Authors: Mary Knapp, Christopher Redmond

As August fades, interest is growing in the fall weather outlook. The National Oceanic and Atmospheric Administration’s Climate Prediction Center has just released its September-November outlook:

The strongest signal is in the temperature outlook. However, there are several difficulties with this forecast. First is that this forecast is the average for the 3 months of September, October, and November. If temperatures are warmer than normal in September, but cooler than normal in November, you could still see a warmer-than-normal 3-month average. Another difficulty is that the outlook doesn’t indicate the degree of departure. Warmer-than-normal conditions could be by just a tenth of a degree, or the departure could reach 10 degrees (although the latter is not likely). The third difficulty is most visible in the precipitation outlook, where equal chances dominate. Autumn is a shoulder season, where we switch dominate weather patterns, and these are the most difficult patterns to forecast accurately.

An additional difficulty is that one of the major global patterns that helps increase the accuracy of the forecast is in a neutral phase. That, of course, is the ENSO -- El Niño Southern Oscillation. The ENSO, which currently shows sea surface temperature below normal, is expected to develop into La Niña conditions by late fall. However, the La Niña isn’t expected to be strong, and its influence in Kansas during the winter is only weak.

Changes in the forecast and outlooks can be found on the Climate Prediction Website: http://www.cpc.ncep.noaa.gov/

Updates on Kansas climate can be found at http://climate.k-state.edu/

And updates on current weather can be found at http://mesonet.k-state.edu/

Mary Knapp, Weather Data Library

Christopher Redmond, Weather Data Library