Hurricane Lee was a long-lived and intense tropical cyclone which impacted Bermuda, the Northeastern United States, and Eastern Canada in September 2023.

Highly favorable conditions enabled Lee to rapidly intensify to a Category 5 hurricane on September 7, its winds increased by 80 mph (130 km/h) in 24 hours.

Just as quickly however, Lee's strength waned, and it fluctuated in intensity for several days on account of strong wind shear and multiple eyewall replacement cycles.

On September 13, the system rounded the southwest side of a large ridge of high pressure over the central Atlantic, turned, and accelerated northward.

The cyclone then made landfalls in Nova Scotia, New Brunswick, Prince Edward Island, and in Newfoundland and Labrador, before moving out into the far northern Atlantic on September 18, where it merged with another extratropical low.

Strong winds with hurricane‑force gusts caused extensive power outages in the U.S. state of Maine, and in the Canadian provinces of New Brunswick and Nova Scotia.

[2] The wave moved offshore into the tropical Atlantic Ocean on September 2,[3] producing disorganized shower and thunderstorm activity, and began to gradually organize.

[7] Lee tracked west-northwestward, steered by a mid-level ridge located to its north, and continued to intensify as it became better organized, with increased convective banding, development of a central dense overcast, and formation of a ragged eye, evident in visible satellite imagery by the following afternoon.

[11] A few hours later, a hurricane hunters mission into the storm found that it had reached Category 5 strength, and possessed a clear 17 mi-wide (28 km) eye surrounded by convective cloud tops with temperatures as low as −105 °F (−76 °C).

[17] Later that day, data from a hurricane hunters mission into the storm revealed that Lee was undergoing an eyewall replacement cycle and still being adversely affected by modest vertical wind shear.

[19] Lee's overall appearance improved in the short term, and surface barometric pressure dropped due to the storm growing in size, despite maximum sustained winds remaining relatively consistent.

[20] The system underwent two eyewall replacement cycles over the course of the next couple days; and while they caused some fluctuations in its size and intensity, Lee remained a major hurricane throughout.

[21][22] Lee slowly tracked west-northwestward to northwestward during this time, before turning northward on September 13, moving around the western side of a subtropical ridge situated over the central Atlantic.

[21][23][24] That same day, the hurricane began to encounter increasing southwesterly shear coupled with dry air entrainment and weakened to Category 2 strength.

[25] Slow weakening continued and Lee was downgraded to a Category 1 hurricane on the morning of September 14, as its eye was no longer apparent in satellite images and deep convection was absent over the southwestern portions of the storm circulation.

[27] As Lee pushed northward, continued dry air entrainment and increasingly strong southerly wind shear displaced the storm's convection to the northern side of the system, weakening it further.

[37] During the afternoon on September 14, a boat was capsized during a small craft advisory after being hit by a tall wave in New Jersey's Manasquan Inlet, requiring first responders to rescue two people.

[36] New York State Governor Kathy Hochul deployed fifty National Guard members to Long Island in preparation of the storm's arrival.

Healey also announced that 50 members of the Massachusetts National Guard capable of operating high-water vehicles were being activated in anticipation of any potential rescues.

[57] New Hampshire Governor Chris Sununu announced that utility crews were being staged across the state to quickly respond to power outages and warned residents to not be complacent.

In Bar Harbor, a whale watching vessel broke free and crashed ashore, forcing authorities to offload 1,800 U.S. gallons (6,800 L) of diesel fuel to prevent it from spilling into the ocean.

[72] On September 15, Prime Minister Justin Trudeau announced that he had convened the Incident Response Group to discuss potential impacts from the cyclone and warned Canadians to take precautions and listen to their local officials.

[73] Strong winds with hurricane‑force gusts caused widespread, but minimal damage in Nova Scotia and in New Brunswick as Lee passed through, mostly in the form of downed trees and power lines.

[74] On September 15, New Brunswick Emergency Measures Organization director Kyle Leavitt was joined by Premier Blaine Higgs and other officials in a press conference.