In late March 2019 a rare tropical storm formed in the South Atlantic basin, off the coast of Brazil.
By Jochen Kerkmann and Jose Prieto (EUMETSAT), Sancha Lancaster (Pactum), Humberto Alves Barbosa (LAPIS)
On 24 March, a tropical storm, named Iba, formed off Brazil's southeastern coast, where such cyclones are a rarity. This was only the fourth tropical cyclone known to have formed in the Southern Atlantic Ocean and the first since 2010. Only one tropical cyclone of hurricane intensity is known to have formed in this area — Catarina, which in March 2004 reached 139 km/h before making landfall in southern Brazil (see case study).
Figure 2 is the Meteosat-10 Tropical Airmass RGB animation showing the Iba's development from 24 March 11:00 UTC to 25 March at 10:00 UTC.
Figure 2: Met-10 Tropical Airmass RGB animation, 24 March, 11:00 UTC–25 March, 10:00 UTC (hourly images)
On 25 March the storm reached maximum gusts of 87 km/h, but did not reach hurricane strength. Figure 3 shows that the shear at 09:00 UTC was relatively high, so further development was not very likely.
The animation of the GOES-16 infrared imagery (Figure 4) confirms that the storm did, indeed, start to dissipate.
Figure 4: GOES-16 infrared animation, 25 March 16:00–20:45 UTC
By 26 March it had reduced to a tropical depression over the ocean, where it still generated some showers and thunderstorms southeast of the northern region of Brazil, with moderate winds.
Tropical Storm Iba off the coast of Brazil (CIMSS Blog)
Tropical anomaly Storm Iba swirls off Brazilian coast (The Weather Network)
Catarina - 2004 (NOAA SPSD)