Southern Cold Front May Spin Into Extratropical Cyclone as São Paulo Endures Heat Wave

Overview

• A strong frontal system is producing sustained heavy rain, storms, hail and gusty winds across Rio Grande do Sul, Santa Catarina and Paraná under orange and yellow alerts from Inmet.
• Forecasters say the front could deepen into an extratropical cyclone between Monday (Aug. 31) and Tuesday (Sept. 1), a development that would steer instability and cooler air toward the Southeast.
• If the cyclone forms as modeled, parts of the South could see short‑term totals above 100–120 mm, wind gusts over 90 km/h and increased risk of flooding, landslides and power outages in vulnerable areas.
• Meanwhile São Paulo and much of the Centre‑West are under a strong heat surge with daytime highs near 34–36°C and very low relative humidity in some interior spots, prompting a state heat alert.
• Agencies including Inmet, CHM and regional Defesa Civil are coordinating updates and local forecasts, and meteorologists say timing and intensity remain model‑dependent so residents should follow official alerts through early next week.