Subtropical Cyclone Anita's Potential to Tropical Transition Under Warmer Sea Surface Temperature Scenarios

On 6 March 2010, Anita, the first subtropical cyclone observed over the South Atlantic Ocean, formed near the southeastern coast of Brazil, and during its life cycle, Anita almost acquired a tropical structure. The potential of Anita to undergo tropical transition in scenarios of increased sea surface temperature (SST) was investigated through a set of numerical sensitivity experiments. The results show that, if the SST had been 2°C warmer throughout Anita's life cycle, the system would have undergone tropical transition in its maturity stage; however, if the SST had increased only during Anita's quasi‐stationary period, the tropical transition completion would have occurred only with higher values of SST (6°C). Key Points The 2‐day quasi‐stationarity of subtropical cyclone Anita near the southern coast of Brazil is likely to have prevented its tropical transition This study shows that Anita could have undergone tropical transition if the sea‐air turbulent heat fluxes had increased