Squall Lines and Extreme Rainfall in the Victoria, Australia Region

Linear precipitation systems are a consistent and noticeable year-round feature of Melbourne, and the surrounding region of Victoria, Australia. These systems are often convective in nature, frequently associated with cold fronts, and in some cases can lead to significant rainfall and flash flooding, especially in the Melbourne metro area. Squall lines have been the subject of a large amount of research in the US and other regions, but thus far relatively little has been done to understand the linear systems in this region. In order to understand the potential changes to rainfall in the Victoria region with a changing climate, it is useful to quantify squall line contribution to both total and extreme rainfall, to differentiate between those systems that lead to heavy rainfall and those that do not, and to explore the dynamical processes that contribute to the production of extreme rainfall by squall lines. To this end, we have mined the recently developed Australian Open Radar Database, identifying objects that meet a specific set of criteria appropriate for linear systems. This has been used to generate a set of cases that are being used to explore a number of questions including 1) What is the contribution of linear systems to total and extreme precipitation in Victoria? 2) What factors (e.g. orientation, rainrate, etc.) lead to systems that produce the most rainfall? 3) What are the dynamical processes that contribute to extreme rainfall in linear systems?