River. Image by Tim Hill from Pixabay
Latest Outlook
Outlook map for September 2021

September 2021 Hydrological Outlook

Period: From September 2021      Issued on 09.09.2021 using data to the end of August 2021

River flows in northern and western areas are likely to be normal to below normal in both September and September-November, whereas river flows in the south-east are likely to be normal to above normal over both timeframes. Groundwater levels in most boreholes of the UK are likely to be normal to above normal in September, but normal to below normal during September-November.

Rainfall:

Rainfall in August was below average across the vast majority of the UK, notably so in parts of central and eastern England, and the Scottish Highlands.  Above average rainfall was generally limited to parts of Northern Ireland and eastern Scotland.
The rainfall outlook for the UK for September (issued by the Met Office on 23.08.2021) is that near-average rainfall is the most likely outcome. For September-October-November as a whole, it is more likely to be dry than wet.

River flows:

River flows in August were generally below average across Northern Ireland, Wales, and most of England (except for the south-east).  Flows were notably low in catchments draining the northern Pennines and in western Wales.
The outlook for September is for normal to above normal river flows in the south-east and for normal to below normal river flows further north and west.  Although the signal is dampened, this pattern is also suggested for the September-November timeframe.

Groundwater:

Groundwater levels in August were normal to above normal across most of the UK, and exceptionally high in some localised boreholes along the south coast and in parts of northern Britain.  Conversely, levels were low in Northern Ireland and south Wales.
The outlook for September is for normal to above normal groundwater levels across most of the UK.  Conversely, levels are likely to be below normal in south Wales.  Over the September-November timeframe, the outlook is for normal to below normal groundwater levels, though some boreholes in southern England remain likely to be above normal.

Note that due to continuing issues with data access, no data are available for Scotland.