Sanders proposes to complete two case studys in which significant weather features are present which have not been intensively analyzed previously, and a third study in which the prediction skills of two operational Numerical Weather Prediction models are assessed and compared. The region covered in the third study is the western North Atlantic, and the period of concern is the winter of 1988-89, when a significantly enhanced observational system was deployed at sea as part of project ERICA. ERICA was mounted after Sanders' prior pioneering research focussed attention on the weather phenomenon he labelled "explosive marine cyclogenesis". The subject phenomenon of the first study is an organized but isolated thunderstorm system which produced many tornadoes and much damaging hail, again cap- tured in an ehanced observational network, this time deployed du- ring the 1985 O-K PRESTORM field project. That of the second study is a form of sloping roll circulation that often develops as part of the process of frontal formation. It is associated with alternating lines of heavy and little rain, and with alter- nating layers of saturated and extremely dry air aloft. Sanders has been a leader in synoptic meteorology for decades. He has established a record of using methods and theory in the forefront of atmospheric science in the study of those weather systems which directly affect human safety and property.