莫桑比克海峡95S - 17.0S 41.4E

红豆棒冰冰

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95S INVEST 260311 1200 17.0S 41.4E SHEM 15 0

Ragasa

AWIO20 FMEE 111128
TROPICAL CYCLONE CENTER / RSMC LA REUNION / METEO-FRANCE

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

DATE: 2026/03/11 A 1200 UTC

PART 1: WARNING SUMMARY

NIL.

PART 2 : TROPICAL WEATHER DISCUSSION:

The basin is in a monsoon trough (MT) configuration east of 50E. Convective activity is moderate on both sides of the MT and in the Mozambique Channel.

The dry phase of the MJO is expected to gradually move away towards the east of the basin and the maritime continent by mid-March, enabling the return of more conducive conditions for convective activity over the western part of the basin. In the next few days the passage of a low-amplitude Kelvin wave could contribute to the strengthening the monsoon flow. In addition, a Rossby wave is expected to gradually enhance the monsoon flow and vorticity within the MT over the center and west of the basin between the end of the week and the beginning of next week.

Near Agalega :
The strengthening of the monsoon flow and the arrival of a new subtropical ridge south of Madagascar should gradually enhance convergence on both sides of the MT over the western part of the basin, especially near Farquhar or Agalega. Moreover, this area could benefit from good upper divergence on the northwestern edge of an upper trough located over the east of the Mascarenes. These favorable conditions should enable the formation of a low-pressure area from Thursday 12th near Agalega. The deterministic GFS model suggests a tropical storm development from Friday 13th or over the weekend. On the other hand, the deterministic IFS model injects a little more dry air into the western edge of the system due to a larger trough, meaning that the system fails to reach tropical storm status. A significant number of ensemble and AI models also forecast significant cyclogenesis potential by Saturday.

The risk of tropical storm development near Agalega is low from Friday 13th then becomes moderate from Saturday, March 14th.

Off the south/south-west of the Chagos archipelago :
Due to a lack of convergence in the lower layers, cyclogenesis is no longer considered for this suspect area.

For the next 5 days, there is no potential for this suspect area to develop into a moderate tropical storm.

In the Mozambique Channel :
A weak northerly monsoon flow is expected to settle along the African coast from Wednesday 11th, becoming moderate on Thursday 12th, feeding a weak low-pressure area currently located near the northeast coast of Mozambique (near the province of Nampula). At the same time, a surge of trade winds is underway over the southern Mozambique Channel. According to most models, the convergence between these flows does not seem optimal at the moment, occurring a little too close to the coast of Mozambique or even slightly inland, which reduces the potential for cyclogenesis. Nevertheless, some models suggest that the convergence will remain a little further out to sea. In this case, with a favorable large-scale context (low shear, good upper divergence, warm surface waters), cyclogenesis is possible, as suggested in particular by several successive runs of the GEFS ensemble. Chances of cyclogenesis will therefore depend mainly on how efficient the low-level convergence is and on the proximity of the low-pressure area to land.

The risk of tropical storm formation in the Mozambique Channel, near the coast of Mozambique, is expected to become very low from Friday 13th, then low on Saturday 14th.

Over the far east of the basin :
Due to a lack of convergence in the lower layers and an increase in deep shear, cyclogenesis is no longer considered for this suspect area.

For the next 5 days, there is no potential for this suspect area to develop into a moderate tropical storm.



10-day outlook:
During the following week (March 16th to 22nd), the risk of cyclogenesis regarding the suspect area in the Mozambique Channel could increase.

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.