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
A long-lived system developed on February 28 in the Australian region south of February 28, and moved westward. On March 7, the JTWC initiated advisories on the system as Tropical Cyclone 26S, briefly estimating peak 1-minute winds of 65 km/h (40 mph) the next day. Soon after, the system weakened into a tropical depression, crossing into the south-west Indian Ocean late on March 8. At that time, it was designated Tropical Disturbance E2. Continuing westward along the northern edge of a strong ridge, the disturbance failed to intensify due to easterly wind shear. Although the MFR ceased issuing advisories, they noted that a distinct circulation persisted, reaching a location to the north of Mauritius by March 16. That day, it turned back to the east with a sporadic area of convection, influenced by the larger Tropical Depression E3. Two days later, the system organized enough for the MFR to reclassify it as a tropical disturbance. The system failed to reorganize much, and dissipated on March 20. Another tropical disturbance, named E3, formed on March 11 in the eastern portion of the basin. It initially failed to develop more, but after an increase in convection, the system intensified into a tropical depression on March 14 while moving generally west-northwestward. On the next day, the system began drifting to the southwest due to weak steering currents. On March 16, the JTWC initiated advisories on the system as Tropical Cyclone 28S, briefly upgrading it to tropical storm status on the next day. On March 18, the depression began weakening, dissipating three days later.