AWIO20 FMEE 061217
TROPICAL CYCLONE CENTER / RSMC LA REUNION / METEO-FRANCE

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

DATE: 2026/04/06 A 1200 UTC

PART 1: WARNING SUMMARY

NIL.

PART 2 : TROPICAL WEATHER DISCUSSION:

The ITCZ pattern over the central and eastern part of the basin has transitioned towards a Near-Equatorial Trough pattern (NET) east of 65oE and between 4 and 8oS, in relation with the strengthening equatorial westerly wind anomaly. Convective activity is moderate in convergence areas near the NET as well as further west between the north of Madagascar and the Comoros.
Ex-system INDUSA is still undergoing extratropical transition while gradually weakening as it moves away toward the mid-latitudes, near Amsterdam island.

The current NET pattern over the eastern part of the basin is being favored by the equatorial westerly wind anomaly in the wake of the moist MJO. But this conducive anomaly should gradually recede eastward as the dry phase of the MJO settles in over the Indian ocean by mid-April.
Moreover, the lack of equatorial convergence as well as anomalously dry air in the trade wind flow south of the NET should limit chances of cyclogenesis over the next few days.

Post-Tropical Depression INDUSA : 
Information at 10 UTC : 
Estimated position : 35.6 S / 75.0 E
Movement : South-east, 18 kt
Maximum wind speed (averaged over 10 minutes) : 30 kt
Estimated central pressure : 1008 hPa

INDUSA's remnants are expected to become fully extratropical by Monday night or Tuesday as they get embedded within a baroclinic mid-latitude trough while tracking southeastward. The low's structure is expected to be more and more elongated and convection-free as the warm core weakens and merges with a frontal system.

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



10-day outlook:
A new Rossby wave is expected to enter the eastern part of the Indian ocean around April 11-12, which should enhance vorticity at the eastern end of the NET, especially in the Australian area of responsibility, where a low-pressure system could end up forming. According to most NWP output, if a cyclogenesis occurs, it is more likely to remain east of 90oE, where conditions are more conducive. However, we cannot completely rule out the possibility of a tropical system entering the far east of our basin around mid-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.