In February Klaus Wolter came to the conclusion that there was an even chance that La Niña conditions could extend into 2012. He wrote then:
While La Niña conditions are guaranteed well into 2011, it remains to be seen whether it can rally once more to cross the -2 sigma barrier, and/or whether it will indeed last into 2012, as discussed six months ago on this page. I believe the odds for a two-year event remain well above 50%, made even more likely by the continued unabated strength in various ENSO indices.
Bob Tisdale points out at WUWT that
NINO3.4 SST anomalies (a commonly used El Niño-Southern Oscillation Index) have dropped significantly below the -0.5 deg C threshold of a La Niña Event. They are presently at approximately -0.74 deg C.
NINO3.4 SST anomalies
NOAA has yet to update its El Niño / La Niña forecasts but has called a “La Niña watch” but Bob Tisdale is ahead of them in calling the return of La Niña which is not too far away from Wolter’s forecast.
Update!! 8th September: NOAA now calls it: La Niña is back
But Agriculture.com reports that the money is already betting on La Niña conditions for this winter and into 2012:
Sentiment towards commodities lying in the traditional path of conditions known as La Nina is starting to turn more bullish, exacerbated by supply shortages in a number of products like iron ore and coal.
Forecasting models by the U.S. National Weather Service’s Climate Prediction Center predict La Nina will redevelop this autumn. “Atmospheric patterns continue to reflect La Nina-like conditions,” the weather body said.
La Nina is a periodic climatic phenomenon that brings more rain to the western Pacific, and to a lesser extent, to the eastern Pacific. Climatologists blamed La Nina for last year’s floods that gripped Australia, resulting in major losses to coal and iron ore stockpiles.
But while it isn’t clear what impact La Nina might have on the production and shipment of commodities, its return isn’t expected to cause the same serious problems as in 2010. That’s because historically the La Nina weather phenomenon occurs in bursts of three consecutive years, with the first one being the worst and the next two much milder. ……
Joe Vaclavik, grains broker at Chicago-based MF global, said from an agricultural commodity markets perspective, the biggest fear of a second La Nina would be the continuation of the current drought in the U.S. southern plains, causing further damage to the winter wheat crop. ….. Matt Rogers, President of Maryland-based Commodity Weather Group, warned that possible effects from the second round of La Nina could bring above-normal precipitation in eastern Australia, but would actually benefit the wheat and barley crops in terms of moisture. Yet, dryness concerns could be an issue for Argentina and southern Brazil, which would experience lower amounts of rainfall, causing damage to wheat, corn and soybean yields.
And Indian and Japanese forecasters have already called La Niña conditions.
The Indian Meteorological Department (IMD) has forecast an active wet spell for northwest India during the next five days and over east and adjoining central India during the next three days. This came about on a day when Japanese scientists assessed that the predicted return of La Nina conditions may already be happening.
Dr Jing-Jia Luo, Senior Scientist with the Climate Variation Predictability and Applicability Research Programme Research at RIGC, wrote to Business Lineon Friday that the La Nina condition is currently on the way back. This condition is forecast to persist until early next year, Dr Jing-Jia says, adding that a weak positive Indian Ocean Dipole (IOD), which mimics EL Nino-La Nina in the Indian Ocean, also may occur during the next few months.
Positive IOD refers to the warming of seas-surface temperatures in the western part of the Indian Ocean, and vice versa. Positive IOD has been found to favour a concurrent monsoon. Regional forecast from the RIGC said that the La Nina would bring cool to wet conditions over southern Africa, Australia, and Brazil during the southern hemisphere summer.
The confirming indicators for a La Niña event are accumulating – from the Indian monsoon to greater evaporation leading to increased rains expected in the Western Pacific in Australia, less rain in the Eastern Pacific on the western coast of S. America (coastal Chile and Peru) but increased rain on the east coast in southern Brazil and northern Argentina.
The k2p blog 