The Climate Prediction Center released their latest monthly and seasonal forecast today. We are still in between El Niño and La Niña. According to CPC, “La Niña is favored to develop during August – October 2016, with about a 55-60% chance of La Niña during the fall and winter 2016-17.”
For August, the southern half of Illinois has an increased chance of above-normal temperatures (top row in the figure). The northern half has “EC” or equal chance of above, below, or near-normal temperatures. Western Illinois is part of a larger area in the western Corn Belt with an increased chance of above-normal rainfall. The rest of Illinois is in the “EC” category.
For August-October (bottom row), the entire US has an increased chance of above-normal temperatures. Illinois has equal chances of above, below, and near-normal precipitation. The increased chance of above-normal temperatures for Illinois continues in the September-November and October-December outlooks before it goes away this winter.
So bottom line – possibly wetter in western IL and warmer in southern IL in August (compared to normal) and a possibly warmer fall. Personally, I wouldn’t pay too much attention to this winter’s forecast until this La Niña shows up or not.
Temperature and precipitation normals refer to the 1981-2010 averages.