A new numerical weather prediction model has been developed for short-term forecasting (up to 36 hours) over the Australian region. It is a primitive equations, hydrostatic model which has variable resolution in the horizontal and vertical and which can be used in a 'telescoping' manner to provide fine mesh forecasts over a specified sub-domain. The main features of the model are a vertical mode initialisation scheme, semi-implicit time differencing, and the incorporation of physical processes including surface fluxes of momentum, heat and moisture, large-scale and convective precipitation, and a surface temperature diurnal cycle. In an attempt to achieve simplicity and flexibility the model has been designed to hold all variables in the memory of the computer, thereby greatly reducing both the amount of coding, and the time required for a forecast. The model has been run on a wide variety of case studies, designed to test the various aspects of the model. Three examples are given here as they well illustrate the forecasting capabilities of the model. The first case study is that of a Western Australian coastal trough, for which the inclusion of the surface temperature scheme is essential to capture the diurnal variation and movement of the trough. A second case study is the movement of a cold front for which resolution and rainfall parameterisations are crucial. Finally, an example of Tasman Sea cyclogenesis shows that the role of resolution is decisive, and that the surface temperature prediction scheme is necessary to predict the marked nocturnal cooling in the cold air surge west of the system.
Leslie et al. (Fri,) studied this question.