Hurricane Lenny was the strongest November Atlantic hurricane since the 1932 Cuba hurricane. It was the sixteenth tropical cyclone, twelfth named storm, eighth hurricane, and record-breaking fifth Category 4 hurricane in the 1999 Atlantic hurricane season. Lenny formed on November 13 in the western Caribbean Sea at around 18:00 UTC and went on to form and maintain an unusual and unprecedented easterly track for its entire duration, which gave it the common nickname, "Wrong Way Lenny". It attained hurricane status south of Jamaica on November 15 and passed south of Hispaniola and Puerto Rico over the next few days. Lenny rapidly intensified over the northeastern Caribbean on November 17, attaining peak winds of about south of Saint Croix in the United States Virgin Islands. It gradually weakened while moving through the Leeward Islands, eventually dissipating on November 23 over the open Atlantic Ocean.

Before moving through the Lesser Antilles, Lenny produced rough surf that killed two people in northern Colombia. Strong winds and rainfall resulted in heavy crop damage in southeastern Puerto Rico. 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. Damage in the United States territories totaled about $330 million. The highest precipitation total was at the police station on the French side of Saint Martin. On the island, the hurricane killed three people and destroyed more than 200 properties. In nearby Antigua and Barbuda, the hurricane killed one person; torrential rainfall there contaminated the local water supply. Significant storm damage occurred as far south as Grenada, where high surf isolated towns from the capital city.

Meteorological history

Hurricane Lenny began as a low-pressure area that was first observed in the southwestern Caribbean Sea on November 8. It developed an area of convection but remained poorly defined for the next few days. Thunderstorms spread across the region, producing heavy rainfall in portions of Mexico and Central America. On November 13, the system became better organized; a Hurricane Hunters flight later that day discovered a surface circulation and winds of about . The data indicated the development of Tropical Depression Sixteen at 1800 UTC, about south of the Cayman Islands. The depression's convection was fairly disorganized, and the National Hurricane Center (NHC) did not anticipate any strengthening for three days. For much of its existence, the tropical cyclone maintained a track from west to east across the Caribbean Sea, which was unprecedented in the Atlantic hurricane database, earning it the nicknames "Left-Hand Lenny" and "Wrong Way Lenny". The path resulted from its movement along the southern end of a trough over the western Atlantic Ocean.

After its formation, the depression gradually became better organized; the NHC upgraded it to Tropical Storm Lenny on November 14, based on reports from the Hurricane Hunters. When it was first upgraded to a tropical storm, the cyclone already had winds of and a developing eye feature. At 0000 UTC on November 15, Lenny attained hurricane status about southwest of Kingston, Jamaica. The quick intensification was unexpected and occurred after a large area of convection blossomed over the center. At the same time, Lenny developed an anticyclone aloft, which provided favorable conditions for the hurricane's development. After moving east-southeastward during its initial development stages, the hurricane turned more to the east on November 15. The Hurricane Hunters reported winds of , which indicated that Lenny had become a Category 2 on the Saffir-Simpson scale. However, the cloud pattern subsequently became less organized as the eye disappeared, and Lenny's winds weakened to while the hurricane passed south of Hispaniola. The NHC noted the deterioration could have been due to a disruption of the storm's small inner core by "subtle environmental changes". After the sudden weakening, the Hurricane Hunters reported that the eye had reformed and the hurricane's winds had reached . At the time, a ridge was expected to build to Lenny's east and turn the storm northeastward into Puerto Rico 24 hours later.

Beginning on November 16, Hurricane Lenny underwent a 24-hour period of rapid deepening, reaching major hurricane status about south of the Mona Passage. It developed well-defined banding features, good outflow, and a circular eye that was visible from the radar in San Juan, Puerto Rico. The hurricane continued to become better organized, with an eye in diameter surrounded by a closed eyewall. Around 1200 UTC on November 17, Lenny intensified into a Category 4 hurricane while approaching the islands of the northeastern Caribbean. It was the fifth storm of such intensity in the year, setting the record for most Category 4 hurricanes in a season. The hurricane then made its closest approach to Puerto Rico, passing about southeast of Maunabo. Shortly thereafter, Lenny attained peak winds of while passing south of the island of Saint Croix in the United States Virgin Islands. This made it the fourth-strongest hurricane on record to form during the month of November. Hurricane Hunters reported Lenny's peak winds in the southeastern portion of the hurricane; the group also reported a minimum pressure of 933 mbar, a drop of 34 mbar in 24 hours. In addition, a dropsonde recorded winds of while descending to the surface, the highest dropsonde wind speed recording in a hurricane at the time.

