Tropical cyclone 21S (Imelda) remains active in the South Indian Ocean…located approximately 465 NM north-northeast of La Reunion (sustained winds of 45 knots, with gusts to near 55 knots)

PDC Global Hazards Atlas displaying 3 hour precipitation accumulation, tropical cyclone 21S (Imelda), with JTWC positions, segments and winds…over the South Indian Ocean

Tropical cyclone 21S (Imelda) remains active in the South Indian Ocean…located approximately 465 NM north-northeast of La Reunion island. This tropical cyclone has peaked in strength, or is peaking now. It has tracked south-southeast at near 6 knots, over the past six hours. Satellite imagery shows a shallow curved band of clouds wrapping into the low level circulation center.

The low level circulation is still well defined, with 40-45 knot winds within a fairly symmetrical radius. Despite the fact that most computer models have shown a significant re-development of 21S, environmental factors have recently become less favorable. As a result, the Joint Typhoon Warning Center (JTWC)

has changed its forecast philosophy. This new outlook calls for a gradual dissipation over the next 72 hours.

A trough of low pressure has moved over the circulation of TC Imelda, which is the primary cause…interrupting the continued strengthening. At the same time, the vertical wind shear is low to moderately strong, and sea surface temperatures are still favorable. However, these factors aren’t enough to overcome the negative effects of the low pressure trough over the system.

The current position of 21S is to the north-northeast of La Reunion island, and well to the east of Madagascar. This system has taken a rather abrupt turn to the south, after tracking westward for most of its life cycle. Some of the models are beginning to suggest that the low level circulation center could become completely disengaged from the upper level flow…causing the remnants of TC 21S to turn back to the west. Due to the large spread in tracks, the JTWC notes that there’s a low level of confidence in the current forecast direction.