The accuracy of these 5-day mean temperature and precipitation forecasts has more than doubled since the 1970s. The accuracy of precipitation forecasts is less than that for temperature, even though the skill of both has increased at about the same rate. As a result of research over the last decade, monthly and seasonal forecasts of mean temperature and precipitation are now useful for specialized applications in major economic sectors, such as agricultural and energy interests, if utilized over a long period. There is reason for optimism that the utility of these long-range forecasts can be improved as computer models and statistical methods become more sophisticated. Claims to the contrary should be viewed with skepticism.
Opportunities exist for increasing the skill and utility of forecasts at all time ranges.
These new datasets and improved methods of incorporating the data into computer models should improve forecasts by providing models with a more realistic starting point for their forecasts. One of the main causes of forecast deterioration is the uncertainty in the initial state of the atmosphere. Techniques have been developed to assess the impact of initial conditions on the subsequent forecast. Such techniques provide forecasters with increasingly reliable information on the probability of disruptive weather phenomena occurring. Equally important is the continued evolution of numerical models based on increased model resolution and more realistic handling of the physics of the atmosphere.