Tropical Cyclone Imelda (21S) Restrengthens, Continues Towards Madagascar – April 14th, 201310.7S 53.4E
Tropical Cyclone Imelda (TC 21S), located approximately 315 nm northeast of La Reunion, has tracked west-southwestward at 03 knots over the past six hours.
Animated infrared satellite imagery shows a deepened central dense overcast feature over a well-defined low-level circulation center. This is also evident on an SSMI-S microwave pass. The initial position is based on closely grouped agency fixes and on the above microwave image with high confidence. The initial intensity is an average of subjective Dvorak estimates from PGTW, KNES, and FIMP.
Upper level analysis (ULA) indicates the system is between two ridge axes – one to the north and another to south in an area of low (05-10 knot) vertical wind shear (VWS). TC 21S has unpredictably tracked west-southwestward over the past 12 hours. From the same ULA, the steering ridge to the east was not significantly weakened by a passing mid-latitude trough as previously forecast. Instead, the ridge was deformed into a kidney-shaped anticyclone along a meridional axis. In response to this transformation to the steering ridge, 21S jogged westward. This recent development necessitated a slight change in the JTWC track forecast philosophy.