Iowa farmers are taking careful note as a La Nina Watch is being issued by the Climate Prediction Center for the fall and winter months.

That relates to cooler sea surface temperatures in the Pacific Ocean which has an impact on weather across North America. Meteorologist Dennis Todey, director of the U.S.D.A.’s Midwest Climate Hub — based in Ames, says that prediction evolved quickly.

“La Nina looks like the most likely outcome of our three possibilities, La Nina, El Nino and neutral conditions,” Todey says. “La Nina is the most likely condition as we get out into September, October, November, all through the winter until February, March, April.” Todey says there are still questions about the possible impacts of this development.

“A number of the models vary from just marginal La Nina conditions to moderately strong ones,” Todey says. “There’s not a good consensus as to how strong this one will be, therefore, we’re kind of waffling on what the outlook is going to mean to us.” Todey says if a La Nina weather pattern develops, it could have more of an impact on winter weather.

“No where does CPC put in a below-average chance for temperature but they are saying mostly equal chances for below or above average,” Todey says. “You’re balancing this trend toward warmer winters with the La Nina conditions which have a little better probability of being cooler.” Todey says a La Nina system could also lead to more snow over the Midwest and Northern Plains this winter.

(By Jerry Oster, WNAX, Yankton)