Four of the storms attained tropical cyclone status, which is the equivalent of a minimal hurricane with 10 minute sustained winds of at least 120 km/h (75 mph).
[nb 1] The seasonal activity was evenly dispersed, officially beginning on December 9 when the Météo-France office (MFR) on Réunion started tracking Tropical Storm Ariny.
The strongest cyclone of the season was Gasitao, which formed at the same time as Hely and attained peak winds of 150 km/h (93 mph).
During the season, the Météo-France office (MFR) on Réunion island issued warnings in tropical cyclones within the basin.
Using satellite imagery from National Oceanic and Atmospheric Administration, the agency estimated intensity through the Dvorak technique, and warned on tropical cyclones in the region from the coast of Africa to 90° E, south of the equator.
Early on November 25, the storm moved ashore near Quirimbas National Park in the northeastern portion of Mozambique, and it dissipated a day later.
[6] For several days, the JTWC tracked a southwest moving area of disturbed weather in the Australian basin until it crossed 90° E on December 9,[7] located within the Intertropical Convergence Zone (ITCZ).
Based on the organization, the Mauritius Meteorological Services named it Ariny,[8] and the storm soon after attained peak winds of 115 km/h (71 mph),[7] just shy of tropical cyclone status.
[13] Later that day, the storm struck eastern Madagascar near Île Sainte-Marie, and it quickly weakened over land,[14] so much so that the JTWC discontinued advisories.
[14] The JTWC again issued advisories on January 28,[2] around which time Doaza passed just southeast of Juan de Nova Island.
On the next day, the storm attained tropical cyclone status, reaching winds of 135 km/h (84 mph) just west of Europa Island.
On January 30, the JTWC estimated peak 1 minute winds of 215 km/h (134 mph), by which time the storm was moving due southward.
[14] While crossing Madagascar, Doaza dropped a maximum of 113.9 mm (4.48 in) of rainfall over 24 hours, as well as producing a peak wind gust of 60 km/h (37 mph).
[15] The storm brushed the east coast of Mozambique, producing flooding rains in Sofala, Zambezia, and Cabo Delgado provinces.
[18] A circulation appeared within the ITCZ on February 23 just northeast of the northern tip of Madagascar, designated as a tropical disturbance that day.
[2] The storm stalled on February 29 due to a weakened ridge, and on that day Filao attained tropical cyclone status while reaching peak winds of 135 km/h (84 mph).
Late on March 1, Filao made landfall just southwest of Quelimane, Mozambique at peak intensity, and it dissipated the next day.
[20][21] Moving over Madagascar as a weak system, Filao caused little effects, although once in the Mozambique Channel, it produced wind gusts of 87 km/h (54 mph) along Juan de Nova island.
On March 15, it developed into a tropical storm about 700 km (430 mi) to the south-southeast of Diego Garcia while moving on a west-southwest trajectory.
On March 19, the JTWC estimated peak 1 minute winds of 240 km/h (150 mph) while the storm was passing 350 km (220 mi) northeast of Rodrigues.
[23] Simultaneous to Gasitao developing, another low pressure area was forming to the north-northeast of Tromelin,[26] classified as a tropical disturbance on March 16.
[26] Soon after, Hely intensified to tropical storm status, reaching peak winds of 95 km/h (59 mph) early on March 18 about 200 km (120 mi) northeast of the northern tip of Madagascar.
The storm diminished in intensity, dropping to tropical depression status on March 20;[26][27] on that day, the JTWC discontinued advisories.
[2] The MFR continued tracking the circulation, and Hely turned back to the west on March 24 due to a strengthened ridge following Gasitao's dissipation.
Moving toward Madagascar, Hely passed north of Tromelin and again became a tropical storm on March 27,[26][27] the same day that the JTWC reissued advisories.
[26][27] After a period of inactivity lasting a month, the final storm of the season began forming on May 4 between Agalega and Diego Garcia.