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Predicting Drought at regional baseClick to edit Master title style meteorological drought is never the result of a single cause. It is the result of many causes, often synergisticin nature. too many variables:- air-sea interactions- soil moisture and land surface processes,- topography,• Click to edit Master text styles- the accumulated influence of dynamically unstable synoptic weather systems at the global scale.- differs by region, season, and climatic regime• Second levelThe Big Picture: Global Weather Patterns interacting systems or teleconnections El Niño/Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO)• Third levelThe Little Picture: High Pressure• Fourth level The immediate cause of drought is the predominant sinking motion of air (subsidence) that results incompressional warming or high pressure,- inhibits cloud formation• Fifth level- results in lower relative humidity and less precipitation. Regions under the influence of semipermanent highpressure are usually deserts, such as the Sahara. Most climatic regions experience varying degrees of dominance by high pressure, often depending on theseason. Prolonged droughts occur when large-scale anomalies in atmospheric circulation patterns persist for monthsor seasons (or longer).WMODrought and Desertification Workshop, Alanya, 14-16 November 20063TSMS