A brief account is given of the case work undertaken as part of the Summer Study Week on ‘Extra-tropical Cyclones’ held in Reading during July 1996. It is shown that different approximate methods of assessing synoptic-scale vertical velocity can give widely differing results. Computation of the full quasi-geostrophically forced vertical velocity is recommended as a more informative procedure. Forecasts for the track of an explosively deepening north Atlantic cyclone are compared at different lead times. The comparison encompasses raw model forecasts and model forecasts adjusted by groups of case work participants. The groups achieved a large improvement over a model forecast at the 2-3 day lead time, but only marginal improvements thereafter. It is suggested that improved understanding of development mechanisms would enable the forecaster to appreciate better the range of possible outcomes in cyclogenetic situations.