The Impact of ENSO on Extreme Winter Weather over the United States

Siegfried Schubert



In this study we examine the impact of ENSO on extreme winter storms over the continental United States. The analysis is based on 50 years of daily precipitation observations, NCEP/NCAR reanalyses of heights and winds, and 9 fifty-year NASA Seasonal to Interannual Prediction Project (NSIPP) model simulations forced with observed sea surface temperatures. The focus is on the tail of the probability density function of daily precipitation, and how it is impacted by EL Nino and La Nina conditions. The observations show clear linkages between ENSO and extreme weather systems that impact the west coast and those that form over the Gulf of Mexico and affect much of the east coast. The NSIPP model shows similar weather/ENSO linkages suggesting the possibility of useful probablistic predictions of extreme weather.