AWIO20 FMEE 251134
TROPICAL CYCLONE CENTER / RSMC LA REUNION / METEO-FRANCE

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

DATE: 2026/03/25 A 1200 UTC

PART 1: WARNING SUMMARY

NIL.

PART 2 : TROPICAL WEATHER DISCUSSION:

The basin pattern remains poorly defined and still lacks convergence, particularly in its western part due to prevailing easterly winds along the equator, west of 70oE. However, a weak Monsoon Trough (MT) structure has reformed over the eastern part of the basin, between 70 and 90oE and from 7 to 10oS, but with a weak monsoon flow and little convergence. Convective activity is moderate between northern Madagascar, the Comoros and the Tanzanian coast, as well as locally near the MT branch over the eastern part of the basin.

The strong easterly wind anomaly observed along the equator, which is unfavorable for cyclogenesis, is currently favored by various factors playing on different scales. First, the +SIOD and +IOD patterns, although they should slightly weaken in the coming weeks. It is also sustained by the MJO pattern, as the Indian Ocean is currently located ahead of the wet phase approaching from the west. At a smaller scale, this easterly anomaly is enhanced by an anticyclonic Rossby wave gyre.
However, from this weekend into next week, this wind anomaly should weaken as a Kelvin wave moves in from the west and a cyclonic Rossby wave approaches from the east of the basin.

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

10-day outlook:
Next week, the passage of a Rossby wave (currently associated with Tropical Cyclone Narelle), combined with a Kelvin wave and the approach of the wet phase of the MJO from the west, are expected to enhance the near-equatorial westerly flow and improve the MT pattern. Conditions are therefore expected to become more favorable for cyclogenesis in early April.

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.