AWIO20 FMEE 171135
TROPICAL CYCLONE CENTER / RSMC LA REUNION / METEO-FRANCE

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

DATE: 2026/02/17 A 1200 UTC

PART 1: WARNING SUMMARY



Bulletins WTIO24 044/10 and WTIO30 050/10 issued at 06 UTC sur la Forte Tempete Tropicale GEZANI. Next bulletins issued at 12 UTC.

PART 2 : TROPICAL WEATHER DISCUSSION:

The basin has a Monsoon Trough (MT) configuration east of 60E between 9 and 11S. Convective activity is moderate on the northern side of the MT, near a large circulation south of the Chagos Islands. Convective activity is also present near GEZANI, which is moving south of Madagascar.

The combination of an equatorial Rossby wave moving over the center of the basin and an active phase of the MJO is strengthening the monsoon flow and promoting low-level convergence within the TM. Conditions are therefore favorable for cyclogenesis over the center of the basin in the middle and end of the week.

Severe Tropical Storm GEZANI :
Information at 09 UTC : 
Estimated position :  29.7 S / 42.9E
Movement : SW, 19kt
Maximum wind speed (averaged over 10 minutes) : 55 kt
Estimated central pressure : 986 hPa
For further information, please refer to bulletins WTIO24 and WTIO30 issued at 06 UTC and following.

South of the Chagos archipelago :
The 0357Z ASCAT swath shows the presence of a large circulation within the TM around 11S/75E with winds reaching 25 kt in the monsoon flow. Convective activity was locally strong last night and this morning near the circulation but has weakened in recent hours.

The persistence of very good convergence on the equatorial side over the next few days should allow this circulation to develop into a moderate tropical storm by Friday, with good agreement among deterministic ensemble and AI models on this scenario. The minimum should initially move southward and then southwestward, steered by a subtropical ridge in the lower to middle troposphere located southeast of the minimum.

The risk of tropical storm formation over the center of the basin is expected to become moderate from Thursday 19th then high from Friday 20th February.





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.