October was a typically autumnal month with a mixture of settled weather and stormy spells, but with a wintry period at month-end. Although temperatures were near average, it was unseasonably warm in the second week; a high of 26.5°C was recorded at Donna Nook (Lincolnshire) on the 13th. Rainfall for the UK was moderately below average with the largest deficits in Northern Ireland, central and southern England and eastern Scotland. October soil moisture deficits (SMDs) were above average across most of the UK and in Northern Ireland they were the third highest in a series from 1961. Above average river flows were restricted to southern Wales and northern Scotland; elsewhere flows were generally in the normal range with some notably below average flows in catchments in southern and eastern Britain. Groundwater levels generally continued to recede and were in the normal range or below for the time of year, with notably low levels in parts of the Chalk. Reservoir stocks continued to fall at most impoundments in England and Northern Ireland and were more than 25% below the October average in some instances (e.g. 33% below average for Derwent Valley, 29% below average for Clatworthy). Despite substantial increases in Wales, late October reservoir storage for England & Wales was the lowest for the time of year since 2003. Given current reservoir stocks, locally depressed river flows and a delay in the onset of groundwater recharge, rainfall through the remainder of autumn and winter will be critical in determining the water resources outlook for 2019.
The full Hydrological Summary can be found here.