Back
September 28, 2017

Spring Weather Forecast from Brazilian National Weather Service

Author: Michael Cordonnier/Soybean & Corn Advisor, Inc.

As our focus shifts to the South American growing season, I thought it would be interesting to take a look at the "spring" forecast issued last week by the Brazilian National Meteorological Institute (Inmet). Their spring forecast is for the months of October-November-December. Calling it a "spring" forecast is sort of a misnomer because by the end of December some of the earliest planted soybeans will be approaching maturity, but that is the way Inmet classifies the seasons.

Many farmers in Brazil are already concerned about the potentially slow start to the summer rainy season, so there is a heightened interest in the forecast for the next three months. Additionally, a mild La Nina seems to be forming and it generally results in below normal rainfall for east-central and southeastern Brazil during the three month period.

While most of Brazil has been dry up until this point, there are improved chances of scattered showers this week in Brazil, but most forecasters are not predicting good consistent rains until the second half of October. If that turns out to be the case, the early plating progress in Brazil may be somewhat sporadic.

Below is Inmet's forecast by regions in Brazil for the months of October-November-December. In the summary at the end I have indicated the approximate percentages of the 2017/18 Brazilian soybean and full-season corn acreage that may be impacted by potentially adverse weather over the three month period.

Center West Brazil - The rainfall in most of Mato Grosso and Mato Grosso do Sul is forecasted to be above normal during the three month period. Rainfall is expected to be below normal in far eastern Mato Grosso and into Goias. The temperatures for the region are expected to normal. This would generally benefit the soybean crop in Mato Grosso, which is Brazil's largest soybean producing state with approximately 27% of Brazil's soybean production and Mato Grosso do Sul (approximately 7% of the total). It would not be good news for Goias (approximately 9% of the total) and eastern Mato Grosso (approximately 5% of the total).

Southern Brazil - In the states of Parana, Santa Catarina, and Rio Grande do Sul, the rainfall over the three month period is expected to be normal or slightly above normal with normal temperatures. This would benefit the soybean production in Parana (approximately 17% of Brazil's total), Santa Catarina (approximately 2% of the total) and Rio Grande do Sul (approximately 16% of the total).

Southeastern Brazil - In the states of Minas Gerais and Sao Paulo, they are forecasting a slow start to the rainy season with below normal rainfall and hotter than normal temperatures during the three month period. This may be bad news for the soybean production in Minas Gerais (approximately 4% of the total) and Sao Paulo (approximately 3% of the total).

Northeastern Brazil - The forecast for the next three months is for below normal rainfall and hotter than normal temperatures in western Bahia, southern Maranhao, and southern Piaui. This is definitely bad news for the soybean crop in Bahia (approximately 4% of the total), Maranhao (approximately 2% of the total) and Piaui (approximately 2% of the total).

Summary

  • The summer rainy season may start slower than normal with a lot of regional variability.
  • The rainfall and temperatures during October-November-December is forecasted to be dryer than normal and hotter than normal from central Brazil into eastern, northeastern, and southeastern Brazil. In other words, the further east you go the greater the possibility of adverse weather.
  • In a very broad sense, approximately 66% of Brazil's soybean production is forecasted to have normal weather during the three month period. Approximately 33% of Brazil's 2017/18 soybean production could be in the region that is forecasted to be hotter and dryer than normal during the three month period. The early planted and early maturity soybeans could be impacted the most by the potentially adverse weather.
  • The states forecasted to have good "spring" weather include: most of Mato Grosso, Mato Grosso do Sul, Parana, Santa Catarina, and Rio Grande do Sul.
  • The states forecasted to have less than ideal "spring" weather include: eastern Mato Grosso, Goias, Sao Paulo, Minas Gerais, Tocantins, Bahia, Maranhao, and Piaui.
  • Approximately 40% of Brazil's full-season corn production could be in the region forecasted to be hotter and dryer than normal. Full-season corn production will represent approximately 30% of Brazil's total corn production in 2017/18.
  • Inmet did not make any forecast for the weather during the safrinha corn growing season.
  • The forecast can change of course, so I would view these forecasts as a cautionary tale as we start the Brazilian 2017/18 growing season.