1999–2000 South-West Indian Ocean cyclone season
The same monsoon trough that spawned Connie also produced an area of convection southeast of Diego Garcia on January 28. The circulation slowly organized, and the MFR classified it as a tropical disturbance on January 30. A nearby trough steered the system southeastward initially and later to the southwest. On January 31, the system became a tropical depression, and later Moderate Tropical Storm Damienne the next day, reaching peak winds of 65 km/h (40 mph). Also on February 1, the JTWC initiated warnings on Tropical Cyclone 10S, which estimated 1‑minute winds of 95 km/h (60 mph). Increased wind shear removed the convection on February 2, causing marked weakening, and prompting the JTWC to discontinue advisories that day. This was despite forecasts of strengthening to near tropical cyclone status. As a weak tropical disturbance, Damienne turned to a rapid westward motion, passing north of Rodrigues and Tromelin. The circulation dissipated on February 7 off the northeast coast of Madagascar.
On February 1, a low-pressure area formed within the monsoon trough to the south of Indonesia, which would eventually become Tropical Cyclone Leon in the Australian basin, as well as Tropical Cyclone 11S according to JTWC. The storm tracked westward across much of the Indian Ocean, fluctuating in strength due to changes in the atmosphere. After crossing 90° E, the MFR began tracking the system as Tropical Storm Eline on February 8. The storm continued westward across the Indian Ocean and intensified greatly as it approached the east coast of Madagascar. Late on February 17, Eline made landfall near Mahanoro with 10‑minute winds of 165 km/h (105 mph), making it the strongest storm to hit the country in several decades. The storm rapidly weakened over land, but restrengthened in the Mozambique Channel to reach peak 10‑minute winds of 185 km/h (115 mph). On February 22, Eline made landfall about 80 km (50 mi) south of Beira, Mozambique near peak intensity and quickly weakened over land. The well-defined circulation moved across southern African, finally dissipating over eastern Namibia on February 29. Throughout its duration, Leon–Eline lasted 29 days, a record longevity for a storm in the south-west Indian Ocean. The track was over 11,000 km (6,800 mi), or about 25% of the Earth's circumference.
1998–99 South-West Indian Ocean cyclone season
During an extended period of quiet conditions across much of the basin, an area of low pressure persisted along the eastern coast of Mozambique. Convection fluctuated daily but became more persistent on February 11. That day, the thunderstorms organized into a circulation that had formed less than southeast of Beira, Mozambique, becoming Tropical Disturbance D1. After forming, the system moved southward, developing a central dense overcast with northeasterly outflow. Based on the organization, the disturbance intensified into a tropical depression on February 13. Although there were gale-force winds in the southwest periphery, the circulation was located on the northern edge of the convection. The depression neared tropical storm intensity, but an increase in wind shear from a nearby trough prevented further intensification. The JTWC estimated peak 1-minute winds of 85 km/h (50 mph), making the system a tropical storm by their assessment. A building ridge to the south turned the depression to the northeast, bringing the system near Europa Island. A station on the island recorded sustained winds of with gusts to about three hours before and after the closest approach; the observations suggested that the depression could have become a tropical storm. Soon thereafter, the associated convection dissipated and the circulation turned westward. After crossing over its former path, the depression dissipated on February 17 very close to where it developed.