Overview

• São Paulo’s state civil defense warns that thunderstorms with strong gusts and isolated hail may develop Sunday night into Monday, following a hot morning with critically low humidity near 12% in parts of the interior.
• Santa Catarina faces orange-level alerts for heavy rain that may reach about 100 mm in a day, with wind gusts of 60–100 km/h and risk of hail, flooding, fallen trees and power outages.
• Timing in SC points to storms beginning early Sunday in the Grande Oeste and Sul, spreading to Greater Florianópolis, Vale do Itajaí and the Norte during the afternoon, with gradual improvement on Monday as the front moves away.
• Models referenced by local bulletins indicate the system should intensify with cyclone and polar air influence, bringing a marked cool-down from Tuesday and occasional gusts that could exceed roughly 70 km/h in parts of São Paulo.
• Authorities note that the incoming moisture should raise humidity and temporarily lower wildfire risk in São Paulo, with Inmet’s Alert-AS system maintaining graded weather warnings nationwide.