Pundits disagree on La Nina impacts

Market analyst expects La Nina will cut Argentina’s corn crop, while weather expert downplays the system

A well-know weather expert disagrees with analysts who are reducing South America’s production prospects due to a looming La Nina event.

Reuters reports that one of its own analysts has decreased his estimate for Argentina’s potential corn harvest by more than eight million tonnes.

That is because forecasters at the United States National Oceanic and Atmospheric Administration predict that the La Nina climate phenomenon will develop in late autumn or early winter.

“Adverse weather conditions of heat and dryness are usually associated with La Nina in Argentina. So we currently expect relatively low corn yields,” Reuters’ senior analyst Hong Xu was quoted in a Reuters story.

He forecasts 28.4 million tonnes of production, down from the potential of 37 million tonnes if conditions were favourable.

But Drew Lerner, president of World Weather Inc., said analysts should not bank on big La Nina-related yield losses this time around.

Forecasters originally called for a La Nina this spring. But the Pacific Ocean equitorial temperatures did not cool as quickly as forecast.

By summer, the computer models had backed off to neutral El Nino Southern Oscillation (ENSO) conditions.

Now they are forecasting a weak La Nina materializing this fall or winter.

La Nina typically results in a drier bias for Argentina, Uruguay, southern Brazil and parts of Paraguay during the September through November period, when farmers are planting their summer crops.

That will not be the case this year due to the delayed onset of La Nina.

“We have missed the boat for most of that negative influence to occur,” said Lerner.

He noted that Argentina is in “really good shape” and conditions are turning the corner in southern Brazil, where Rio Grande do Sul just received a good rainfall and timely rain is in the forecast for Sao Paulo and Parana.

As South America shifts into its summer season in January and February, there is a tendency in La Nina years for central Brazil to receive above average rainfall while the drier bias will remain for southern Brazil and eastern Argentina.

“What’s going to be different this year versus past La Nina events is that those past La Nina events already had dryness early in that September through November period in southern Brazil and eastern Argentina,” said Lerner.

In addition, it is expected to be a weak La Nina, so he thinks it is premature to lower yield predictions.

“It’s probably not going to be enough to cause a significant amount of dryness problems,” he said.

Depending on how long La Nina lingers, it can bring dry conditions to the U.S. and portions of the Canadian Prairies.

Lerner said things could get interesting if it lasts beyond winter into spring and summer.

“The U.S. could get very dry in the western corn belt,” he said.

States such as Iowa, Minnesota and Wisconsin would suffer the most. That dryness could creep north into Manitoba and southeastern Saskatchewan.

It could also be parched in the southeast portion of the U.S. in the spring. That dryness would shift northwest as the summer unfolds.

“It’s already very dry right now in parts of the Delta and interior southeastern states,” said Lerner.

It is already dry in the hard red winter wheat producing region and is likely to stay that way during the La Nina winter.

While La Nina can cause dryness in North and South America, it typically delivers wet conditions to eastern Australia, Indonesia, Malaysia and India.

Lerner said by the time reporting agencies declare that La Nina has officially arrived its influence will be half over. He can already see signs of its influence around the world.

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