August 28 while situated approximately 805 mi (1,295 km) east of the Leeward Islands.

A temporary burst in convection allowed the depression to intensify into Tropical Storm Kate early on August 30 and soon peaked with winds of 45 mph (72 km/h) and a minimum pressure of 1,004 mbar (29.6 inHg).

Although wind shear left convection displaced to the northeast of Julian's center, seas remained warm, allowing some intensification as the storm headed rapidly northeastward due to an approaching cold front.

While crossing the Labrador Sea later that day, the storm transitioned into a post-tropical cyclone, which was subsequently absorbed by a larger extratropical system by early on September 12 about halfway between Newfoundland and Greenland.

[47] Rough surf and rip currents generated by Larry's large wind field led to five drownings, one each in the U.S. Virgin Islands, Puerto Rico, South Carolina, Florida, and Virginia.

By 00:00 UTC on September 19, the disturbance had acquired a well-defined circulation and enough organized deep convection for it to be designated a tropical depression around 375 mi (605 km) south-southwest of the Cabo Verde Islands.

Despite wind shear and dry air impacting the depression's eastern quadrants,[53] satellite images showed that the deep convection increased within the cyclone and that its overall structure continued to improve,[91] with the system becoming Tropical Storm Rose late on September 19.

Thereafter, very low wind shear and warm waters allowed Sam to reach hurricane status about 24 hours later as it tracked westward to west-northward along the eastern periphery of a mid-tropospheric anticyclone.

Satellite images showed a well-defined eye embedded in a developing central dense overcast, and following an increase in Dvorak intensity estimates, Sam became a Category 4 hurricane late on September 25.

[54] The NHC estimated that the cyclone reached its peak intensity around 18:00 UTC on September 26, with the storm likely attaining maximum sustained winds of 155 mph (250 km/h) and a minimum barometric pressure of 927 mbar (27.4 inHg), making Sam a high-end Category 4 hurricane.

As this front interacted with an upper-level low moving in from the west, it generated an area of disturbed weather, with increasing convection located near a developing surface center.

[58] By November 7, Wanda had lost its deep convection and became a post-tropical low at 12:00 UTC about 430 mi (690 km) west-northwest of the westernmost islands of the Azores, several hours before merging with a frontal system.