AWIO20 FMEE 101116
TROPICAL CYCLONE CENTER / RSMC LA REUNION / METEO-FRANCE

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

DATE: 2026/09/10 A 1200 UTC

PART 1: WARNING SUMMARY

NIL.

PART 2 : TROPICAL WEATHER DISCUSSION:

The basin is in a winter pattern, with weak to moderate near-equatorial convective activity in the trade wind deceleration zone.

The current large-scale low frequency background maintains a sinking anomaly over the tropical Indian ocean area, as well as a lack of convergence, thus yielding unfavorable conditions for cyclogenesis. A Kelvin wave as well as an equatorial Rossby wave are forecast to move across our basin in the coming days, but these should not have any significant consequences over the South-West Indian ocean : the vorticity increase driven by this wave activity should remain limited to the North Indian ocean tropics where the current seasonal background is a bit more conducive (hence a slight cyclogenesis signal from mid-September near India according to some models).

Development of a tropical storm is not expected during 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.