An Analysis of Users' Trust in Long-Range Weather Forecasting for Southwestern California Before and After the 2015-2016 El Niño

Sea-surface temperatures in the Oceanic Niño Index showed that the 2015-2016 El Niño tied with the 1997-1998 El Niño as the strongest on record. Based on analogs of historical El Niño events, most scientists, including the Climate Prediction Center, had considerable confidence that southwestern California would observe above normal precipitation for the 2015-2016 winter season. However, southwestern California observed only 40 to 70 percent of normal precipitation during the period.

This analysis will determine if the inaccurate long-range winter precipitation forecast affected decision makers and other users’ trust of long-range weather forecasting. To determine the results, an informal survey was conducted with twenty National Weather Service San Diego area partnering agencies. The author’s hypothesis is that although the long-range forecast of above normal precipitation for the 2015-2016 winter season did not verify, the survey responses will show users have varying amounts of value in medium to long-range weather forecasts. If correct, then long-range seasonal forecasts will remain a useful tool for planning and preparation purposes.