Only 5 days prior to this major event, Sheffield had experienced another, similar, severe windstorm; although the only other comparable events happened 5 years and 60 years previously, suggesting that the return time for such a storm is rather high, and that the conditions necessary for its occurrence are not common.
A previous study (Aanensen and Sawyer, Nature, Feb. 1963), published soon after the event and making use of two-dimensional linear theory, suggested that the damage was caused by Sheffield being located underneath the trough of a lee wave. For the present study, results from the Weather Research and Forecasting (WRF) model will be presented. Initialised with ERA-40 re-analyses, the model has been run in nested mode with high resolution (1km) over the north of England. The complex, three-dimensional nature of the lee-wave windstorm was reproduced, and results will be shown for Sheffield and surrounding areas, and the mechanism of generation will be investigated. The severe damage attributed to this storm will be shown to be due not only to high mean winds, but to transient, rotor-like features, causing the very localised nature of the damaging effects of the wind storm.
An important aspect of this work, giving it operational as well as historical and scientific interest, is whether the synoptic situation leading to the gales would be interpreted by the latest models as being conducive to the generation of such a windstorm - the return times suggesting that another such event could well occur in the future.