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;
South Atlantic tropical cyclone
During 2004, the large-scale conditions over the South Atlantic were more conducive than usual for subtropical or tropical systems, with 4 systems noted. The first possible tropical cyclone developed within a trough of low pressure, to the southeast of Salvador, Brazil on January 18. The system subsequently displayed a small central dense overcast (CDO) and was suspected to be at the peak of its development as either a tropical depression or a tropical storm during the next day. The system was subsequently affected by some strong shear, before it moved inland and weakened along the coast of Brazil before it was last noted during January 21. Within Brazil the system caused heavy rain and flooding with a state of emergency declared in Aracaju, after the river overflowed and burst its banks which flooded homes, destroyed crops and caused parts of the highway to collapse. However, it was noted that not all of the heavy rain and impacts were attributable to the system, as a large monsoon low covered much of Brazil at the time. The second system was a possible hybrid cyclone that developed near south-eastern Brazil between March 15–16. Hurricane Catarina was the third system, while the fourth system had a well-defined eye like structure, and formed off the coast of Brazil on March 15, 2004.
On February 22, 2006, a baroclinic cyclone intensified quickly and was estimated to have peaked with 1-minute sustained wind speeds of 65 mph (100 km/h), after radar data showed that the system had developed an eye and banding. However, there were questions about how tropical the system was, as it did not separate from the westerlies or the baroclinic zone it was in. Between March 11–17, 2006, a system with a warm core developed and moved southward along the South Atlantic Zone.