La Nina Weakening, Its Future Unclear

February 7, 2012

Key indicators in the Pacific Ocean indicate weakening of the La Nina over the past month, as sea temperatures have warmed up in the eastern equatorial Pacific Ocean. 

It is hard to know whether this is the “beginning of the end”  of the  La Nina ,  or just a temporary fluctuation.   It is not the first time La Nina has weakened.   Steady warming of the equatorial seas also occurred in October and November.  This was followed by renewed La Nina strengthening (cooling) in December and early January. 

 

 

Argentina Crops Affected by La Nina Drought

The behavior of La Nina has huge implications for crop production in Argentina, where it causes drought.  The recent heavy rainfall in Argentina may be linked to the weakening of  La Nina.  See increased showers in Argentina corn and soybeans below:

 

La Nina Crop Season Review 2010-11

A very strong La Nina occurred last year causing a period of extreme heat and moisture stress in Argentina crops.   The severe drought occurred from the spring to mid summer.   Break-through rains developed  mid January, continuing on and off through early March 2011.   

Corn and soybean production last season would have been worse had heavy rainfall not developed the final 6 weeks of the growing season.  See how last year the growing season ended on a wet note:

 

Argentina corn production was bolstered by a record high planted area in 2010-11,  up 30% from the previous year.  Corn production was still sizeable despite drought damage , 22.5 million metric tons and just 4-5% less than the previous growing season.   

Note that extremely large  corn plantings are projected again in the current crop season, far right on the chart below: 

 

 

Soybeans finished at 49 million metric tons last season, an “average” harvest, when measured against production in the mid 2000s.   It was 10% below the record harvest gathered the previous year,  54.50 MMT.

For more on Argentina crop potential with La Nina read yesterday’s report:  http://www.martellcropprojections.com/CropProductionReports/Argentina-Corn-Sharply-Lower-on-Drought-Soybeans-Still-Responding-to-Rain

 

 

 

Steady Weakening Predicted 

For its part the Climate Prediction Center anticipates steady weakening of the La Nina into the Southern Hemisphere fall  March-May.

If La Nina re-strengthens, renewing drought, Argentina crop prospects would worsen.   The 2008-09 growing season is the best analog for  ongoing drought and worsening yields in  Argentina corn and soybeans.

  

 

The GFS model predicts more heavy rain today in the central Argentina grain belt.  See where corn and soybeans are grown:

 

Clearing and cooler weather will develop Thursday and Friday, as showers spread northward into Brazil: