AWIO20 FMEE 181232
TROPICAL CYCLONE CENTER / RSMC LA REUNION / METEO-FRANCE

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

DATE: 2026/04/18 A 1200 UTC

PART 1: WARNING SUMMARY

NIL.

PART 2 : TROPICAL WEATHER DISCUSSION:

The basin keeps a poorly-defined configuration, with a weakening near-equatorial trough (NET) between 65 and 80E associated with very weak equatorial westerlies. Convective activity is weak to moderate in the trade wind slowing area and at the southeastern tip of the NET near a broad low-pressure area located around 11S/84E.

This weak low-pressure area over the eastern part of the basin is associated with a Rossby wave moving westward along the 10S parallel, which is expected to remain too weak to trigger cyclogenesis due to unfavorable large-scale conditions. Indeed, an easterly wind anomaly is expected to persist near the equator over the next few days ahead of a new moist phase of the MJO approaching from Africa. This should maintain a poorly-defined NET with weak convergence on its equatorial side until next weekend (25-26 April).

Development of a tropical storm is not expected over the next 5 days.

10-day outlook:
From the last days of April, the incoming moist phase of the MJO over the western Indian Ocean, as well as a Kelvin wave, are expected to favor the return of a more favorable configuration with strengthening westerlies near the equator and a more convergent NET pattern. A slight risk of cyclogenesis could thus begin to emerge from D+10 onwards, especially over the central part of the basin.

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.