November 2014


Period: From November 2014      Issued on 12.11.2014 using data to the end of October

Summary

After the driest September on record, unsettled conditions dominated October and most parts of the UK received substantially above-average rainfall.  The net result is that October river flows  were in the normal range across the majority of the country and groundwater levels were mostly normal or above normal. The one month outlook for November is for both river flows and groundwater levels to be within the normal range across much of the UK. River flows and groundwater levels in parts of southeast England are likely to  be above normal, as are groundwater levels in some other parts of  England (see map). There is  also an increased likelihood of above normal flows in Scotland. The three month outlook indicates normal conditions are most likely for both river flows and groundwater, suggesting the water resource situation will be favourable entering 2015. 

Rainfall

Latest predictions for UK-mean precipitation favour near- or above-average rainfall for November and for the November-December-January period as a whole. The probability that UK precipitation for November-December-January will fall into the driest of five equal categories is around 15% and the probability that it will fall into the wettest of these categories is around 25% (the 1981-2010 probability for each of these categories is 20%.

River flows

October river flows were in the normal range across almost the whole of the UK, with the exception of parts of northern Scotland and some catchments in eastern England, where flows were above normal, and a few isolated catchments elsewhere with below normal flows. The one month outlook is for a similar pattern. The most likely outcome is for river flows to be in the normal range in all regions, except for parts of central and southeast England where above normal flows are most likely. There is also a raised likelihood of above-normal river flows for much of Scotland where the end of October was very wet. The wet start to November provides supporting evidence that flows for the month as a whole will be normal to above normal. For the three month outlook, the situation is broadly similar, with normal flows the most likely outcome across the whole of the UK.

Groundwater

October groundwater levels were in the normal range across the greater part of the Chalk aquifer, but with above normal levels in some southeastern boreholes and below normal levels in central southern England. Levels in the Permo-Triassic sandstone were mostly above normal (exceptionally so in some cases). The one month outlook is for broadly similar patterns. Normal levels are likely across much of the Chalk, but with above normal levels in some central and eastern parts of the aquifer. Above normal levels are very likely to persist in western outcrops of the Permo-Triassic sandstone. Over the three month timeframe, the situation is similar, although normal levels are likely to be more prevalent than above normal.