The most damaging winds in a severe extratropical cyclone often occur just ahead of the evaporating ends of cloud filaments emanating from the so‐called cloud head. These winds are associated with low‐level jets (LLJs), sometimes occurring just above the boundary layer. The question then arises as to how the high momentum is transferred to the surface. An opportunity to address this question arose when the severe ‘St Jude's Day’ windstorm travelled across southern England on 28 October 2013. We have carried out a mesoanalysis of a network of 1 min resolution automatic weather stations and high‐resolution Doppler radar scans from the sensitive S‐band Chilbolton Advanced Meteorological Radar (CAMRa), along with satellite and radar network imagery and numerical weather prediction products. We show that, although the damaging winds occurred in a relatively dry region of the cyclone, there was evidence within the LLJ of abundant precipitation residues from shallow convective clouds that were evaporating in a localized region of descent. We find that pockets of high momentum were transported towards the surface by the few remaining actively precipitating convective clouds within the LLJ and also by precipitation‐free convection in the boundary layer that was able to entrain evaporatively cooled air from the LLJ. The boundary‐layer convection was organized in along‐wind rolls separated by 500 to about 3000 m, the spacing varying according to the vertical extent of the convection. The spacing was greatest where the strongest winds penetrated to the surface. A run with a medium‐resolution version of the Weather Research and Forecasting (WRF) model was able to reproduce the properties of the observed LLJ. It confirmed the LLJ to be a sting jet, which descended over the leading edge of a weaker cold‐conveyor‐belt jet.

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One contribution of 16 to a theme issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse' .

On 1 July 2015, severe hailstorms developed over northern England. One storm tracked across an area with a dense network of privately owned (i.e. 'home') automatic weather stations (AWSs), permitting analysis of surface wind, pressure and temperature fields on the storm scale. The home AWS data were filtered and corrected by comparison with data from the nearest United Kingdom Met Office AWS, where measurements are made with calibrated sensors having known error characteristics. A time-compositing technique was applied to the corrected home AWS data, before interpolation onto a 1 km grid using Delaunay triangulation. The resulting analyses were compared with radar data to assess their quality and provide insights into storm evolution and structure. Surface analyses resolved a pressure anomaly couplet on the right, rear flank of the storm, gust fronts, and regions of inflow and outflow. The pressure couplet was closely collocated with the radar-observed mid-level updraught position, with the mesolow (mesohigh) situated underneath the downshear (upshear) flank. The mesolow was also collocated with the strongest inflow winds. Structural features in the surface analyses (e.g. forward-and rear-flank gust fronts and a prominent inflow notch) compared well with radar-observed structures, and conformed closely to established conceptual models of supercell storm morphology. Further insight into storm structure was gained by synthesis of the surface analyses, Doppler radar data, crowd-sourced hail reports and eyewitness photographs. Collectively, the results demonstrate that the gridded home AWS data may be of sufficient quality for use in post-event studies of severe thunderstorms and, potentially, in the operational forecasting environment.Fine-scale analysis of a hailstorm