Prediction of near‐surface gusts generated by deep convection

An equation for the prediction of near‐surface gusts generated by convection is tested against observations and against simulations made with a model which resolves convectve clouds, in order to investigate the phenomenon, and to validate the equation in a range of convective regimes. These include two types of severe weather which affect the UK: mid‐latitude depressions and thunderstorms. The prediction equation works well in both convective regimes. Two processes are shown to be important. The first is the production of horizontal momentum by pressure gradient forces, as convective downdraughts are blocked by the surface and distorted to spread out horizontally. The second is the downward transport of horizontal momentum by the convective downdraughts, in the presence of vertical shear. The equation should be tested by forecasters, especially when deep convection occurs in conjunction with strong geostrophic winds. It could also be applied in Numerical Weather Prediction models to automate the prediction of convective gusts.