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. Late on November 18, Lenny's eye moved over Saint Martin with winds of . After continued weakening, the hurricane struck Anguilla and Saint Barthélemy the next day. It turned southeastward while still drifting, bringing heavy rainfall and strong winds to the islands across the northeastern Caribbean. Late on November 19, Lenny weakened to tropical storm intensity after increased wind shear exposed the cyclone's center from the deepest convection. Early on November 20, the storm made landfall on Anguilla, although by then the center had become difficult to locate. Later that day, the cyclone exited the Caribbean, continuing its southeast track. On November 21, Lenny turned to the northeast and weakened to a tropical depression. The deep convection was located at least east of the increasingly elongated center. Lenny turned to the east for the final time early on November 22, dissipating on the next day about east of the Lesser Antilles.

Preparations

Early in Lenny's existence, a tropical storm warning and hurricane watch were issued for Jamaica. Later, a hurricane watch was issued for the southern coast of Hispaniola, and a tropical storm warning was also issued for the Dominican Republic. Haitian officials declared a state of alert in three southern provinces and allocated about $1 million (1999 USD) in hurricane funds. Residents in flood-prone areas were advised to evacuate in southern Haiti and in the neighboring Dominican Republic.

A hurricane watch was issued for Puerto Rico and the Virgin Islands late on November 15, which was upgraded to a hurricane warning six hours later. By that time, Lenny was projected to move over Puerto Rico. After Lenny made its closest approach to the island, the hurricane warning was downgraded to a tropical storm warning on November 17, which was discontinued the following day along with the advisories in the Virgin Islands. In Puerto Rico, the media maintained continuous coverage on the hurricane based on statements and warnings from the San Juan National Weather Service office. Based on the coverage, the public was well informed of the hurricane's threat to the island. Before the storm and as a result of its impact, around 4,700 people evacuated to 191 shelters. This included 1,190 residents in Ponce who evacuated to 27 schools, as well as 584 people in western Puerto Rico. Officials closed all schools, banned the sale of alcohol, and ordered a freeze on the price of emergency supplies. The Federal Emergency Management Agency (FEMA) activated six medical assistance teams, three medical support teams, and two advance medical assessment units. The agency stored five days' worth of food in schools in the U.S. Virgin Islands. Before the hurricane's arrival, U.S. Virgin Islands governor Charles Wesley Turnbull declared a state of emergency. In St. Croix, 309 people rode out the storm in shelters. Officials opened eight shelters in the British Virgin Islands. There, airlines and hotels assisted in evacuating tourists from the area.

Governments across the eastern Caribbean issued hurricane warnings as far south as Montserrat. In Anguilla, residents near the coast were advised to evacuate. Schools closed ahead of the storm, and the ferry between the island and Saint Martin was halted and moved to a safe location. In Saint Kitts and Nevis, the National Emergency Management Agency was activated on November 16. Officials there advised residents living near ghauts to evacuate, and one shelter was located in each district of the country. In addition, stores were open for longer hours to allow people to stock up on supplies. Most businesses and schools were closed in Antigua and Barbuda during the storm, while in Dominica, the airport was closed. Further south, there was little warning for the hurricane in Grenada, and most people left their boats in the water.

Impact +Impact by country or region County/Region Deaths Damage Source Colombia 2 unknown Antigua and Barbuda 1 $51.3 million Guadeloupe 5 $100 million Dominica 0 $21.5 million Saint Kitts and Nevis 0 $41.4 million Saint Martin 3 $69 million Martinique 1 unknown Saint Lucia 0 $6.6 million Puerto Rico 0 $105 million U.S. Virgin Islands 0 $225 million British Virgin Islands 0 $5.6 million Others 5 Total 17 ~$785.8 million

Across the eastern Caribbean, Hurricane Lenny damaged vital infrastructure, including roads and piers in the tourism-dependent islands. Most of the islands' tourism areas were on western-facing beaches, many of which were unprepared for the high waves and winds produced by Lenny.

Central Caribbean Early in its existence, Lenny produced large waves and high tides along the Guajira Peninsula in Colombia, sinking two boats and flooding 1,200 houses. There were also reports of flooded businesses and damaged crops. In the country, strong winds on the storm's fringe killed a man by striking him with a beam. Although there were initial reports of nine people missing, only two were counted in the death toll for mainland Colombia. Two sailors were killed offshore when their yacht was lost in the southern Caribbean Sea.

Along the ABC Islands off the north coast of Venezuela, the hurricane produced waves along the southwest coastlines. The waves caused heavy beach erosion and coastal damage to properties and boats.

In Jamaica, the hurricane dropped heavy rainfall but left little damage. Rains in the Dominican Republic caused flooding in the country's southwest portion. 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.