According to the Brazilian Navy Hydrographic Center (BNHC), the tropical storm IBA formed in the southern Atlantic at 09:00 (local time) on 24 March 2019. It located at 36.0°W 18.5°S with maximum sustained wind speed of 18 m/s and a center pressure of 1008 hPa.
The imagery acquired by the polar-orbiting meteorological satellite FengYun-3D at 16:05 on 24 March (UTC) shows a structure of curved cloud band with high cirrus, convective cloud cluster around the storm is developing vigorously (Figure 1). More, on the northwest of the IBA, there is another spiral cloud with small scale, which also shows some similar feature of tropical cyclone. The distance between the centers of these two spiral cloud is about 500 km. Before the transition to the IBA, the predecessor, a tropical depression, formed within a monsoon as show in the imagery (Figure 2) acquired by the polar-orbiting meteorological satellite FengYun-3D at 16:25 on 23 March (UTC), while the small scale spiral cloud on the northwest of the IBA predecessor formed from the intensified convective cloud. Due to the dynamic interaction between these two cyclone systems, the development and path of the IBA would be complicated.
The IBA became the first South Atlantic tropical storm since the subtropical storm Arani in 2010. Although the BNHC has firstly named this cyclone as IBA from the Brazilian naming list, the other meteorological agencies did not name this cyclone yet. The monitoring of IBA would be continued in the future.
Figure 1. Tropical storm IBA as seen by the polar-orbiting meteorological satellite FengYun-3D at 16:05 on 24 March (UTC)
Figure 2. The imagery from the polar-orbiting meteorological satellite FengYun-3D at 16:25 on 23 March (UTC)