Winnipeg (Resource News International) — La Nina conditions in the Pacific Ocean over the winter are seen as a potential indicator of large Canadian wheat yields the following summer.
Long-term weather conditions can be an inexact science, due to the sheer number of variables involved. But La Nina and El Nino conditions, which relate to Pacific Ocean surface-level water temperatures along the equator, are often directly linked to weather patterns in South America and Australia, meteorologist Mike Tannura of Chiacgo company T-storm Weather told the Canadian Wheat Board’s annual Grain World Conference here Tuesday.
However, the Rocky Mountains make it more difficult to find direct linkages between La Nina/El Nino and weather conditions in the U.S. Midwest or Canada’s Prairies, he added.
Looking at the major North American crops over the past 50 years, Tannura attempted to find a correlation between La Nina conditions in the winter and yields the following summer. In the U.S. he could find no correlation for corn, soybeans or wheat.
But in Canada, Tannura found that four of the five best-yielding years for wheat in Canada over the past 50 years, including 2008, came following strong La Nina conditions in January.
As a result, he thought the chances of above-average Canadian wheat yields are higher when there is a La Nina. However, La Nina conditions were also present prior to one of the five poorest-yielding years for Canadian wheat, showing that there can be many other factors determining actual weather patterns.
Below-normal water temperatures currently point to a moderate La Nina, said Tannura.
While he was reluctant to provide a longer-term weather outlook of his own, Tannura noted that the U.S. Climate Prediction Centre was currently forecasting average temperatures and precipitation for the U.S. Midwest over the June-to-August period.
Tannura said one potential problem area to watch in the U.S. was the hard red winter wheat belt of northern Texas and into Kansas, which is warmer than normal and in need of rain.