La Nina could mean dry summer in Midwest and Plains

CHICAGO (Reuters) - A La Nina weather pattern could be in store for spring and summer, which could make it a dry growing season for grains and soybeans in the US Midwest and Plains, a private forecaster predicted Friday.

The CFS forecasting model, a leading indicator of long-term weather, on Friday showed that La Nina -- an abnormal weather pattern of cooling sea surface waters in the Pacific Ocean -- would begin in April.

"This was the first decisive run suggesting that La Nina would evolve in April and last the rest of the year," said Drew Lerner, agricultural meteorologist and president of World Weather Inc. in Kansas City.

The forecast ignited a rally in Chicago Board of Trade grain and soybean markets on Friday, traders said.

La Nina can trigger below-normal rainfall but doesn't necessarily mean drought, though there's already a bias for a drier summer, he said.

"You throw a La Nina into it, it tends to make the drier biases more significant for the Corn Belt and Plains," Lerner said.

Grain markets react to La Ninas as there's a general mentality among traders that the weather anomaly creates summer droughts, he added.

"All the major drought years tend be La Nina ... 1988 was a La Nina," he pointed out.

CBOT new-crop December corn was up 7 cents at $4.11-1/2 per bushel past midday. New-crop November soybeans rose 6 cents to $8.16-1/2 a bushel and new-crop July wheat shot up 11-1/2 cents to $4.89-3/4.