While the La Niña of 2011 was not friendly to Corn Belt agriculture, its dominance over South American agriculture has also been devastating. But as many Corn Belt farmers head into 2012 wondering about the potential weather, they know that soil moisture this spring is much less than it was a year ago. But what about the weather patterns domestically and globally that have been caused by La Niña?

Speaking to USDA’s annual Outlook Forum last week, meteorologist Brad Rippey of the World Agricultural Outlook Board reported the strong La Niña of last summer and fall has begun to fade into more neutral conditions. Using a series of probabilities, Rippey said the 95 percent probability of La Nina for January-March would decline to only a 22 percent probability in June-August and slowly rise to a 31 percent probability September-November. Consequently, there is only a 5 percent probability of an El Niño in April-June, but that will rise to a 32 pecent probability August-November. Rippey said a neutral condition is only 5 percent likely January-March, but that rises to 63 percent in May-July, then declines into November.

Rippey says the bottom line for the planting season of March through May is:

  • If La Niña rules the roost, expect a dry spring in the Southeast and Southwest. Cool conditions will likely be confined to the Northwest.
  • If the positive phase of the North Atlantic Oscillation overwhelms the La Niña signal, unexpectedly wet conditions may continue in the south-central U.S. Wetness could also affect the lower Great Lakes region, while dry conditions will plague the Southeast and much of the West. Warm conditions may shift farther north and west than expected.
  • And Rippey says the bottom line for the growing season of June through August is:
  • If La Niña remains a force, abundant rainfall across the South and East will contrast with hot, dry conditions from the Pacific Coast into the western Corn Belt.
  • If the positive phase of the North Atlantic Oscillation plays a big role, expect a warm summer across the nation’s northern tier and a rather cool summer from the southern Plains into the Southeast. The northern Plains and Midwest will need to be watched for potential drought development or intensification

La Niña is driven by cooler sea-surface temperatures in the Pacific equatorial waters, and they not only affect North American weather, but global weather. Watching that for the World Agricultural Outlook Board is meteorologist Eric Luebehusen who also reported to the attendees of the USDA’s Outlook Forum. His report covered not only European weather, but that in Eastern Europe, the Asian Sub-continent, and the agricultural areas of China.

As Europe heads into the spring, Luebehusen said, “The fall drought led to poor crop establishment in eastern Europe and Ukraine, but in contrast, above-normal rainfall benefited wheat in northern Africa and Russia. During the winter, conditions vastly improved over Ukraine and the Balkans, but a good spring will be vital for winter grains and oilseeds.”

While there is an area of drought in the region of Spain and Morocco, Luebehusen said, “The bigger concern in Europe will be the amount of winterkill in northern wheat and rapeseed areas, where the threshold for winterkill is ~ -18°C (0°F),” and his maps indicated widespread temperatures just below that level. He said, “Minimum temps (exist) in wheat areas, and lack of snow cover in key wheat and rapeseed areas of northeast Germany and northwest Poland increasing the risk for winterkill; also France’s durum wheat (threshold closer to -10°C (14°F).”

Luebehusen said the full impact of the sub-freezing temperatures and lack of snow cover will not be known until when the crops emerge this spring. He said the greater influence over European weather and crops is the North Atlantic Oscillation (NAO), which provided North America with totally different winters in 2011 and 2012. As the Jet Stream over the north Atlantic moves, he said the result is instantaneous on Europe:

  • Knowing how strong the relationship is going forward, a continuation of the current positive NAO would lead to spring warmth in the northern part of Europe.
  • Spring dryness would have a higher-than-normal likelihood of occurring in western parts of the Former Soviet Union/Mideast, with a dry bias in most growing areas,
  • Summer would feature more of the same temperature wise, although the contrast over Europe and the Middle East strengthens.
  • Summer dryness would become an increasing concern across the northern part of Europe if we maintain the current positive NAO cycle
  • In short, a continuation of a positive NAO would point to increasingly warm, dry conditions in northern Europe contrasting with cooler, wetter weather farther south and east,
  • Consequently, the NAO is forecast to remain in a positive phase into early March, which supports a warmer- and drier-than-normal weather to begin the spring from Europe into western portions of the Former Soviet Union (FSU)
  • Persistence would support an unfavorable forecast of warmth and dryness during the summer in Europe and western FSU, while favorable weather would persist in the Mediterranean region.

For China and eastern Asia, Luebehusen said the winter wheat crop benefitted from favorable fall moisture. But he said the rapeseed growing area in China was drier. In India, the monsoon benefitted both the wheat and rapeseed growing areas. For the spring, he said the La Niña influence on temperature in that part of the world is weaker, but cooler, and if La Niña weakens, there is less of a correlation with summer time temperatures. He said, “In short, La Niña supports a cooler- and drier-than-normal spring in northern India and much of China. If La Niña holds on into the summer, it would suggest cooler summer weather and some enhanced northern rainfall in Asia.” His conclusion for Eastern Asia for the season includes a lot of uncertainty because of the conflict between the La Niña influence and the International Research Institute (IRI) weather model

  • In Asia, the disparity between expert IRI outlooks and La Niña temperature correlation means – as one would expect – that other issues are weighing heavily into the equation.  Given the IRI high probability and the waning La Niña, it is hard to discount the warmer-than-normal weather forecast by IRI for the spring.
  • The spring precipitation correlation and IRI forecast line up better, leading to the expectation of wet weather in Indochina and southern India to contrast with drier conditions in the primary winter wheat and rapeseed areas.
  • A waning La Niña does not offer much confidence, but lingering summer impacts would include cooler conditions in the south with wetter weather in northern China

So the bottom line for China’s agricultural areas is the lack of any significant threats resulting from heat or dryness associated with a continuing La Niña. In fact, La Niña has more benefits to China’s agricultural areas than threats.

La Niña, which decimated 2011 US crops and 2012 South American crops, is becoming less influential over North American weather, and the spring and summer will bring more neutral growing conditions. However, the North Atlantic Oscillation, which provided a dry and mild winter, has the potential to provide a dry and warm growing season in the Corn Belt. The Global weather forces have combined to threaten winter crops in Europe and the Former Soviet Union, and their vitality will not be known for some weeks yet. Chinese crops should have escaped severe damage from the La Niña.

Source: FarmGate blog