U.S. weather officials predict that El Nino, the periodic warming of the tropical Pacific Ocean surface that influences global weather patterns, will begin forming this summer. Its local impact could range from more precipitation this fall and winter to a more expensive cup of coffee next year.
There is a 65 percent chance El Nino will develop by the end of summer, according to the National Oceanic and Atmospheric Administration's Climate Prediction Center. The likelihood increases to 80 percent by the end of the year.
If an El Nino arrives this year, "the effects we feel in the United States are probably going to be more in the fall and winter," said Pat Spoden, science and operations officer with the National Weather Service in Paducah. Its impact typically is smaller in summer months when subtropical and polar jet streams interact less often.
An El Nino normally means warmer and drier winters across the northern plains, wetter conditions on the West Coast and cooler and wetter conditions in the southern states, he said.
"There's a slight increase in general rainfall patterns in the Ohio Valley with El Nino," said Spoden.
One positive effect of El Nino is that it tends to suppress hurricane activity along the Atlantic Coast.
The last El Nino occurred in 2009-10. A contrasting climatic phenomenon called La Nina, marked by cooler Pacific surface temperatures, has mostly opposite effects on weather in the U.S. The most recent La Nina came in 2010-11.
Commodity analysts pay attention to El Nino because of its potential impact on crops around the world.
"Asia and Australia usually see droughts during El Nino years, which can be damaging to the local agriculture," said Kaisa Stucke, research associate with Confluence Investment Management in St. Louis.
"Indonesia and the Philippines seem to be close to the epicenter of El Nino-induced droughts. The lack of rain caused by cooler ocean water can damage coffee, cocoa and palm oil yields."
On the other hand, plentiful rainfall in the spring in southern Brazil, Argentina and Uruguay can lead to better yields from summer crops. Soybean and livestock yields are likely to improve due to increased rainfall.
"In general, soft-commodity prices rally between 10 (percent to) 40 percent during El Nino periods," Stucke said. "Sugar and coffee prices have risen the most during the last six El Nino events as their production is concentrated in areas mostly affected by droughts."
The price of that morning cup of coffee is one effect El Nino could have no matter where you live.
"Coffee prices have appreciated 60 percent this year (due mostly to drought conditions in Brazil)," Stucke said. "On the back end of those higher prices, if there was a worse crop next year ... that could have a huge effect on the coffee market."
Contact David Zoeller, a Paducah Sun staff writer, at 270-575-8676.