São Paulo Records Its Rainiest September Since 1943

Overview

• The Mirante de Santana station reported 253.8 mm of rain by Sept. 14, the highest September total in the Inmet series that begins in 1943.
• Sabesp's metropolitan system rose to about 52.1% capacity by Sept. 14 as stored volume climbed from roughly 837 million cubic meters to over 1 billion cubic meters.
• The Cantareira system's usable volume improved from about 33% at the end of August to 38.2% on Sept. 14 after 231.4 mm fell there in the first half of the month.
• Forecast models show an extratropical cyclone and advancing frontal systems around Sept. 18–20 that forecasters say could deliver additional heavy rain, strong winds and localized severe storms.
• Meteorologists point to Atlantic temperature contrasts, notably the South Atlantic Dipole, as the main driver of repeated frontal passages and warn that saturated soils keep the risk of flooding, landslides and persistent damp conditions high while full water‑supply recovery depends on more seasonal rain.