January 2015


Period: From January 2015      Issued on 14.01.2015 using data to the end of December

Summary

There is currently no strong indication of river flows or groundwater levels being substantially above- or below-normal in early 2015. For both the one and three month outlook, the most likely outcome is for normal river flows and groundwater levels to dominate across the UK.  Above-normal flows and levels are likely in some localised areas, but there is no strong indication of these conditions being widespread; meteorological forecasts slightly favour above- rather than below-average rainfall over the next three months, but there is a wide range of uncertainty in these projections.

Rainfall

Latest predictions for UK-mean precipitation favour near- to below-average rainfall for January. For January-February-March as a whole, although uncertainty is large, there is a slight preference for near- to above-average precipitation. The probability that UK precipitation for January-February-March will fall into the driest five equal categories is between 15% and 20% and the probability that it will fall into the wettest of five equal categories is around 20% (the 1981-2010 probability for each of these categories is 20%).

River flows

River flows in December were in the normal range across much of the UK, and moderately above in some catchments. The exception was in the far southwest of England where below normal flows were registered. Looking ahead, there is no strong signal towards above- or below-normal flows. The most likely outcome for January is for normal flows, across all parts of the UK, and this is also the expectation for the next three months. Above-normal flows may persist through January in some catchments which experienced higher flows in December, but generally flows are most likely to be in the normal range in early 2015.

Groundwater

December groundwater levels were in the normal range or above. Levels were normal across the majority of the Chalk outcrop, but above normal in a few boreholes in southeast and  northeast England. For other aquifers, levels were also normal or higher, with above normal levels in the Permo-Triassic sandstone of the Midlands. The one-month ahead outlook is for broadly similar patterns: normal levels are likely to be prevalent across the country, but above-normal levels are likely in localised parts of the Chalk and in other aquifers in central England. The three-month outlook is for a very similar picture.

Further information - January 2015

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