MFR began highlighting the potential for tropical cyclone development in their daily bulletins on 25 November, noting an increase in shower activity west of Seychelles.
Aided by the passage of a Kelvin wave and a favourable window in the Madden–Julian oscillation, a broad trough of low pressure began to take shape within the storm activity, extending across the equator.
Projections from computer models remained in disagreement over the system's future, complicated by the concurrent development of a tropical disturbance in the northwestern Indian Ocean along the same trough.
A loosely-defined wind circulation was detected 263 km (163 mi) south of Mahe, Seychelles on 29 November, offset from convection.
Over the following days, this circulation tightened within an environment moderately conducive for tropical development.
Météo-France declared the system as a zone of disturbed weather on 2 December; at the time the system had drifted west from its point of origin.
Although the storm was better organised and the environment conducive for intensification, the storm's wind field initially remained elongated and rainfall remained north of the storm's centre.
The disturbance became a tropical depression on 5 December, attended by an increase in rainbands and the return of convection at the centre of circulation; at 18:00 UTC that day, the system was upgraded to Moderate Tropical Storm Belna.

Belna was upgraded to severe tropical storm status early on 6 December.
Around the same time, a cloud-obscured eye briefly became apparent in microwave satellite imagery.
Due to a strengthening area of high pressure to its east, Belna began to curve from its initial westward drift to a more directed southwestward trajectory.
After a brief period of strengthening, Belna's central dense overcast remained largely unchanged throughout 6 December before signs of resumed intensification emerged by the day's end, followed by the development of another eye 9–19 km (5.6–11.8 mi) across.
With the storm's eye becoming better defined, MFR upgraded Belna to a tropical cyclone early on 7 December.
Hot towers were detected atop and within the storm's radius of maximum winds, suggesting the onset of a more accelerated rate of intensification.
However, the presence of dry air in the mid-levels of the troposphere towards the storm's southeastern quadrant prevented Belna from developing considerably.
At 18:00 UTC on 7 December, Belna's winds topped out at 155 km/h (100 mph) before fluctuating at a slightly lower strength over the ensuing day.
The system's structure disorganised significantly in a short period, caused by both the dry air and northerly wind shear.

The cyclone's structure varied considerably throughout 8 December, at times featuring a small eye surrounded by intense lightning activity and at other times degrading in response to an intrusion of dry air into the Belna's circulation.
Belna's strength was highly variable in part due to its small size, making it susceptible to changes in the local atmospheric environment and complicating forecasts.
On 9 December, a new phase of intensification began as Belna approached the Madagascar coast near Soalala, with an eye becoming apparent on visible satellite imagery.
In its advisories, the MFR noted a "spectacular intensification spell" in the hours leading up to Belna's landfall on Madagascar, assessing the cyclone's winds at 155 km/h (100 mph) and the pressure at 955 mbar (hPa; 28.35 inHg)–the lowest analysed over the course of the storm's existence—as Belna moved ashore at 15:30 UTC on 9 December.
The storm then began to weaken as it tracked farther inland, parallelling the western coast of Madagascar.
By 12:00 UTC the next day, Belna's winds had tapered below tropical depression thresholds, though the storm retained a well-defined wind circulation with tightly packed rainbands.
Belna curved towards the southeast over Madagascar, and deep convection associated with the cyclone dissipated on 11 December.
MFR issued their last update on the system later that day while the centre was over Haute Matsiatra,
MFR began highlighting the potential for tropical cyclone development in their daily bulletins on 25 November, noting an increase in shower activity west of Seychelles. Aided by the passage of a Kelvin wave and a favourable window in the Madden–Julian oscillation, a broad trough of low pressure began to take shape within the storm activity, extending across the equator. Projections from computer models remained in disagreement over the system's future, complicated by the concurrent development of a tropical disturbance in the northwestern Indian Ocean along the same trough. A loosely-defined wind circulation was detected 263 km (163 mi) south of Mahe, Seychelles on 29 November, offset from convection. Over the following days, this circulation tightened within an environment moderately conducive for tropical development. Météo-France declared the system as a zone of disturbed weather on 2 December; at the time the system had drifted west from its point of origin. Although the storm was better organised and the environment conducive for intensification, the storm's wind field initially remained elongated and rainfall remained north of the storm's centre. The disturbance became a tropical depression on 5 December, attended by an increase in rainbands and the return of convection at the centre of circulation; at 18:00 UTC that day, the system was upgraded to Moderate Tropical Storm Belna.
Belna was upgraded to severe tropical storm status early on 6 December. Around the same time, a cloud-obscured eye briefly became apparent in microwave satellite imagery. Due to a strengthening area of high pressure to its east, Belna began to curve from its initial westward drift to a more directed southwestward trajectory. After a brief period of strengthening, Belna's central dense overcast remained largely unchanged throughout 6 December before signs of resumed intensification emerged by the day's end, followed by the development of another eye 9–19 km (5.6–11.8 mi) across. With the storm's eye becoming better defined, MFR upgraded Belna to a tropical cyclone early on 7 December. Hot towers were detected atop and within the storm's radius of maximum winds, suggesting the onset of a more accelerated rate of intensification. However, the presence of dry air in the mid-levels of the troposphere towards the storm's southeastern quadrant prevented Belna from developing considerably. At 18:00 UTC on 7 December, Belna's winds topped out at 155 km/h (100 mph) before fluctuating at a slightly lower strength over the ensuing day. The system's structure disorganised significantly in a short period, caused by both the dry air and northerly wind shear.
The cyclone's structure varied considerably throughout 8 December, at times featuring a small eye surrounded by intense lightning activity and at other times degrading in response to an intrusion of dry air into the Belna's circulation. Belna's strength was highly variable in part due to its small size, making it susceptible to changes in the local atmospheric environment and complicating forecasts. On 9 December, a new phase of intensification began as Belna approached the Madagascar coast near Soalala, with an eye becoming apparent on visible satellite imagery. In its advisories, the MFR noted a "spectacular intensification spell" in the hours leading up to Belna's landfall on Madagascar, assessing the cyclone's winds at 155 km/h (100 mph) and the pressure at 955 mbar (hPa; 28.35 inHg)–the lowest analysed over the course of the storm's existence—as Belna moved ashore at 15:30 UTC on 9 December. The storm then began to weaken as it tracked farther inland, parallelling the western coast of Madagascar. By 12:00 UTC the next day, Belna's winds had tapered below tropical depression thresholds, though the storm retained a well-defined wind circulation with tightly packed rainbands. Belna curved towards the southeast over Madagascar, and deep convection associated with the cyclone dissipated on 11 December. MFR issued their last update on the system later that day while the centre was over Haute Matsiatra,
Cyclone Belna