AWIO20 FMEE 291108
TROPICAL CYCLONE CENTER / RSMC LA REUNION / METEO-FRANCE

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

DATE: 2026/10/29 A 1200 UTC

PART 1: WARNING SUMMARY

NIL.

PART 2 : TROPICAL WEATHER DISCUSSION:

The basin shows a weakly marked near-equatorial trough (NET) near 5oS between 60o and 80oE. Convective activity is weak on the northern side of the NET and moderate on its southern side near the Chagos.

Equatorial easterly wind anomalies driven by El Nino and the positive phase of the Indian Ocean Dipole (IOD) maintain an unfavorable large-scale pattern for cyclogenesis over the eastern part of the basin. However, the MJO is currently present over the Maritime Continent, still producing a westerly wind anomaly over the northwest of the basin, enhancing more favorable conditions in the case of a low-level precursor arriving from the east.Actually, a Rossby wave currently over the eastern part of the basin is expected to progress westward and could generate or enhance this precursor at the end of the NET, near the Seychelles by mid-next week.



10-day outlook:
In the second half of next week, we will still monitoring the westward progression of the Equatorial-Rossby wave across the basin, which could intersect with a Kelvin wave and some actives MRG modes during this period and materialize the risk of cyclogenesis over the northwestern 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.