1999–2000 South-West Indian Ocean cyclone season
The 1999–2000 South-West Indian Ocean tropical cyclone season was the first on record in which two storms – Leon–Eline and Hudah – struck Mozambique at tropical cyclone intensity, or with maximum sustained winds of at least 120 km/h (75 mph). The most notable storm of the season was Eline, which was the longest-lasting storm on record in the basin. It lasted for 29 days while traversing the southern Indian Ocean, making the strongest landfall in decades along eastern Madagascar in late February. The storm was the first in a series of three storms that struck the country in early 2000, along with Gloria in March and Hudah in April. Collectively, the three storms killed at least 316 people. The season started on November 1, 1999, and ended for most of the basin on April 30, 2000; for Mauritius and the Seychelles, the season continued until May 15. These dates conventionally delimit the period of each year when most tropical cyclones form in the basin;
1999–2000 South-West Indian Ocean cyclone season
On December 23, a circulation with accompanying convection became evident about 400 km (250 mi) southeast of Diego Garcia, becoming a tropical disturbance. While moving to the south, the thunderstorms organized more, aided by low wind shear, good outflow, warm waters, and its position beneath an anticyclone. Curving west-southwestward due to a ridge to the south, the system intensified into a tropical depression and later Tropical Storm Astride on December 25. That day, the JTWC classified the system as Tropical Cyclone 03S. The storm developed a large area of convection, prompting the MFR to upgrade it to a severe tropical storm on December 26, estimating 10‑minute winds of 95 km/h (60 mph). On December 27, the JTWC upgraded Astride to the equivalent of a minimal hurricane due to the appearance of an eye feature, estimating 1‑minute winds of 120 km/h (75 mph). Later that day, the storm weakened unexpectedly, perhaps related to wind shear from a trough to the south. The convection deteriorated markedly, and the weakening storm turned more to the west-northwest on December 29 due to a weaker ridge. Convection reorganized slightly, although it was dislocated from the center. Early on December 30, the storm passed about 70 km (45 mi) northeast of Tromelin Island. Curving back to the west, Astride struck northeastern Madagascar between Vohemar and Antsiranana on December 31 as a minimal tropical storm. It emerged into the Mozambique Channel as a tropical depression, and despite forecasts to the contrary, it reintensified into a tropical storm before passing near Mayotte on January 2. Early the next day, Astride weakened back to tropical depression status before moving ashore eastern Mozambique near Pemba, dissipating soon after.