A system for hydrometeorological seasonal forecasting was developed to estimate available water resources in the coming months and predict droughts and other extreme climatological events. The system makes regular, high-resolution precipitation and temperature forecasts available to the public.

The sustainable distribution and management of water resources in semi-arid regions is becoming more and more complex, particularly due to climate change and population growth. As a result, the timely (i.e. well before periods of little or high precipitation) development of actions and management strategies is getting more and more crucial. Otherwise there is a risk of crop failures or shortages in the drinking water supply due to droughts and dry periods or floods due to heavy rainfall, which can cause a great deal of destruction. Action must be planned and taken as early as possible, which is why seasonal forecasts with forecast horizons of up to 12 months are increasingly used to support decision-making. However, the raw forecasts of the meteorological services cannot be used directly because they have too coarse a spatial resolution and are subject to model errors. We have developed a system that adapts (regionalises) the seasonal forecasts of the European Centre for Medium Range Weather Forecasts (ECMWF) to various climatically sensitive target regions and substantially improves the quality of the forecasts. In addition to the current forecasts, our system uses information from the past, so that statements can also be made about dry, humid, warm or cold periods. These categorical predictions are essential for water managers and decision-makers to assess water availability over the coming months. Our ensemble forecasts are published on the 7th of each month (i.e. approx. 2 days after publication of the ECMWF forecasts) via the data portal of the KIT Campus Alpin. Selected forecast variables are also displayed via an online system that was developed in cooperation with the geo-information company GAF AG.