A new extratropical cyclone is forming between Rio Grande do Sul and Santa Catarina, bringing a risk of intense rainfall and strong winds [1].
The system threatens the southern region of Brazil with severe atmospheric instability. This weather pattern can lead to significant flooding and infrastructure damage in coastal and inland areas.
Pedro Côrtes, a climate and environment analyst for CNN Brasil, said a new extratropical cyclone is forming between Rio Grande do Sul and Santa Catarina and should intensify rains in the region [1]. The system developed as a new cold front interacted with an area of low pressure over the South Atlantic [1], [2].
Meteorologists warn that the storm could produce severe conditions. The CNN Brasil meteorology team said the system may generate winds of up to 100 km/h [3] and precipitation ranging from 150 to 200 mm in certain points of the southern states [1].
Reports on the timing of the cyclone's formation vary across sources. CNN Brasil reported the formation occurred on Monday, Aug. 31 [1]. Other reports indicated the system began forming as early as Aug. 20 [3] or would not form until Sept. 14 [4].
The cyclone is currently positioned over the Atlantic Ocean, east of the coast of Rio Grande do Sul [1], [2], [3]. Local authorities typically monitor these systems closely due to the potential for rapid intensification and the resulting impact on transport, and safety in the southern states.
“The system may generate winds of up to 100 km/h and precipitation of 150 to 200 mm.”
The formation of extratropical cyclones is a recurring challenge for southern Brazil, where the convergence of cold fronts and Atlantic low-pressure systems often triggers extreme weather. The predicted rainfall of up to 200 mm [1] exceeds typical thresholds for flash flooding, potentially disrupting agriculture, and urban logistics in Rio Grande do Sul and Santa Catarina.
