Tropical Storm 11S 2025

Live tracking map, satellite images and forecasts of Tropical Storm 11S 2025 in the southwest Indian Ocean. Current wind speed 65km/h. Max 85km/h.

11S is located 1093 km south-southwest of Diego Garcia, and has tracked west-southwestward at 24 km/h (13 knots) over the past 6 hours. Maximum significant wave height is 5.2 meters (17 feet).

11S will move generally westward along the northwestern edge of the deep subtropical ridge for the next 12 to 18 hours.

A weakness in the ridging pattern to the south will result in weakening in the steering gradient, allowing the system to slow down a few knots through around 24 hours.

A new deep-layer subtropical ridge center moves eastward to a position southeast of the mascarenes after 24 hours, which will tighten up the gradient, allowing 11S to once again pick up speed.

The system is forecast to track just north of Mauritius around 72, then turn westward once again as it passes north of La Réunion in 4 days. In terms of intensity, the system will continue to struggle against the easterly shear and dry air, which are expected to persist for the next 36 to 48 hours.

Momentum conservation and brief bursts of convection are expected to lead to a steady 65 km/h intensity (35 knots) during this period, though there is about an equal chance that the system will weaken to less than 65 km/h (35 knots) during this timeframe.

Both the global and mesoscale models predict the shear to drop off significantly after 2 days, coincident with a slight increase in sea surface temperatures and a general moistening of the environment.

If the system can make it through the next 2 days, it is likely to reintensify as it passes the mascarenes and heads towards Madagascar, where it will find a much more favorable environment.

Deterministic model guidance shows a wide dispersion, with three distinct groupings of trackers. The GFS and NAVGEM comprise the northern group, with GFS taking the system near northern Madagascar before diving southward along the coast.

The middle group is the largest, with ECMWF, eceps, GALWEM, GEFS and the consensus mean. The third group consists of the UKMET and MOGREPS, taking the system sharply poleward after passing Mauritius, leading to a more than 1296 km cross-track spread by the end of the forecast.

Eceps and GEFS are in fairly good agreement in terms of the mean, with the modest member dispersion in both. The JTWC forecast has shifted northward significantly since the previous forecast and closely tracks the ECMWF tracker through the entire forecast.

Confidence over the next 3 days is medium, and low thereafter due to the extreme dispersion in the guidance. Intensity guidance shows a similar amount of uncertainty, with the SHIPS guidance steadily intensifying the system up to a peak of 140 km/h (75 knots) in the NAVGEM version.

The remainder of the guidance package shows either a flat intensity or a weakening through around 3 days, followed by intensification thereafter.

The JTWC forecast is roughly consistent with the consensus mean with low confidence.