The appearance of climate change in the form of extreme weather conditions is not a new challenge to the world. Water has been always an important need in any sector of human activity. In recent years the importance has increased especially in arid and / or semi-arid regions where water resources have become increasingly scarce. Though the importance is very much pertinent in drylands, the opinion of most of the researchers is that the irrigated regions of the country behold the relevance as world food production from irrigated agriculture represents more than 40 % of the total. This book illustrates natural water cycle (i.e. hydrological cycle), recent advances in hydrometeorological predictions, with an emphasis on modern forecasting techniques and meteorological observations. The topic of hydrometeorology includes a broad range of areas, such as weather radar, satellite and other monitoring techniques, flow routing, hydraulic models, rainfall-runoff, and Mathematical Weather Predictions. Primary applications of hydrometeorology include drought forecasting, flood forecasting, reservoir management, climate change assessment, water quality and water resources studies. Therefore, this book is intended for development students, researchers, policymakers, progressive farmers, and media peoples interested in water management and hydrometeorology under change in climate.