March 2015


Period: From March 2015      Issued on 10.03.2015 using data to the end of February

Summary

All indications are that river flows and groundwater levels are most likely to be in the normal range throughout the UK during March.

Some regional variation appears  for the three month period March to May. River flows in north-east Scotland are most likely to be below average, and there’s an increased probability of above average flows in  the most south-easterly corner of England, although here normal flows are the most likely outcome. Groundwater levels are also most likely to be above normal in this corner of England over this period, but further west  indications are for lower than normal levels in the Chalk aquifer of the Berkshire Downs and west Wessex.

Rainfall

The latest predictions for UK-mean precipitation favour below-average rainfall over above-average in March. For March-April-May, predictability is low and the forecast is largely indistinguishable from climatology, although with a slight preference for near- to below-average precipitation. The probability that UK precipitation for March-April-May will fall into the driest of our five categories is around 20% and the probability that it will fall into the wettest of our five categories is between 15% and 20% (the 1981-2010 probability for each of these categories is 20%).

River flows

Observed river flows during February were in the normal range across most of the UK with very few and isolated exceptions. This starting point, combined with a rainfall forecast close to climatology, means that normal conditions are most likely to persist into March and beyond. Some forecasts suggest a slight departure from this ubiquitous normality over the March to May period  with below normal flows being most likely in north-east Scotland, and an increased probability of above normal flows in the most south-east corner of England.

Note: These flows forecasts relate to long-term mean flows and not floods. Flood alerts and warning are in force on some rivers in Scotland as a consequence of the heavy rainfall in early March. Visit the SEPA web site (link below) for more information.

Groundwater

Groundwater levels during February generally remained in the normal range or above for the time of year despite overall falls in levels at many locations across the UK, with the exception of the Permo-Triassic sandstones which recorded above normal levels. Groundwater levels are likely to remain normal in most aquifers in both March and the coming three months. Although the three month outlook for the Chalk aquifer of the Berkshire Downs, west Wessex, Lincolnshire and Yorkshire suggests slightly below normal levels. If rainfall is significantly above average over three months groundwater levels in the far south and south-east may become notably high.

Further information - March 2015

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