December 26, 2011

Nebraska enters second winter with La Nina conditions


Flooded corn field west of Ashland, Nebraska.  Photo by Craig Chandler / University CommunicationsDrovers CattleNetwork reported last week that Nebraska is entering its second straight winter with La Nina conditions in the Equatorial Pacific, but the Nebraska state climatologist said that won't necessarily mean the same kind of winter in 2012.

With the redevelopment of La Nina conditions this fall, there was considerable discussion among climatologists as to whether 2011 winter trends would return in force during this upcoming winter, said Al Dutcher, Nebraska state climatologist.

So far the answer is no, he said.

"In layman terms, the current La Nina is rated as a weak to moderate event, compared to last year's rating of exceptionally strong," he said.

Essentially, the upper air lows moving across Texas are robbing the northward transport of moisture into the northern Plains, he said. As a result, the upper Plains trough moisture patterns are dependent on Pacific Ocean moisture instead of the Gulf of Mexico.

"Unfortunately, this Pacific moisture is intercepted by the northern Rockies and Cascades before it reaches the northern plains," Dutcher said. "During the past 30 to 45 days, more moisture has fallen across portions of south central Kansas, eastern Oklahoma, and north central through northeast than fell in the previous 12 month period.

"Nebraska has been caught dead center between these two pieces of energy," Dutcher said.

If the southern plains low begins to lift northeastward before the northern plains trough arrives, enough moisture moves northward to produce rain and/or snow. If the northern Plains trough wins out, then a dry and cold pattern materializes and the southern plains moisture gets shunted east of Nebraska, he said.

What does this mean for corn farmers?

The two competing forces of energy eventually merge east into a strong upper air trough east of Nebraska, which results in heavy moisture events for the eastern Corn Belt.

"As long as this pattern continues, areas of southwest through east central Nebraska will likely have the best opportunity to receive normal to above normal moisture," Dutcher said.

Read more about the La Nina conditions, here.

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