Most, Not All, Brazil Soybean Areas Are Wetter
10/05/2025, 10:04 am EDT
Record Heat May Develop in Australia
10/08/2025, 5:59 am EDT
Climate Impact Company Week 2-to-4 South America Outlook
Issued: Tuesday October 7, 2025
Headline: Drier Northern Brazil/Wetter Southern Brazil.
Charts of the day: What to know about the current rainfall pattern.
Discussion: The ECM/ECM ENS continue a wet forecast bias across northwest South America, much of Brazil, and Uruguay during the past 30 days for all 15-day forecasts. This wet bias increases during the medium (6-10-day) and extended (11-15-day) range. The GFS/GFS ENS has a dry bias for West Brazil and Paraguay/Southeast Brazil. The current rainfall pattern is characterized by dryness in Brazil and much of Argentina according to NOAA’s 7-day observations. The 30-day percent of normal rainfall is somewhat drier than normal across Brazil with a wet signature in Northeast/East Argentina.
Week-2 Valid October 12-19, 2025: Central/East Brazil drier, Southeast Brazil wetter mid-October.
Discussion: To lower the rainfall bias, the ECM and GFS are equally combined to generate the week-2 forecast. Indicated is a wet anomaly across interior Southeast Brazil with dryness to the north. Paraguay is wet while Argentina is mostly dry. A strong frontal system delivers the rain with a trailing cooler air mass over Argentina. The CFS V2 is hot north of the front, the core of the heat is likely farther north in the drier zone. The primary change from the previous forecast (last Friday) is drier Central Brazil.
Week-3 Valid October 19-26, 2025: Favoring consistent ECM.
Discussion: ECM is consistent…hot East Brazil (biased by dry soil) and wet Southeast Brazil. Other forecast models vary widely. The potential concern is some AI models are building a hot/dry ridge across central South America but doubting that (forecast) solution based on poor climate signal support.
Week-4 Valid October 26-November 2, 2025: Marginally wet in Brazil; Very dry Northeast Brazil.
Discussion: Once again, forecast models vary widely. ECM ENS is conservative and consistent therefore favored to late October. Marginally wet weather is forecast across Central/interior Southeast Brazil.