[29][30] On 1 March, Intense Tropical Cyclone Haleh formed out of an active phase of the Madden–Julian oscillation combined with equatorial waves,[31][32] generally moving south-southwestward and causing no impact towards land.

[39] Within the Intertropical Convergence Zone (ITCZ), an equatorial Rossby wave led to the formation of a weak cyclonic circulation near 7°S 75°E / 7°S 75°E / -7; 75 on 13 September, with intense convection, or thunderstorms, fluctuating in the system.

[40] East of the Chagos Archipelago, the system consolidated into a tropical disturbance on 14 September, retaining a well-defined centre, accommodated by sufficient ocean heat content.

[14] The storm then begin to track over a hostile environment of moderate wind shear, dry air entrainment in the mid-level troposphere, and cooler waters.

[47] Initially inhibited by dry air intrusion, the system intensified into a tropical depression, moving west-southwest along a ridge to the southeast, following strong bursts of convection over the centre.

[48] Convective cloud tops of −90 °C (−130 °F) signaled an improvement in the centre; as such, the system was upgraded to a moderate tropical storm, receiving the name Alcide from the Mauritius Meteorological Services (MMS).

[62] A weak low-pressure system developed in the equatorial Indian Ocean in Météo-France's area of responsibility on November 1 and moved slowly eastwards over the following few days while showing little signs of intensification.

[63] Late on November 9, as the developing precursor depression to Very Severe Cyclonic Storm Gaja in the Bay of Bengal moved further away and the competing low-level airflow convergence associated with it diminished, which was earlier associated with the westerly wind burst on either side of Indian Ocean.

[65] Very shortly afterwards, the system crossed the 90th meridian east and entered the Australian region, where it was classified by TCWC Jakarta as a tropical depression on November 10 local time.

[66] Later the same day, the JTWC assessed the developing low as having attained tropical storm status on the Saffir–Simpson hurricane wind scale, and assigned the system the unofficial designation 04S.

[67] A few hours later, at 10:00 UTC, the system moved back westwards and returned to the South-West Indian Ocean basin,[68] where it gained the name 'Bouchra' from Météo-France and underwent a twelve-hour phase of rapid intensification to severe tropical storm status.

[72] The period of residence in the Australian basin proved to be short-lived once again, however, with Météo-France indicating that Ex-Tropical Storm Bouchra had returned to the far eastern part of their area of responsibility early on November 13.

[77] The eye disappeared, as the cyclone, located 1,432 km (890 mi) southeast of Diego Garcia, tracked over an area of high wind shear and cooler waters.

[92] On 23 December, Cilida passed east of Mauritius, bringing beneficial rainfall and gusting winds that knocked down tree branches, blocking roads.

[24][25] During the middle of January 2019, strong convection caused by converging trade winds persisted over the western half of the basin, organising around a low along the coast of southern Mozambique.

[97] Northwest of Europa Island, Desmond situated in a marginal environment of high wind shear and dry air alleviated by strong outflow, with its centre obscured by cirrus clouds.

[100] Desmond induced heavy flooding upon Beira, Chinde, and Quelimane in Mozambique, displacing around 120,000 people across the provinces of Zambezia, Sofala, Manica, and Tete.

[101] A poorly-defined low northeast of Madagascar was detected by MFR on 19 January; the agency suggested that it would enter favorable conditions in the Mozambique Channel in the upcoming days.

[27] The storm's remnants formed a cold front that affected the weather in the Mascarene Islands and extended over the Mozambique Channel, bringing thunderstorms over the Comoros and Mayotte.

[114] Prior to the storm's arrival, a yellow alert was issued for the regions of Atsimo-Andrefana, Androy, and Anosy in Madagascar, in addition to a heavy rain watch for the districts of Maintirano, Antsalova, Belo Tsiribihina, Morondava, and Manja.

[120][29] Around 1,195 km (742 mi) east-northeast of Mauritius, the system consolidated within an environment of strong divergence aloft, low wind shear, and warm seas, with a broad circulation and northern deep rainbands over it.

[122] Convection then became much more concentrated under weak vertical wind shear, leading to the cyclone intensifying into a tropical storm on 5 February and receive the name Funani from the MMS.

[124] Under very warm waters of 30 °C (86 °F) and excellent radial outflow, Funani entered a period of rapid intensification,[125] presenting a sharp 22 km (14 mi) eye with tightening banding features.

[155] A pronounced eye emerged on satellite imagery around a robust ring of thunderstorms, with the storm aided by diminished wind shear and strong divergence aloft.

[172] The second landfall was far more severe, and overall, Idai killed 1,593 people and left thousands more missing, becoming one of the deadliest tropical cyclones in the modern history of Africa and the Southern Hemisphere as a whole.

[198] After the storm had passed, Mauritius Red Cross allocated hygiene kits, school supplies, and reconstruction materials for damaged homes, in cooperation with local emergency managers and government ministries of the county.

Soon afterward, Lorna encountered relatively strong vertical wind shear and steadily decreasing sea temperatures as it continued to track southwards, causing its gradual intensification trend to halt, and the JTWC to downgrade the system to a high-end tropical storm.

Due to the system being located on the very eastern edge of the South-West Indian Ocean basin during the previous two days, this slight easterly motion caused the cyclone to become centred directly over the 90th meridian east—the boundary of the Australian Bureau of Meteorology's area of responsibility.

Lorna strengthened to peak intensity while tracking southwards along the boundary between the two regions, attaining ten-minute sustained winds of 150 km/h (95 mph) by 18:00 UTC on April 28.

[214] Very strong vertical wind shear, analysed at 40 knots (74 km/h; 46 mph) at 09:00 UTC on April 29,[215] caused Lorna to become devoid of deep convection later that day.