The science behind the Hydrological Outlook seasonal groundwater level forecasts

The Hydrological Outlook provides a forecast of groundwater levels (and river flows) across the UK over the next three months. To forecast groundwater levels the British Geological Survey uses models that simulate fluctuations in groundwater level at 25 sites across the UK. Each of these models is driven by rainfall and evaporation time-series and has been calibrated against past observations of groundwater level. To forecast groundwater levels the 1 and 3-month ahead climate forecasts produced by a Met Office climate model are used. These two climate forecasts are probabilistic and comprise an ensemble of up to 42 members. Consequently, a probabilistic groundwater level forecast is produced for each site. There will be a demonstration of the Hydrological Outlook web site and short talk on how the models are used to produce the forecasts and how the skill of the forecast has been tested.