Compare ECM and AI WXNEXT V3 10-day Rainfall Forecast for Brazil

Climate Impact Company Week 2-4 Outlook

South America

Issued: Thursday October 1, 2026

Highlight: Maintaining wet pattern East/Southeast Brazil; Argentina is cool.

Charts of the day: Compare ECM and AI WXNEXT V3 10-day rainfall forecast.

Discussion: Wet forecasts for Southern Brazil are indicated for several days wettest by ECM while the AI WXNEXT V3 (Google Deep Mind) is not as wet. The rainfall trend is mixed, wetter across Northern Argentina during the past 7 days while Paraguay is dry. A compromise between the two forecast solutions still supporting widespread significant rain for Southern Brazil.

Week-2 Ahead (October 11-18, 2026): Stays wet East/Southeast Brazil.

Discussion: The elongated upper trough through central South America maintains a wet Chile and East/Southeast Brazil forecast with cool temperatures in Argentina.

Week-3 Ahead (October 18-25, 2026): More Southern Brazil and Chile rains.

Discussion: As previously indicated, the upper trough is a little weaker and shifts slightly south. Cool weather is maintained Western Argentine, with wet conditions in Chile and East/Southeast Brazil (also) continuing.

Week-4 Ahead (October 25-November 1, 2026): Hotter north of the Southeast Brazil rains.

Discussion: Once again, the upper trough edges slightly southward to Central Argentina. Wet weather becomes confined in Brazil to the southeast section while anomalous heat (in Brazil) broadens.