The accuracy of weather forecasts for Melbourne, Australia

Abstract

An analysis of the accuracy, and trends in the accuracy, of medium-range weather forecasts for Melbourne, Australia, is presented. The analysis shows that skill is evident in forecasts of temperature, rainfall, and qualitative descriptions of expected weather up to 7 days in advance. The analysis also demonstrates the existence of a long-term trend in the accuracy of the forecasts. For example, Day-3 forecasts of minimum temperature in recent years (average error ∼1.6°C) are as skilful as Day-1 forecasts of minimum temperature in the 1960s and 1970s, whilst Day-4 forecasts of maximum temperature in recent years (average error ∼2.0°C) are more skilful than Day-1 forecasts of maximum temperature in the 1960s and 1970s. It is suggested that this trend may be largely attributed to: a combination of (1) enhancements in the description of the atmosphere's initial state provided by remote sensing and other observational technologies; (2) advances in broad-scale numerical weather prediction (NWP); and (3) improvements in the forecast process that are supported by good organizational management, including developing and implementing new prediction techniques, and careful succession planning. Copyright © 2008 Royal Meteorological Society.