On September 1, a strong tropical wave moved over the Atlantic from the west coast of Africa, producing a large area of vigorous thunderstorms near the coast as it did so. The system steadily gained organization as it moved westward at a fairly fast pace. A low pressure center formed on September 4 and the circulation became well-defined enough to designate the system Tropical Depression Thirteen on September 5. Very high sea surface temperatures in the tropical Atlantic allowed the storm to intensify quickly from that point as it moved west-northwestward. It became Tropical Storm Lee six hours after formation and developed prominant spiral banding almost immediately. Some slight northeasterly shear was not enough to prevent it from becoming a category 1 hurricane by the evening of September 6.
Conditions became even more favorable on September 7 and Lee's structure improved rapidly. The nascent eyewall, which was open to the west in the morning, closed off quite quickly after that and the stage was set for the hurricane to deepen at an incredible pace. The eye cleared out and became symmetric by the evening and Lee strengthened to a category 4 hurricane. That evening, Lee reached its peak intensity as a powerful category 5 hurricane, with maximum winds of 165 mph and a central pressure of 926 mb. These winds were the highest recorded in any Atlantic hurricane since Dorian of 2019. Shortly after that, wind shear disrupted the center of Lee and it began a weakening trend on September 8. The eye clouded over and the central dense overcast eroded, particularly on the west side. This brought the storm back down to a category 3 as it made its closest approach to the northeasternmost Caribbean islands.
Lee maintained its steady west-northwest heading, though its forward speed gradually slowed. The weakening halted on September 10, by which time the storm was a category 2. Its structure subsequently improved, though not to the level of its original burst of intensification. Lee regained major hurricane status that day. Further increases in winds were precluded by the storm's inner core organization, which consisted of a very large outer eyewall and a decaying partial inner eyewall. However, even though the winds did not increase further, the hurricane-force wind field had expanded significantly and continued to grow over the next few days.
By September 11, the storm had turned northwest and slowed further. Its path brought it well northeast of the Bahamas, though the large circulation caused large swells and rip currents to the Caribbean islands and U.S. east coast. Lee also traveled over the cool wake in ocean temperatures left behind by Franklin and exacerbated that issue by upwelling cool waters with its slow forward motion. As a result, a slow weakening began on September 13. The storm turned toward the north that day under the influence of an approaching trough. On September 14, Lee dropped to category 1 intensity and made its closest approach to Bermuda, passing well to the west. Regardless, the storm's large windfield brought a sustained period of tropical storm conditions to the island.
On the 15th, the cyclone became significantly less tropical in appearance, with dry air invading the southern semicircle and displacing convection northward. That evening, tropical storm conditions began across a wide area of coastal New England and Atlantic Canada. Early on September 16, Lee completed extratropical transition. Nevertheless, post-tropical Lee still brought winds to near hurricane force to Nova Scotia when it made landfall in the easternmost part of the province later that day. The center of the storm crossed the Bay of Fundy and made another landfall in New Brunswick very early on September 17. Weakening more quickly, ex-Lee moved over the Gulf of St. Lawrence and finally over Newfoundland on the way out to sea.
The image above shows Lee as a category 5 hurricane. Just after this satellite imagery, mid-level shear from the southwest disrupted the center and weakened the storm. The beginnings of this disruption are already apparent in the image.
Lee did not made landfall as a tropical cyclone but did have direct impacts on Atlantic Canada after becoming post-tropical.
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