The UK Hydrological Outlook provides an insight into future hydrological conditions across the UK. Specifically, it describes likely trajectories for river flows and groundwater levels on a monthly basis, with a particular focus on the next three months.
Well-established monitoring programmes provide the current status of both river flows and groundwater levels at many sites across the UK, and data from these programmes provide the starting point for the UK Hydrological Outlook. A number of techniques are used to project forwards from the current state and results from these are used to produce a summary that includes a highlights map.
Much of the information in the UK Hydrological Outlook is presented with reference to normal conditions, rather than to specific figures. Normal conditions vary with the time of year and characteristics of the river or groundwater body. More information on the variability of river flows and groundwater levels can be found on the National River Flow Archive and National Groundwater Level Archive.
As with all attempts to look into the future, it must be recognised that there is considerable uncertainty associated with the UK Hydrological Outlook. This uncertainty depends on current conditions and other factors such as the time of year and location within the UK.