The low that was to become Annette formed to the northeast of Cocos Island on 3 February and then moved southwest and slowly deepened. At about the same time, Willy was forming to the east and another was simultaneously developing within the Mauritius area and was to become tropical cyclone Haja .
After strengthening to cyclonic intensity on 5 February, Annette developed an erratic southwest track that was interrupted by a double loop. The loops occurred as a result of the passage of an upper trough south of Annette 's position. Further erratic movement was evident from 13 to 15 February before the cyclone moved into the Mauritius region on 16 February where further intensification took place. Annette reached severe cyclone status with a central pressure estimated at 960 hPa around 1200 UTC 8 February and maintained this status for the remainder of its life in the Western Region. During most of the period from 1200 15 February to 1200 UTC 19 February there was a clearly-defined eye. The eye was still visible at 1200 UTC 19 February when Annette was centred near 21°S, 70°E and close to the horizon of GMS-1.
Winds of 74 km/h were reported by a ship 40 km to the south of the centre at 1200 UTC 8 February. Another ship reported a wind of 93 km/h at 0000 UTC 8 February, however this report was from a posi- tion well to the south of the cyclone position in an area where the gradient was intensified by the interaction with a southern ridge.