El Niño Conditions Expected to Strengthen
and Last Through the Winter of 2009-2010

The Climate Prediction Center has reported that El Niño conditions have developed in the tropical Pacific and are expected to strengthen and last into early 2010. What does this mean for western and central Oklahoma and western north Texas? Historical sea surface temperature analysis, dating back to the early 1950s, indicate each El Niño event varies in the degree of strength and duration, so the answer is complex. El Niño episodes are classified into three categories: strong, moderate and weak.

Four cases of each were studied and arranged according to geographical climate divisions. Of the three categories, the strong episode provides the strongest indicator that above normal precipitation can be expected during the winter months. The weak to moderate episodes studied do not provide as much insight. In general, the weak to moderate episodes bring nearly an equal chance of receiving below or above average precipitation across the entire region of western and central Oklahoma and western north Texas.