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.
Timeline of the 2009–10 South-West Indian Ocean cyclone season
This timeline documents all of the events of the 2009-10 South-West Indian Ocean cyclone season which is the period that tropical cyclones formed in the Indian Ocean. Within the Indian Ocean most tropical cyclones form within the cyclone season which began on November 1 and will end on April 30. The scope of this article is limited to tropical cyclones that form in the Indian Ocean 30°E and 90°E to the south of the equator. When a zone of disturbed weather form or moves into the South-West Indian Ocean it is assigned a number and monitored by Météo-France who run the Regional Specialized Meteorological Center (RSMC) on Réunion Island. Should a tropical disturbance intensify and become a moderate tropical storm the two sub-regional tropical cyclone Advisory Centres in Maurtius and Madagascar in conjunction with RSMC La Réunion. The United States Joint Typhoon Warning Center (JTWC) also issue warnings on tropical cyclones in this region assigning a number with an "S" suffix. When monitoring a tropical cyclone the Joint Typhoon Warning Center will assess the cyclones intensity on the Saffir–Simpson Hurricane Scale whilst RSMC La Réunion, Maurtius and Madagascar use the Southwest Indian Ocean Tropical Cyclone Intensity Scale to assess a tropical cyclones intensity.