Fujiwhara effect
A cold front moved offshore New England and Atlantic Canada around September 7. A low-pressure area developed along the front three days later and reached gale-force intensity by early on September 12. After a curved band of convection formed later that day, the low became Subtropical Storm Joyce by 12:00 UTC while centered roughly west-southwest of Flores Island in the Azores. From September 13-September 14, Joyce interacted with the larger Hurricane Helene, due to the Fujiwhara effect, with Joyce being steered counter-clockwise around Helene. At 00:00 UTC on September 14, Joyce transitioned into a tropical storm. Later that day, Joyce began turning eastward and reached its peak intensity with sustained winds of 50 mph (85 km/h). Afterward, Joyce began to weaken due to the increasing wind shear. At 12:00 UTC on September 16, Joyce weakened into a tropical depression. At 00:00 UTC on September 19, Joyce degenerated into a remnant low, which continued an eastward motion for another couple of days, before dissipating late on September 21.