June 2016


Period: From June 2016      Issued on 10.06.2016 using data to the end of May 2016

Summary

The outlook for June is for normal to below normal river flows for northern and western areas of the UK, following a dry spring and a dry start to June. In parts of southern and eastern England, where spring has been wetter, June flows and groundwater levels are likely to be normal to above normal. Over the next three months, flows are likely to be normal to below normal across much of the country. In places where groundwater levels are currently above normal, such as central southern England and parts of northern Britain, this situation is likely to persist through the summer. This is likely to also lead to above normal summer flows in some groundwater dominated catchments in the south and east.  

Rainfall

Rainfall for May was average for the UK (102% of the 1971-2000 average). Northern England, eastern Scotland and southwest England were dry,  while parts of southern England saw above average rainfall.

The rainfall outlook (released by the Met Office on 26th May 2016) for June suggests above-average precipitation is slightly more probable than below-average. For June-July-August as a whole, there are only relatively weak influences acting to modify the likelihood of above- and below-normal from what would be expected. The probability that UK precipitation for June-July-August will fall into the driest of five equal categories is around 20% and the probability that it will fall into the wettest of these categories is also around 20% (the 1981-2010 probability for each of these categories is 20%).

River flows

River flows in May were mostly in the normal range, with below normal flows in southwest England and some other western catchments, contrasting with above normal flows in central southern England.

The one month outlook is for normal to below normal flows in northern and western areas, with below normal flows most likely in southwest England and parts of northern England and Scotland.  Flows are likely to be normal to above normal in southeast England and East Anglia. The three month outlook is for normal to below normal flows across much of the UK, with an elevated likelihood of notably or exceptionally low flows in northwest Britain. However, this is very uncertain given the low predictability of rainfall in summer. In southeast England, above normal river flows in some groundwater-fed catchments are likely to persist through the summer.

Groundwater

Groundwater levels in May were normal to above normal, with above normal levels concentrated in southern central England and the Permo-Triassic sandstone of northern Britain, where levels remained notably high.

The one month outlook is for a similar pattern to continue in June, with above normal levels in parts of the southern Chalk contrasting with normal levels elsewhere in the aquifer, and notably high levels in the Permo-Triassic sandstone of the north.  As expected in the summer, when groundwater forecasts are generally insensitive to rainfall, the three month outlook is broadly similar as seasonal groundwater recessions continue through the summer. However, above normal levels are likely to be less prevalent in the Chalk, and levels in the northern Permo-Triassic sandstone are likely to fall from notably high to above normal.

Further information - June 2016

Comprehensive further information that supports the production of the Hydrological Outlook UK is available here.