AWIO20 FMEE 121151
TROPICAL CYCLONE CENTER / RSMC LA REUNION / METEO-FRANCE

BULLETIN FOR CYCLONIC ACTIVITY AND SIGNIFICANT TROPICAL WEATHER
IN THE SOUTHWEST INDIAN OCEAN

DATE: 2026/08/12 A 1200 UTC

PART 1: WARNING SUMMARY

NIL.

PART 2 : TROPICAL WEATHER DISCUSSION:

The basin displays a winter pattern, with generally weak convective activity confined to the northeastern part of the basin and near a broad and elongated low-pressure system east of the Seychelles near 5oS/62oE.

This weak low is primarily associated with an equatorial Rossby wave moving across our basin westwards, which remains unable to provide a conducive environment for cyclogenesis.

In the subtropics, south/south-east of Madagascar :A baroclinic low-pressure system could develop south of Madagascar by Friday 14th,  driven by the interaction between an upper-level trough and residual warm air from an undulating front in frontolysis. According to some deterministic models, the deepening of this low-pressure system could be accompanied by the isolation of a low-level warm seclusion by Saturday, the 15th, as it passes beneath the axis of an upper-level cut-off, over waters at 21/22oC. Despite a brief symmetrization of this low, models do not suggest a significant upward extension of its shallow warm core into the mid-troposphere because of an environment remaining too dry and sheared, thus limiting convective potential. The low is then expected to gradually fill by Sunday.

Development of a tropical or subtropical storm is not expected for the next 5 days.



10-day outlook:
Nothing to report

NOTA BENE: The likelihood is an estimate of the chance of genesis of a moderate tropical storm over the basin within the next five days:

Very low: less than 10%      Moderate: 30% to 60%      Very high: over 90%
Low: 10% to 30%              High: 60% to 90%

The Southwestern Indian ocean basin extends from the Equator to 40S and from the african coastlines to 90E.