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Note: HRES and Ensemble Control Forecast (ex-HRES) are scientifically, structurally and computationally identical.  With effect from Cy49r1, Ensemble Control Forecast (ex-HRES) output is equivalent to HRES output where shown in the diagrams.   At the time of the diagrams, HRES had resolution of 9km and ensemble members had a resolution of 18km.

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Surface winds

1.1.1. Mean winds

Typically the winds in the boundary layer are backed and decreased from the geostrophic values through the retarding action of surface friction.  Frictional retardation varies according to the differing surface features – quite high over rugged terrain or forests, moderate over open grassland or farmland, small over featureless tundra or deserts.  Over open water the friction varies according to the size of waves which in turn varies in part according to the wind itself – generally minimal over smooth water but significant where swell or wind waves are high (e.g. near major storms).  

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• See the impact of Cycle 47R3 on representation of wind gusts.
• Read more on parametrisation of convective gusts.
• Read about new EFI parameters for forecasting severe convection (which contains informative case studies, where there are references to gusts associated with active convective systems).
• Watch a comprehensive lecture on Model Physics: Concepts, Practice and Products (36sec delay in start, winds and gusts discussed from 31min15sec to 36min40sec).
• Read a 2015 paper on extra-tropical Cyclones and the strong wind phenomena that are associated

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