Lenny rapidly intensified over the northeastern Caribbean on November 17, attaining peak winds of 155 mph (249 km/h) about 21 mi (34 km) south of Saint Croix in the United States Virgin Islands.

Despite the hurricane's passage near Saint Croix at peak intensity, damage on the small island was only described as "moderate", although there was widespread flooding and erosion.

On November 13, the system became better organized; a Hurricane Hunters flight later that day discovered a surface circulation and winds of about 35 mph (56 km/h).

[1] After its formation, the depression gradually became better organized;[3] the NHC upgraded it to Tropical Storm Lenny on November 14,[1] based on reports from the Hurricane Hunters.

[6] However, the cloud pattern subsequently became less organized as the eye disappeared, and Lenny's winds weakened to 85 mph (137 km/h) while the hurricane passed south of Hispaniola.

At the time, a ridge was expected to build to Lenny's east and turn the storm northeastward into Puerto Rico 24 hours later.

[1] It developed well-defined banding features, good outflow, and a circular eye that was visible from the radar in San Juan, Puerto Rico.

[1] Around the time it peaked in intensity, Lenny's forward speed decreased in response to light steering currents between two ridges.

Despite favorable conditions for strengthening, the hurricane weakened as it turned to an eastward drift, possibly due to the upwelling of cooler waters.

[1] Late on November 19, Lenny weakened to tropical storm intensity after increased wind shear exposed the cyclone's center from the deepest convection.

[1] Haitian officials declared a state of alert in three southern provinces and allocated about $1 million (1999 USD) in hurricane funds.

[1] In Puerto Rico, the media maintained continuous coverage on the hurricane based on statements and warnings from the San Juan National Weather Service office.

Schools closed ahead of the storm, and the ferry between the island and Saint Martin was halted and moved to a safe location.

[27] Across the eastern Caribbean, Hurricane Lenny damaged vital infrastructure, including roads and piers in the tourism-dependent islands.

[29] Early in its existence, Lenny produced large waves and high tides along the Guajira Peninsula in Colombia,[1] sinking two boats and flooding 1,200 houses.

[19] Flooding around Les Cayes in southwestern Haiti destroyed 60 percent of the rice, corn, and banana plantations, while high waves wrecked several houses in Cavaellon.

Rainfall in the days prior to Lenny's approach left areas susceptible to flooding, which caused many rivers in the northeastern portion of the island to overflow their banks following the storm.

In Frederiksted, the hurricane produced a storm surge of 15–20 ft (4.6–6.1 m)[1] along with high waves that washed out roads and damaged coastal structures.

[1] The highest precipitation related to the storm occurred at the police station on the French side of Saint Martin, where a total of 34.12 in (867 mm) was recorded.

[1] Due to the hurricane's unusual track from the west, it produced unparalleled waves of 10–16 ft (3.0–4.9 m) along the western coast of St. Martin,[31] which damaged or destroyed many boats.

[1] During its passage, Lenny left widespread damage to the infrastructure, including to the airport, harbor, resorts, power utilities, schools, and hospitals.

[1] Although there were no tropical-storm sustained wind recorded as the storm didn't really impacted the islands unlike previous hurricanes such as Luis, Marilyn and Georges, the extent of damage was globally heavier due to the unusual high waves in the western portion of the island and the very slow-moving storm that generated unrelated flooding inland in Grande-Terre for a 48 hour-period.

In Dominica, high waves damaged the island's western coastal highway, leaving the most heavily traveled road temporarily closed.

[49] In western Grenada, high waves affected much of the coastline,[29] destroying 21 small boats and causing significant beach erosion.

The erosion heavily impacted tourist areas and also threatened the foundation of the runway at the Maurice Bishop International Airport.

[29] In Saint John Parish, the storm knocked out the water and power supply and forced several families to evacuate their damaged houses.

This allocated federal funding for loans to public and private entities and provided 75 percent of the cost of debris removal.

[29] In response to the damage on Saint Martin, officials in the Netherlands Antilles issued an appeal to the European Parliament for assistance from the international community.

With a loan from the Caribbean Development Bank, the government worked to complete a sea wall along a highway south of its capital Roseau.

In Grenada, workers repaired the road system to allow fuel transportation across the island and began to reclaim land near its airport to mitigate erosion.