August was generally an unsettled month, with a characteristic mix of warm sunny weather and thundery showers. In northern and western areas rainfall was persistent and it was an exceptionally wet month, while in the southeast it was dry, especially later in the month. Overall it was nearly 1°C warmer than average and there were some hot spells, especially in the south-east later in the month. The downpours led to notable river flow responses in northern Britain, bringing widespread flood alerts and transport disruption, but few reported major impacts – with the exception of the incident at Toddbrook reservoir in the first few days, a response to the exceptional late July rainfall. August brings to a close a summer of marked contrasts between northern Britain, which saw exceptionally high flows and localised flooding incidents, and the English lowlands, where flows continued to recede towards late summer minima in some catchments. Groundwater levels were below normal across much of the Chalk and notably or exceptionally low in some boreholes. Overall, reservoir stocks at the national scale were above-average for the end of August, with only a few impoundments (Ardingly, Colliford and Roadford) having stocks appreciably below average. The current water resources situation is healthy at the national scale, but with notably low groundwater levels and river flows in the English Lowlands entering autumn (and a continuation of the late August dryness into early September) the 2019/2020 recharge season will be starting from a below-average baseline, with potential implications for the longer-term water resources outlook.
The full Hydrological Summary can be found here.