In the opening session of the 57th annual Beltwide Cotton Conferences in Orlando, Florida, Wednesday, David Zierden, a climatologist at the University of Florida noted the Cotton Belt's bout with drier and warmer than normal weather is probably not over.
Zierden explains the La Nina event currently underway in the Pacific Ocean waters directly south of the U.S. and Mexico and extending westward past the International Date Line, are responsible for shoving the more normal jet stream and storm track far into the northern U.S. states throughout the winter months. Those prevailing winds tend to keep turbulent weather -- and precipitation -- in the Northern Corn Belt and throughout the Ohio River Valley, rather than triggering thunderstorms and rain with storms across the Southern Plains into the South.
Zierden says La Nina events usually last 2-3 years, whereas the typical El Nino (warmer than normal sea temperatures in the Pacific from Panama to the International Date Line) have an average life span over the past century of about a year.
While the lack of moisture is never what a farmer wants to hear (unless there's a flood occurring) Zierden says statistics and computer models indicate cotton producers have a good chance of helping themselves to higher yields by planting earlier in La Nina years -- to get the stand up before extreme drought sets in, and to take advantage of the summer rains that do occur periodically during La Nina phases. "The correlation of dry weather in the U.S. and La Nina tends to break up during the summer months, and is not as strong as it is throughout the winter," Zierden explained. "What we find is throughout the summer of La Nina years, the rainfall across a given area of the South or Southeast is a mixed bag, not something you can confidently predict will be wet or dry."
Other comments during the opening session of the largest cotton gathering of the year, pointed to the devastating effects of this year's La Nina event on the 2011 U.S. cotton crop -- where, despite optimism during planting, nearly a third of the crop was lost or abandoned in Oklahoma and Texas because of extended periods of high temperatures and no rainfall.
For more information on El Nino and La Nina statistics gathered by Zierden and his associates visit EL NINO.