AWIO20 FMEE 171145
TROPICAL CYCLONE CENTER / RSMC LA REUNION / METEO-FRANCE

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

DATE: 2026/03/17 A 1200 UTC

PART 1: WARNING SUMMARY

NIL.

PART 2 : TROPICAL WEATHER DISCUSSION:

The basin features a weak Monsoon Trough (MT) east of 77oE, as well as a remnant MT branch further west, around 55oE, to the south of which lie the weakened remnants of system 12-20252026 located southeast of Mauritius. The convective activity associated with this system is moderate and poorly organized. There are also areas of weak convection near the two TM branches.

The current unfavorable ITCZ pattern is linked to a strong low-level easterly wind anomaly near the equator generated by the combined influence of the dry phase of the MJO over the eastern Indian Ocean and the maritime continent, the current low-frequency background (positive phases of the IOD and SIOD), and the passage of an anticyclonic Rossby wave gyre.

Former system 12-20252026 has no chances of reintensification because of wind shear and lack of low-level convergence. Elsewhere, conditions should remain unconducive for cyclogenesis in the coming days due to lack of convergence and vorticity within the ITCZ. Furthermore, the wave analysis remains unfavorable due to a strong easterly anomaly. Finally, none of the deterministic, ensemble, or AI models forecast the development of a tropical storm.

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

10-day outlook:
An approaching moist phase of the MJO from Africa during the last week of March, together with a Kelvin wave, could enhance convective activity over the western part of the basin, although vorticity is expected to remain insufficient due to other factors that remain less favorable (positive IOD/SIOD and unfavorable Rossby wave pattern).

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.