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.
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.