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'Drought characteristics in the Central Plains: putting the 2011-2012 drought in perspective'
Daniel Barandiaran (dbarandiaran@gmail.com), Utah State University

This study characterizes the Central/Southern Plains drought during the years of 2011 and 2012. Using EOF analysis on seasonal precipitation we decompose the annual cycle into various seasonal components, and define the analysis region based upon where a distinct spring maximum is present – i.e. Oklahoma & NE Texas. Focusing on this region, we find that drought occurrences possess a mixture of signals. Annual and spring components dominate the region, and are accompanied by smaller contributions coming from fluctuations in fall and winter precipitation. The circulation anomalies associated with these seasonal drought patterns exhibit the distinct form of a “short-wave train” that stretches across North America and adjacent oceans. This circulation pattern is distinct from the common Pacific-North America (PNA) pattern consisting of longer atmospheric waves and triggered by La Nina conditions. In 2011 there was a persistent precipitation deficit for the whole year, while during 2012 the winter season was actually wetter than normal but the spring was considerably drier. We also evaluate the performance of the NMME models in forecasting these drought events. Dissemination strategies to appropriate management and government agencies of information such as the possibility of further back-to-back drought will be discussed.