Assessing the impact of advanced nowcasting systems on severe weather warning dissemination

On 3 November 2000 a severe storm developed southwest of Sydney, Australia and tracked Northeast. It hit the western suburbs of the city damaging buildings with large hail and tornadoes. At the time of the storm a number of advanced nowcasting systems were installed in the New South Wales regional office of the Bureau of Meteorology as part of the World Weather Research Programme (WWRP) Sydney 2000 Forecast Demonstration Project (FDP). This paper describes how the products of the nowcast systems were presented to the operational severe weather forecasters and provides an assessment of the impact of the systems on the forecast and severe weather warning process. It is demonstrated that different nowcasting systems, based upon different approaches to the problem of nowcasting, had applicability at different stages of the storm development and tracking. All systems were seen to offer some benefit to forecasters in complementary ways. There is evidence that forecaster confidence was increased resulting in earlier dissemination of forecasts.