One of the topics discussed during a NOAA webinar on the Midwest and Central Plains drought outlook Thursday the prospect for El Nino during the 2014 crop season. El Nino has been in the news a lot recently, and there have been many comments suggesting that the onset of this feature would be soon enough to bring major drought relief to the Far West, the southwestern Plains, and provide mild conditions for corn pollination in the Corn Belt. That's quite a "to-do" list for an atmospheric event.
But, can all these things be accomplished by a feature that is still months away from fruition? After all, the Pacific equatorial sea surface temperatures are less than a half-degree Celsius above normal. In the same vein, the barometric pressure feature known as the Southern Oscillation Index (SOI) is also in a solid "neutral" category; the Friday, April 18 30-day SOI calculation was +0.5, and the 90-day number was -2.1. Those values are well within the "neutral" range. Still, a large pool of very warm water at the sub-surface levels is moving through the eastern Pacific, and is forecast to the be catalyst for an El Nino event to form later this year. That, of course, begs the question of "when"?
South Dakota state climatologist Dr. Dennis Todey discussed that question of "when will El Nino form?" during the NOAA webinar. He suggested that by July and August "...we should see some kind of El Nino signal by that point with some influence on (corn and soybean) yield." If that occurs, Todey looks for the El Nino effect to be one of reducing stress. "Years with El Nino typically have near-normal temperatures," he said.
But, what about this development in relation to the Plains winter wheat crop? Todey was not as optimistic on this question. "I don't think that El Nino will form in time to impact winter wheat," he said. And on a similar note, Todey addressed the harsh drought in California. "I know that in California, there is the hope that El Nino will bring rain for drought alleviation, but I don't see that happening until fall and winter," he said.
Also during the webinar, National Weather Service meteorologist John Eise reminded webinar attendees that, just because the Pacific conditions may attain El Nino thresholds for temperature and barometric pressure, the actual impact in terms of weather could still take time to develop. "There is a lag response by the atmosphere," Eise said. "It takes time for things to adjust and be felt."
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