Latest outlook


Period: From March 2017      Issued on 10.03.2017 using data to the end of February 2017

Summary

The one month outlook indicates flows are likely to be in the normal range for much of the country, but with normal to above normal flows in parts of northern Britain which received higher rainfall in February (the wet start to March increases the likelihood of flows being above normal) and normal to below normal flows in south-east England. The outlook is for normal to below normal flows and groundwater levels to persist in south-east England over the next three months, with below normal flows and levels most likely across the Chalk aquifer. Elsewhere, flows and levels are most likely to be in the normal range over the next three months.

Rainfall

Rainfall in February was moderately above average for the UK as a whole. It was drier than average in south-west England, parts of central England and the far north of Scotland, but significantly wetter than average in north Wales and parts of northern England and Scotland.

The rainfall outlook for March (issued by the Met Office on 23rd February) indicates that above- and below-average precipitation are almost equally probable. For March-April-May as a whole, above-average precipitation is slightly more probable than below-average. The probability that UK-average precipitation for March-April-May will fall into the driest of five equal categories is 15% and the probability that it will fall into the wettest of five equal categories is between 20% and 25% (the 1981-2010 probability for each of these categories is 20%).

River flows

River flows in February were in the normal range across much of the country, with below normal flows in some catchments in south-east England and the far north of Scotland, and above normal flows elsewhere in Scotland, mainly the south-west.

The one month outlook favours a continuation of normal flows in many areas, but with normal to above normal flows in parts of northern and western Britain, and normal to below normal flows in south-east England – with below normal flows more likely in groundwater-dominated catchments across the Chalk aquifer. In the south-east, this situation is likely to continue for the next three months. Elsewhere, normal flows are most likely over the next three months. 

Groundwater

While February saw some delayed recharge, groundwater levels across the southern and eastern Chalk remained below normal for February.  Levels in other aquifers were more mixed, although mostly normal or below normal.

The outlook suggests that groundwater levels across the Chalk aquifer are likely to remain normal to below normal for the next one to three months. The signal for below normal levels is stronger for the three month period than for March; while the climate forecast slightly favours wetter conditions,  there is a significant shift towards warmth, meaning higher evapotranspiration. In other aquifers a mixed picture emerges: normal levels predominate but below normal levels are likely to persist in some areas, and above normal levels are likely in some northern aquifers.

Further information - March 2017

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