The Australian government has now joined the United States in declaring a La Nina event.
The U.S. Climate Prediction Center was the first to declare a La Nina event two months ago. The Australians came out today saying that La Nina has become established in the tropical pacific. They suggest it will be weak and short-lived, only persisting through the Northern Hemisphere spring.
Our calculation of the sea surface temperature departure in the equatorial eastern pacific has been consistently running between minus 0.7 to minus 0.8 degrees Celsius for the past three months (September to November). This suggests a weak La Nina.
The greatest potential impact this La Nina will have during the next few months agriculturally will be in South America. We have begun to notice a trend towards drier weather in central Argentina during the past few weeks. There tends to be a strong correlation between La Nina and dryness in central Argentina sometimes extending into southern Brazil.
Due to the lack of any persistent hot weather and adequate subsoil moisture, we don't think any significant stress to corn and soybeans has occurred yet. However, going forward this will be the area to watch for potential crop problems.
The major soybean areas of central Brazil have settled into their normal rainy season pattern. There was some concern earlier that late planting of the soybean crop might affect double-crop corn acreage. However, that appears less likely now as producers made rapid progress planting the crop once the rains came and the La Nina event may extend the rainy season further into the fall, which would be very favorable for double-cropped corn.
Michael Palmerino can be reached at firstname.lastname@example.org
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